THE- OPTICAL 

ROTATING    POWER 


OF 


Organic  Substances,  and  Its 
Practical  Applications 

BY  ''  '  J'^ 

DI 


DOCTOR  HANS^AjroOL'f     5       # 

PROFESSOR  OF  CHEMISTRY  IN  THE  UNIVERSITY  OF  BERLIN 


ASSISTED  BY 


DR.  0.  SCHONROCK,    DR.  P.  LINDNER,  DR.  F.  SCHUTT, 
DR.  L.  BERNDT,  and  DR.  T.  POSNER 


UNlVERSn          SKCOXD    EDITION 

OF 


.CALII- 


AUTHORIZED  ENGLISH  TRANSLATION  WITH  ADDITIONS 

BY 
DR.  JOHN  H.  LONG, 

PROFESSOR  OF  CHEMISTRY  IN  NORTHWESTERN  UNIV.,  CHICAGO 

ILLUSTRATED 


EASTON,  PA.: 

THE  CHEMICAL  PUBLISHING  CO. 
i  got 


COPYRIGHT,  1902,  BY  EDWARD  HART. 


PREFACE  TO  THE  FIRST  EDITION 


Although  the  subject  of  the  optical  rotating  power  of  organic 
substances,  in  theoretical  as  well  as  in  practical  relations,  has 
been  growing  in  importance  for  a. long  time,  chemical  litera- 
ture possesses  thus  far  no  work  w^bkrir 'O'^erts  a  complete  dis- 
cussion of  the  whole  field,  and  studies  in  this  lire  may  be  car- 
ried out  only  by  the  aid  of  articles  "Scattered  t*i:MdgK  t'i<5  jour- 
nals. I  have  attempted  in  the  present  book  to  supply  the 
want  in  this  direction,  and  the  incentive  to  the  work  was  fur- 
nished by  an  article  which  I  published  some  time  since  in  Lie- 
big's  Annalen  der  Chemie,  Vol.  189.  This  article  dealt  with 
the  determination  of  the  specific  rotation  of  solid  substances, 
and  was  introduced  by  a  short  general  discussion  of  optical 
activity.  From  several  quarters  I  was  urged  to  enlarge  the 
article,  and,  especially  by  the  addition  of  a  description  of  all 
the  new  polarization  instruments  and  the  practical  uses  which 
may  be  made  of  them,  to  work  up  a  monograph  as  complete 
as  possible  of  the  subject  of  optical  rotation.  Such  an  under- 
taking appears  all  the  more  inviting  since  in  the  last  few  years 
different  observers  have  carried  out  investigations  in  this  field 
which  have  increased  our  knowledge  considerably,  and  which 
make  it  possible  to  give  a  certain  degree  of  completeness  to  the 
treatment  of  the  subject. 

From  a  theoretical  standpoint  the  optical  activity  of  organic 
substances  possesses  this  great  interest,  that  it  is  a  consequence 
of  a  peculiar  arrangement  of  the  atoms  within  the  chemical 
molecule,  and  therefore  stands  in  close  relation  to  the  question 
of  constitution.  However,  we  are  just  at  the  beginning  of 
investigations  of  the  relations  between  rotating  power  and 
chemical  structure,  and  for  future  study  there  is  material  at 
hand  abundant  and  full  of  promise.  To  lessen  the  labor  in 
work  of  this  kind,  especially  in  such  cases  where  results  may 
be  obtained  only  by  aid  of  exact  measurements,  it  became  nee- 


102026 


iv  PREFACE 

essary  to  go  fully  into  the  discussion  of  the  methods  for  the 
determination  of  specific  rotation.  Therefore,  the  use  of  the 
different  kinds  of  polarization  instruments  called  for  detailed 
treatment,  and  besides  this  the  determination  of  other  experi- 
mental data,  the  specific  gravity,  for  example,  should  be  ex- 
plained. In  this  work  I  have  taken  pains  to  give  methods  of 
the  greatest  possible  exactness  and  to  indicate  always  the  limits 
of  accuracy  which  may  be  reached  in  the  numerical  results.  If 
for  any  special  purpose  less  rigid  care  is  permissible  in  work 
the  observer  will  see  for  himself  how  the  procedure  may  be 
simplified^  -  •  ^UJ  :|  t 

In  a  pfactical   directionvas  is  well  known,  optical  rotation 


has  loa^  .Til  mikoportent  application  in  the  determi- 

nation of  sugar  ;  'arid  recently  the  optical  analysis  of  other  sub- 
stances, especially  that  of  the  cinchona  alkaloids,  has  been  also 
developed.  The  methods  applied  in  such  cases  are  fully  dis- 
cussed in  the  book  ;  for  the  sugar  chemist  the  description  of 
the  various  saccharimeters  and  the  corrections  which  must  be 
applied  in  using  them  may  be  of  interest,  and  in  part  new. 

The  optical  introduction,  which  possibly  may  be  of  interest 
to  many  chemists,  has  been  kept  as  concise  and  elementary  as 
possible.  I  have  also  touched  but  briefly  on  the  relations  be- 
tween crystalline  form  and  rotating  power,  as  this  topic  ap- 
pears to  belong  in  the  field  of  physical  crystallography. 

Finally,  the  table  of  contents  gives  full  information  concern- 
ing the  subjects  treated.  HANS  LANDOLT. 

A  \t  HKX,  January,  1879. 


PREFACE  TO  THE  SECOND  EDITION 


The  first  edition  of  this  work,  which  appeared  in  1879,  pre- 
sented a  general  view  of  our  knowledge  of  optical  rotation  as 
it  existed  at  that  time.  Now,  after  the  lapse  of  eighteen  years, 
when  a  new  edition  corresponding  to  our  present  position  is 
called  for,  we  have  to  deal  with  a  task  of  entirely  different  di- 
mensions. The  progress  which  has  been  made  in  the  last  two 
decades  in  the  field  of  optical  activity  rests,  so  far  as  the  theo- 
retical side  is  concerned,  mainly  upon  the  great  interest  aroused 
among  chemists  by  the  hypothesis  of  van't  Hoff  and  LeBel  on 
the  relation  between  rotating  power  and  the  atomic  structure 
of  carbon  compounds.  Since  1879,  when  this  doctrine  was 
still  in  its  infancy,  numerous  investigations  suggested  by  it 
have  been  carried  out,  the  results  of  which  have  abundantly 
confirmed  the  theoretical  requirements  in  all  cases,  so  that  to- 
day the  theory  may  be  presented  in  complete  and  fully  devel- 
oped form.  A  marked  widening  of  our  knowledge  may  be 
observed  in  other  directions  also  ;  for  example,  with  reference 
to  multirotation,  the  causes  of  variation  in  specific  rotation, 
rotation  dispersion,  etc.  In  a  practical  direction  progress  has 
been  made  in  the  improvement  of  polarization  apparatus  and 
in  the  development  of  methods  of  optical  analysis.  In  addi- 
tion, the  number  of  optically  active  substances  known  has  in- 
creased since  1879  from  300  to  over  700. 

From  the  whole  range  of  material  now  available  I  have 
worked  up  certain  parts  only  myself,  which  are  in  brief,  the 
subjects  discussed  in  the  following  theoretical  portions  of  the 
book  : 

Part  I.  General  Conditions  of  Optical  Activity. 
Part  II.   Physical  Laws  of  Circular  Polarization. 
Part  III.   Numerical  Values  for  the  Rotating  Power.    Spe- 
cific Rotation. 

In  a  section  of  Part  I  dealing  with  the  decomposition  of  ra- 


VI  PREFACE 

cemic  bodies  by  fungi  I  have  received  valuable  assistance  from 
Herrn  Prof.  Dr.  P.  Lindner,  Department  Director  of  the  In- 
stitute for  Fermentation  Industries  in  Berlin  ;  he  has  had  the 
kindness  to  prepare  a  chapter  on  the  subject  of  the  fungi  and 
the  forms  suitable  for  resolution,  the  methods  of  pure  culture 
and  experiments  in  resolution.  I  am  no  less  indebted  to  Dr. 
W.  Marckwald  and  Prof.  Dr.  H.  Traube,  who  have  rendered 
me  assistance  in  many  questions  of  stereochemistry  and  crys- 
tallography. 

In  order  to  secure  a  more  rapid  completion  of  the  following 
parts  of  the  book  I  was  obliged  to  seek  the  cooperation  of 
others,  and  to  the  extent  as  now  to  be  explained  : 

Part  IV.  ' '  Apparatus  and  Methods  for  the  Determination 
of  Specific  Rotation,"  by  Dr.  O.  Schonrock,  Assistant  in  the 
Physikalisch-Technischen  Reichsanstalt.  This  section  pre- 
sents, first,  a  description  of  the  different  polariscopes  and 
saccharimeters,  which  in  the  last  few  years,  and  especially 
through  the  work  of  Lippich,  have  reached  such  a  degree  of 
perfection  that  they  may  now  be  classed  among  the  most  ex- 
act of  instruments  for  physical  measurements.  In  order  to 
understand  these  instruments  and  the  methods  of  using  them, 
it  was  necessary  to  discuss,  not  only  their  construction,  but 
also,  especially,  the  optical  theory  on  which  their  use  is  based, 
and  it  was  further  necessary  to  go  into  an  accurate  definition 
of  the  kinds  of  light  employed  in  determining  angles  of  rota- 
tion, particularly  the  sodium  light.  The  author  has  discussed 
this  subject  in  detail  which  had  never  before  been  handled  as 
a  connected  whole.  This  was  all  the  more  desirable  since  there 
can  be  no  doubt  that  the  marked  discrepancies  found  in  the 
determination  of  the  specific  rotation  of  the  same  substance  by 
different  observers  do  not  always  depend  on  impurities  in  the 
material  used,  but  very  largely  on  improper  manipulation  of 
the  polariscope,  or  on  variations  in  the  character  of  the  sodium 
light  employed.  It  may  be  further  remarked  here  that  a  con- 
sideration of  these  sources  of  error  carries  with  it  no  increased 
difficulty  in  the  methods  of  observation,  as  one  might,  at  first 
thought,  assume. 

The  section  embraces  in  addition  a  discussion  of  all  known 
methods  for  determination  of  rotation  dispersion,  a  subject 


PREFACE  Vll 

which  up  to  the  present  time,  has  not  been  covered  in  its  re- 
lated bearings.  Finally,  the  chapters  on  sodium  lamps  and 
polarization  tubes  follow,  and  something  on  the  preparation  of 
solutions  and  the  determination  of  specific  gravity,  which,  as 
compared  with  the  corresponding  parts  of  the  earlier  edition, 
are  greatly  enlarged. 

In  the  preparation  of  this  whole  section  the  author  was  in 
position  to  make  use  of  the  experience  gained  in  many  investi- 
gations of  the  Physikalisch-Technischen  Reichsanstalt. 

Part  V.  "The  Practical  Applications  of  Optical  Rotation" 
was  written  by  Dr.  F.  Schiitt,  Royal  Councilor  and  Permanent 
member  of  the  Patent  Office.  As  regards  saccharimetry,  which 
makes  up  the  larger  part  of  the  section,  it  may  be  remarked 
that  it  was  considered  the  most  satisfactory  to  follow  the 
methods  officially  adopted  in  the  German  Sugar  Tax  Law  of 
May  27,  1896,  and  to  present  these  literally.  Among  other 
methods  of  polarimetric  analysis  those  concerned  with  the  de- 
termination of  cinchona  alkaloids  are  shortened  as  compared 
with  what  was  given  in  the  first  edition,  while,  on  the  other 
hand,  some  new  methods  have  been  added. 

Part  VI.  "The  Constants  of  Rotation  of  Active  Bodies  " 
has  been  compiled  mainly  by  Dr.  L.  Berndt  and  Dr.  Th.  Pos- 
ner,  formerly  assistants  in  the  II  Chemical  Laboratory  of  the 
Berlin  University.  The  section  on  ethereal  oils  was  prepared 
by  Dr.  Rimbach,  and  Prof.  Dr.  Thierfelder  had  the  kindness 
to  assist  in  securing  the  data  on  bile  acids  and  proteids.  A 
few  chapters  remained  in  my  hands. 

In  the  preparation  of  this  collection  of  experimental  data  it 
was  not  found  possible  to  include  all  the  statements  given  in 
the  literature,  as  this  would  have  unduly  increased  the  size 
of  this  part  of  the  work.  It  was  sufficient  in  many  cases  to 
quote  observations  in  part  and  refer  in  a  note  to  the  original 
articles.  For  the  same  reason  any  data  on  the  methods  of  prep- 
aration of  the  substances  observed  had  to  be  omitted,  although 
such  information  might  often  have  been  found  valuable.  The 
search  through  the  literature,  in  which,  however,  the  possi- 
bility of  overlooking  certain  data  could  not  be  wholly  excluded, 
was  complete  to  about  the  middle  of  1896.  From  that  date  it 
was  only  partial.  In  arranging  the  substances  in  order  the 


Vlll  PREFACE 

most  consistent  system  may  not  always  have  been  followed, 
but  by  aid  of  the  alphabetical  index  it  will  be  possible  to  find 
any  body  described. 

It  is  hoped  that  the  work  in  this  new  edition  also  will  fill  its 
place  as  a  text-  and  handbook  in  presenting  a  complete  resume 
of  our  knowledge  on  the  subject  of  optical  rotation. 

H.  LANDOLT. 

BERLIN,  December,  1897. 


TRANSLATOR'S    PREFACE 


The  two  editions  of  this  work  which  appeared  in  Germany 
in  1879  and  1898  enjoyed  there  a  great  and  well-deserved  pop- 
ularity. A  translation  of  the  first  edition  was  brought  out  in 
England  in  1882,  under  the  title :  "  Handbook  of  the  Polaris- 
cope  and  Its  Practical  Applications,"  and  contributed  not  a 
little  to  the  advance  of  methods  of  optical  analysis  in  that 
country  and  the  United  States.  Both  the  original  edition  and 
this  translation  have  been,  however,  long  out  of  print. 

The  scope  of  the  second  edition,  a  translation  of  which  I  have 
the  honor  of  presenting  to  American  and  English  readers,  is 
much  wider  than  that  of  the  first ;  the  main  points  of  differ- 
ence are  made  plain  in  the  author's  preface,  but  attention  may 
be  called  to  the  fact  that  the  detailed  discussions  in  Sections 
IV  and  V  of  Part  I  on  the  relations  between  the  rotating  power 
and  the  chemical  constitution  of  carbon  compounds,  along  with 
the  full  numerical  data  on  constants  of  rotation,  etc.,  render 
the  work  of  the  highest  value  to  investigators  in  many  fields 
of  pure  organic  chemistry.  Some  of  the  most  important  ad- 
vances in  this  direction  are  those  which  have  been  made  in  the 
methods  for  the  resolution  of  racemic  compounds.  This  sub- 
ject is  thoroughly  treated  by  the  author,  and  permission  was 
also  given  to  include  still  more  recent  work  in  the  English 
edition.  The  sections  which  I  have  added  in  this  connection 
relate  to  the  resolution  of  asymmetric  nitrogen  and  sulphur 
compounds  and  to  several  new  general  processes  of  resolution. 

I  have  made  also  many  additions  to  the  numerical  values  in 
Part  VI,  on  Constants  of  Rotation.  The  data  for  a  few  of 
these  were  sent  me  by  the  author,  while  the  others  were  taken 
from  the  journals  of  the  three  years  following  the  publication 
of  the  German  text. 

By  an  arrangement  between  the  publishers,  the  cuts  for  the 
illustrations  of  the  original  work  become  the  property  of  the 


X  PREFACE 

American  publisher  and  are  used  in  the  translation.  This  will 
account  for  the  appearance  of  some  German  words  in  connec- 
tion with  a  few  of  the  illustrations. 

In  conclusion  I  wish  to  acknowledge  my  indebtedness  to  my 
colleagues,  Professors  Crew  and  Dains,  of  Northwestern  Uni- 
versity, and  to  Dr.  H.  W.  Wiley,  of  Washington,  for  several 
suggestions  of  value,  and  to  my  assistant,  Mr.  Frank  Wright, 
for  help  in  the  reading  of  proof. 

J.  H.  LONG. 

CHICAGO,  January,  1902. 


TABLE  OF  CONTENTS 


GENERAL  CONDITIONS  OF  OPTICAL  ACTIVITY 
I.     Introduction,  Definitions  and  Formulas  of  Calculation 

1 .  Active  Bodies i     ^ 

2.  Measure  of  Rotating  Power,  Specific  Rotation 2 

3.  Molecular  Rotation 6 

4.  Historical 6 

II.     Classification  of  Active  Substances 

5.  Preliminary  Remarks.     Relation  of  Crystalline  Form  to  Rota- 

tion      7 

6.  First  Class.     Bodies  which  Possess  the  Power  of  Rotating  the 

Plane  of  Polarized  Light  in  the  Crystal  Condition  only 9 

List  of  Bodies  in  this  Class 9  and  13 

Behavior  of  Crystalline  Mixtures 1 1 

Behavior  of  Active  Crystals  in  Powdered  Condition 1 1 

7.  Second  Class.     Bodies  which  Rotate  in  both  Crystalline  and 

Amorphous  Form 14 

8.  Third  Class.     Bodies  which  are  Active  in  Amorphous  Condi- 

dition  only  (natural  liquids  or  solutions) 18 

List  of  Active  Carbon  Compounds 

1 .  Hydrocarbons 19 

2.  Monohydric  Alcohols  and  Derivatives 19 

3.  Dihydric  Alcohols  and  Derivatives 20 

4.  Trihydric  and  Tetrahydric  Alcohols 20 

5.  Pentahydric  Alcohols 20 

6.  Hexahydric  Alcohols 20 

7.  Heptahydric  Alcohols 21 

8.  Octahydric  Alcohols 21 

9.  Nonahydric  Alcohols 21 

10.  Acids  with  2  Atoms  of  Oxygen  and  Derivatives 21 

11.  "          3       "                  "                        "             21 

12.  4       "                                                          22 

13-  "          5      "                 •"                        "             23 

14-  6       "                                                         24 

15-  7       "                                           "             24 

16.  8       "                                                          25 

17.  Acids  with  More  than  8  Atoms  of  Oxygen  and  Deriva- 

tives    26 


Xll  TABLE  OF  CONTENTS 

1 8.  Oxyaldehydes,  Aldoses,  Aldehyde  Sugars 26 

19.  Oxyketones,  Ketoses,  Ketone  Sugars 28 

20.  Disaccharides 28 

21.  Trisaccharides 28 

22.  Polysaccharides 28 

23.  Carbohydrates 28 

24.  Gums 28 

25.  Pectin  Bodies 28 

26.  Alcohols  and  Acids  of  Unknown  Structure 28 

27.  Terpenes 29 

28.  Camphors  and  Derivatives 30 

29.  Ethereal  Oils,  Essential  Oils 33 

30.  Resin  Acids 34 

.;  i .  Aromatic  Amines 34 

32.  Alkaloids 34 

33.  Glucosides 36 

34.  Bitter  Principles,  Coloring-Matters 37 

35.  Bile  Acids 37 

36.  Protein  Substances 38 

37.  Derivatives  of  Asymmetric  Nitrogen 38 

38.  Derivatives  of  Asymmetric  Sulphur 38 

Enumeration  of  Active  Bodies 38 

III.     Nature  of  the  Rotating  Power 

$       9.  Distinction  between  Crystal  Rotation  and  Liquid  Rotation. 

Rotation  of  Vapors.     Molecular  Rotation 39 

£     10.  Optical  Theory  of  Circular  Polarization  in  Quartz 41 

£     ii.   Optical  Constitution  of  Active  Liquid  Substances 43 

'',.     12.    Investigations  of  Pasteur.     Molecular  Asymmetry 44 

v 
IV.     Relations  between  Rotating  Power  and  Chemical 

Constitution  of  Carbon  Compounds 

£     13.  van't  Hoff-LeBel  Theory 47 

$     14.  Asymmetric  Nitrogen   and  Sulphur 52 

V.    Optical  Modifications 

£     15.  General  Remarks 54 

A.  Calculation  of  Number  of  Optical  Modifications  of  a  Compound 

from  the  Number  of  Asymmetric  Carbons  Atoms  in  It 

I     16.  Numerical  Results 55 

B.  Physical  and  Chemical   Behavior  of  the  Optical  Modifications 

a .     Behavior  of  the  Antipodes 

'/      17-    Physical  Properties 67 

\     18.  Different  -r  of  the  Antipodes  on   Combination    with 

Active  Substances 68 

'i     19.   Physiological  Differences  between  the  Antipodes 71 


TABLE  OF  CONTENTS  Kill 

b.     Properties  of  Racemic  Compounds  and  Distinctions  between 
Them  and  Active  Modifications 

i.  Crystallized  Racemic  Compounds 

20.  Molecular  Weight 77 

21.  Crystalline  Form  and  Water  of  Crystallization 78 

22.  Density 79 

23.  Solubility 80 

24.  Melting-Point 83 

2.  Liquid  Racemic  Compounds 

25.  Are  These  to  be  Considered  as  Compounds  or  Mixtures 86 

26.  Results  of  Discussion 89 

C.  Formation  of  Racemic  Bodies 

27.  Production  of  Racemic  Bodies  by  Combination  of  the  Anti- 

podes.    Transition  Temperature 90 

28.  Production  of  Racemic  Bodies  from  One  of  the  Active  Forms 

by  Heat 93 

29.  Racemization  by  Conversion  of  Asymmetric  Bodies  into  Asym- 

metric Derivatives 96 

30.  Production  of  Racemic  Compounds  by  Conversion  of  Sym- 

metric Bodies  into  Asymmetric 97 

31.  Racemic  Compounds  from  Right-  and  Left-Rotating  Isomers 

of  Different  Configurations 98 

D.  Resolution  of  Racemic  Bodies 

32.  i.  Resolution  by  Crystallization,  Spontaneous  Resolution 99 

33.  2.   Resolution  by  Active  Compounds 102 

a.  Resolution  of  Racemic  Acids  by  Alkaloids 103 

b.  Resolution  of  Racemic  Bases  by  Tartaric  Acid no 

c.  Resolution  by  Stronger  Acids 113 

Resolution  by  Esterification  or  Saponification 115 

34.  3.   Resolution  by  Aid  of  Fungi,  and  Data  on  the  Fungi  Suita- 

ble for  Resolution 117 

List  of  Active  Forms  Obtained  by  Aid  of  Fungi 127 

E.     Formation  of  Active  Isomers 

35.  i.  From  Inactive  Materials.     Artificial  Preparation  of  Active 

Compounds 130 

36.  2.  From  Active  Materials 132 

37-  3-  Formation    of  Active   Bodies  in   the  Animal  or  Vegetable 

Cell 13? 

F.     Transformation  of  the  Active  Isomers 

38.  Reciprocal  Transformation  of  the  Antipodes 138 

39.  Reciprocal  Transformation   of    Active  Isomers    of   Different 

Configurations 14° 


xiv  TABLE  OF  CONTENTS 

G.     Inseparable  Modifications  of  Inactive  Configuration 

\     40.  Different  Classes  of  These  Bodies 140 

fc     41.  Differences  in  the   Properties  of   Racemically  Inactive  and 

Structurally  Inactive  Isomers 144 


SECOND 

PHYSICAL  LAWS  OF  CIRCULAR  POLARIZATION 

§     42.  Relation  of  Rotation  to  Length  of  Column 146 

§     43.  Dependence  of  the  Angle  of  Rotation  on  the  Wave-Length  of 

the  Ray.     Rotation  Dispersion 146 

\     44.  Rotation  Dispersion   of  Crystals 148 

\     45.  Rotation  Dispersion  of  Liquids  and  Dissolved  Substances 154 

\     46.  Anomalous  Rotation  Dispersion 157 


F»/\RT  THIRD 

NUMERICAL  VALUES  FOR  THE  ROTATING  POWER. 
SPECIFIC  ROTATION 

\     47.  Biot's  Conception  of  Specific  Rotation 165 

I.  Constant  Specific  Rotation  of  Dissolved  Substances 

\     48.  Original  Biot  Law 166 

II.  Variable  Specific  Rotation  of  Dissolved  Substances 
A.     Dependence  of  the  Specific  Rotation  on  the  Concentration 

49.  Recognition  of  Variation  in  Specific  Rotation 169 

>.  Determination  of  True  Specific  Rotation 170 

\     51.  Reduction  Formulas 175 

$     52.  Experimental  Proof  of  Biot's  Formulas 176 

I     53.  True  Specific  Rotation  of  Solid  Active  Substances 190 

'i     54.  Slight  Changes  in  Specific  Rotation  by  Variations  in  Concen- 
tration      194 

't     55.  Specific  Rotation  in  very  Dilute  Solutions 196 

I     56.  Minimum  Value  of  Specific  Rotation 197 

8     57.  Reversal  in  the  Direction  of  Rotation  by  Change  in  Concen- 
tration         2OI 

g     58.  Increase  or  Decrease  in  Specific  Rotation  with  Increasing  Di- 
lution of  Solutions 203 

B.     Dependence  of  the  Specific  Rotation  on  the  Nature  of  the  Solvent 

'',.     59.  Specific  Rotations  in  Different  Solvents 206 

C.     Dependence  of  the  Specific  Rotation  on  the  Temperature 
§     60.  Effect  of   Increase  of  Temperature  on  Liquid  and  Dissolved 

Active  Substances 207 


TABLE  OF  CONTENTS  XV 

D.    Causes  of  the  Changes  in  Specific  Rotation 

61.  a.  Electrolytic  Dissociation  in  Aqueous  Solutions 215 

62.  b.  Formation  or  Decomposition  of  Molecular  Aggregations  of 

Simple  Structure 227 

63.  c.  Presence  of  Complex  Polymerized  Molecules  (Crystal  Mole- 

x  cules)  in  the  Solution 232 

64.  d.  Combinations  of  the  Active  Body  with  the  Solvent.  Hydrates  234 

65.  <?.  Hydrolysis 236 

66.  f.  Small  Variations  in  the  Atomic  Equilibrium  of  the  Active 

Molecule 236 

E.  Specific  Rotation  of  Complex  Systems 

67.  Solutions  of  an  Active  Body   in  Two  Inactive  Liquids 237 

68.  Mixtures  of  Two  Active  Liquid  Substances 240 

69.  Solutions  of  Two  Active  Bodies  in  an  Inactive  Liquid 240 

70.  Addition  of  Inactive  Bodies  to  Solutions  of  Active  Substances  243 

A.   Tartaric  Acid  and  Malic  Acid 

a.  Influence  of  Alkali  Salts  on  the  Rotation  of  Tartrates 243 

b.  Influence  of  Boric  Acid  on  the  Rotation  of  Tartaric  Acid 246 

c.  Action  of  Molybdates  and  Tungstates  on  Tartaric  Acid 248 

d.  Action  of  Molybdates  and  Tungstates  on  Ordinary  Malic  Acid  250 

B.  Sugars 

a.  Changes  in  the  Rotation  of  Cane  Sugar  by  Alkalies  and  Salts  251 

b.  Dextrose  and  Calcium  Chloride 253 

c.  Action  of  Borax  on  Bodies  of  the  Mannitol  Group 253 

d.  Action  of  Acid  Sodium  and  Ammonium  Molybdate  on  Man- 

nitol, Sorbitol,  or-Mannoheptitol  and  Rhamnose 256 

F.  Multirotation 
i.  Multirotation  of  the  Sugars 

71.  Preliminary  Remarks 257 

72.  Sugars  Showing  Multirotation 259 

73.  Rate  of  Change  in  Rotation 266 

74.  Cause  of  Multirotation  of  the  Sugars 273 

//.  Multirotation  of  Oxyacids  and  Their  Lactones 

75-  General  Conditions  and  Observations 275 

///.  Multirotation  of  Other  Substances 

76.  Observations 281 

G.  Relations  Between  the  Amount  of  Rotation  and  Chemical 
Constitution 

77.  Preliminary  Remarks 282 

/.  Isomeric  Bodies 

78.  a.  Metamerism.     Structural  Isomerism 285 

79.  b.  Position  Isomerism  in  Benzene  Derivatives 286 


XVI  TABLE  OF  CONTENTS 

I     80.  c.  Stereoisomeric  Bodies 289 

//.  Homologous  Series 

\    81.  Changes  in  Molecular  Rotation  by  addition  of  CH2 290 

///.  Effect  of  Linkage  of  the  Carbon  Atoms 

\    82.  a.  Change  from  Single  to  Double  Bond  by  Loss  of  2  Atoms  of  H  293 
\     83.  b.  Change  from  Double  to  Triple  Bond  Between  Carbon  Atoms  294 
<<     84.  c.    Change  from  Chain  Compound  to  Cyclic  Carbon  Compound  294 
£     85.  d.  Compounds  with  Several  Asymmetric  Carbon  Atoms.    Sum- 
mation of  the  Rotating  Power  of  Active  Groups.     Optical 

Superposition 296 

IV.  Dependence  of  the  Rotating  Power  of  an  Active  Atomic 
Complex  on  the  Masses  of  the  Four  Radicals  Joined  to 

the  Asymmetric  Carbon  Atoms.  Hypothesis  ofGuye 
$     86.  Guye's  Hypothesis 299 


FOURTH 

APPARATUS  AND  METHODS  FOR  THE  DETERMI- 
NATION OF  THE  SPECIFIC  ROTATION 

$     87.  General  Conditions 306 

A.  Measurement  of  the  Angle  of  Rotation 

$     88.  Ordinary  and  Polarized  Light 306 

\     89.  Rotation  of  the  Plane  of  Polarization 308 

\     90.  Iceland  Spar  Prisms 308 

$     91 .  Polarizer  and  Analyzer 311 

\     92 .  Polarization  Apparatus 713 

$     93.  Determination  of  the  Direction  and  Angle  of  Rotation 314 

a.     Polarization  Instruments 

2     94.  Polarization  Apparatus  and  Saccharimeters 316 

\     95.  Construction  of  the  Polariscopes 316 

\     96.  Path  of  the  Rays  in  the  Polariscope 319 

$     97.  Making  the  Observation 325 

a.     Older  Forms  of  Apparatus 
i.  Biot  (Mitscherlich)  Polariscope 

$     98.  Description  of  the  Instrument 326 

'i     99.  Observation  with  Homogeneous  Light 327 

2.  Robiquet's  Polariscope 

2   loo.  Description  of  the  Instrument 328 

$  101 .  Theory  of  the  Soleil  Double  Plate 329 

I.  The  Observation 33o 

3.  Wild's  Polaristrobometer 

$  103.  Description  of  the  Instrument 331 

$  104.  The  Observation 333 


TABLE  OF  CONTENTS  XV11 

ft.     Half-Shadow  Instruments 

\   105.  Principle  of  the  Half-Shadow  Apparatus 335 

\  106.  Influence  of  the  Source  of  Light 338 

\   107.  Calculation  of  the  Sensitiveness 340 

},   108.  Methods  of  Observation 341 

'4.   109.  Jellett  s  Polariscope 342 

<<   no.  Cornu's  Polarizer 344 

4.  Laurent's  Half-Shadow  Instrument 

\   in.   Description  of  the  Apparatus 344 

3   112.  Principle  of  the  Laurent  Polarizer 345 

</   113.  Accuracy  of  the  Laurent  Apparatus 348 

5.  Lippich's  Half-Shadow  Polarimeter 

2   1 14.  Instrument  with  Double  Field 35 1 

2   115.  Instrument  with  Triple  Field 354 

'i   1 16.  Instrument  According  to  Lurnmer  with  Quadruple  Field 356 

6.  Mechanical  Constructions  of  the  Lippich  Polarization 
Apparatus 

\   117.  Landolt's  Apparatus 358 

\   1 1 8.  Apparatus  with  Adjustable  Length 360 

\  119.  Apparatus  for  Especially  Exact  Measurements 361 

\   1 20.  Allowance  for  the  Earth's  Magnetism 364 

7.  Lummer's  Half-Shadow  Apparatus 

\  121.  Description  and  Theory  of  the  Instrument 365 

b.     Saccharimeters 

\  122.  Simple  Wedge  Compensation 366 

\   1 23.  Double  Wedge  Compensation 368 

\  124.  Preparation  of  Sugar  Scale  for  Polariscopes  with  Circular  Grad- 
uation    369 

\   125.  Preparation  of  Sugar  Scale  for  Saccharimeters 371 

\   126.  The  Ventzke  Sugar  Scale 372 

\  127.  The  loo  Point  of  the  Saccharimeter 374 

$   128.  Testing  the  Saccharimeter  Scale 376 

\  129.  Observation  of  Solutions  in  the  Saccharimeter ....  382 

</   130.  Effect  of  Temperature  on  the  Saccharimeter  Reading 383 

1.  Soleil- Ventzke  Saccharimeter 

>/,   131.  Description  of  the  Instrument 385 

2.  Half-Shadow  Saccharimeters 

\  132.  Construction  of  the  Instruments 387 

%  133.  Half-Shadow  Saccharimeters  with  Single  Wedge  Compensa- 
tion    388 

|  134.  Half-Shadow  Saccharimeters  with  Double  Wedge  Compensa- 
tion    388 

>/.   135.  Beet  Juice  Saccharimeter  with  Enlarged  Scale 389 


xvill  TABLE  OF  CONTENTS 

$  136.  Half-Shadow  Saccharimeter  of  Peters 391 

\   137.  Half-Shadow  Saccharimeter  of  Fric 392 

c.     Illuminating  Lamps 
i.  Lamps  for  White  Light 

\  138.  Schmidt  and  Haensch  Gas  Lamps 393 

£  139.  The  Hinks  Petroleum  Lamp 394 

|  140.  Lamps  with  VVelsbach  Light 394 

$  141.  Lamp  for  Electric  Light 394 

§  142.  The  Zirconium  Light 394 

2.  Lamps  for  Homogeneous  Light 

\  143.  Simple  Sodium  Light  Lamps 395 

\  144.  Pribram's  Sodium  Lamp 396 

\  145.  Landolt's  Sodium  Lamp 397 

§  146.  Intense  Sodium  Light 398 

3.  Purification  of  the  Sodium  Light.     Optical  Center  of  Gravity 

§  147.  Lippich  Sodium  Light  Filter 399 

§  148.  Optical  Center  of  Gravity  of  Sodium  Light 402 

\  149.  Spectral  Purification  of  Sodium  Light ' 405 

\  150.  Dependence  of  the  Optical  Center  on  the  Brightness 407 

\  151.  Absolute  Determination  of  the  Rotation  of  Sodium  Light  for 

Quartz 413 

2  152:  Relation  of  the  Angles  of  Rotation,  aD  and  a.j 415 

8  ;53-  Optical  Center  of  Gravity  of  White  Light 416 

d.  Determination  of  Rotation  Dispersion 

\  154.  Method  of  Broch 419 

^ .  Method  of  v.  Lang 423 

$   156.  Method  of  Lippich 425 

\  157.  Method  of  Lommel 427 

\  158.  Method  of  Landolt  with  Ray  Filters 429 

$   159.  The  Arons-Lummer  Mercury  Lamp 433 

B.  Construction  of  Polarization  Tubes  and  the  Meas- 

urement of  Their  Length 

\  160.  Construction  of  the  Tubes  and  Method  of  Closing  Them  by 

End-Plates  of  Glass ...   436 

fc   161.  Water-Jacket  Tubes  and  Water-Heating  Apparatus 438 

\  162.  Calculation  of  Specific  Rotation  with  Consideration  of  Tem- 
perature    441 

£   163.  Schmidt  and  Haensch  Control  Tube 441 

\  164.  Measurement  of  the  Tube  Length 443 

C.  Determination  of  Percentage  Strength  of  Solutions 

|  165.  Reduction  of  Weighings  to  Vacuo 444 

f  166.  Preparation  of  Solutions  by  Weighing 446 

.§  167.  Change  in  Percentage  Strength  on  Filtration  of  Solutions 448 


TABLE  OF  CONTENTS  xix 

D.  Determination  of  Specific  Gravity 

168.  Construction  and  Use  of  the   Pycnometer 449 

169.  Calculation  of  the  Specific   Gravity - 454 

170.  Variations  in  Specific  Gravity   with  Temperature 456 

E.  Determination  of  the  Concentration  of  Solutions 

171.  Calculation  of  the  Concentration   from  the  Specific  Gravity 

and  Percentage  Strength 458 

172.  Preparation  of  Solutions  in  Measuring  Flasks 459 

F.  Effect  of  the  Different  Errors  of  Observation  on  the 
Specific  Rotation 

173.  Calculation  of  Errors 461 


F»/\RT 

PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 
I.     Determination  of  Cane  Sugar.     Saccharimetry 

A.    Determination  of  Sugar  with  Instruments  Having  a  Circular 
Graduation 

\   174.  Calculation  of  Concentration.     Formulas 463 

|  175.  Concentration  and  Variable  Rotation 463 

B.    Determination  of  Cane  Sugar  with  Application  of  Wedge 
Compensation  Instruments 

\   1 76.  Preliminary  Remarks 466 

|  177.  Practical  Methods  of  Saccharimetry  According  to  the  Provi- 
sions of  the  German  Sugar  Tax  Law 467 

II.     Determination  of  Milk  Sugar 

<<   178.  Constants  for  Milk  Sugar 488 

|  1 79.  Determination  of  Sugar  in  Milk 489 

III.  Determination  of  Glucose 

§  180.  Calculation  of  Formulas 491 

\  181 .  Sugar  in  Diabetic  Urine 493 

IV.  Determination  of  Maltose 

§  182.  Calculation  of  Formulas 495 

V.  Determination  of  Galactose 

\  183.  Calculation  of  Formulas 496 

VI.  Determination  of  Camphor 

§  184.  Formulas  and  Method 497 


XX  TABLE  OF  CONTENTS 

VII.  Determination  of  Cinchona  Alkaloids 

§  185  Calculation  of  Formulas 498 

VIII.  Determination  of  Cocaine 

§  186.  Calculation  of  Formulas 5°! 

IX.  Determination  of  Nicotine 

§  187.  Formulas  and  Method 503 


SI^CTH 

CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Group 

1.  Hydrocarbons 

Ethylamyl,  Propylamyl,  etc 505 

2.  Alcohols  with  One  Atom  of  Oxygen 

Amyl  Alcohol  and  Derivatives 506 

Hexyl  Alcohol,  Methylhexyl   Carbinol 510 

3.  Alcohols  with  Two  to  Four  Atoms  of  Oxygen 510 

4.  Alcohols  with  Five  Atoms  of  Oxygen 

Pentitols  :  Arabitol,   etc 511 

5.  Alcohols  with  Six  Atoms  of  Oxygen 

Hexitols  :  Mannitol,  Sorbitol,  etc 511 

6.  Alcohols  with  Seven  Atoms  of  Oxygen 

Mannoheptitol,  etc 512 

7.  Acids  with  Two  Atoms  of  Oxygen 

Valeric  Acid,  Caproic  Acid 513 

8.  Acids  with  Three  Atoms  of  Oxygen  and  Derivatives 

Lactic  Acid  and  Salts 515 

Oxybutyric  Acid,  Leucin,  etc 518 

Mandelic  Acid  and  Derivatives 520 

9.  Acids  with  Four  Atoms  of  Oxygen  and  Derivatives 

Glyceric  Acid  and  Salts,  etc 523 

10.  Acids  with  Five  Atoms  of  Oxygen 

Malic  Acid,  Salts  and  Esters 526 

Oxysuccinic  Acids  and  Derivatives 536 

Shikimic  Acid  and  Derivatives 543 

n.  Acids  with  Six  Atoms  of  Oxygen 

Arabonic  Acid,  Ribonic  Acid,  etc 544 

Tartaric  Acids 546 

12.  Acids  with  Seven  Atoms  of  Oxygen 

Gluconic  Acid,  Gulonic  Acid,  etc 565 

13.  Acids  with  Eight  Atoms  of  Oxygen 

Glucoheptonic  Acid,  Saccharic  Acids 569 


TABLE  OF  CONTENTS  XXI 

14.  Acids  with  Nine  Atoms  of  Oxygen 

Glucooctonic  Acid,  etc 572 

15  Acids  with  Ten  Atoms  of  Oxygen 

Gluconononic  Acid,  etc. 573 

16.  Oxyaldehydes,  Aldoses,  Aldehyde  Sugars 

Arabinose,  Xylose,  Glucose,  etc 574 

17.  Oxyketones,  Ketoses 

Fructose 589 

18.  Invert-Sugar 591 

19.  Disaccharides,  Saccharoses 

Cane-Sugar 596 

Milk-Sugar,  Malt-  Sugar,  etc 599 

20.  Trisaccharides  and  Polysaccharides 

Raffinose,  Melitose,  etc 605 

21.  Carbohydrates 

Soluble  Starch,  Dextrines,   etc 607 

22.  Gums 

Arabin,  Wood-Gum 61 1 

23.  Camphors  and  Terpenes 

A.  Aliphatic   Terpenes 612 

B.  Terpan    Group 614 

C.  Camphan  Group 627 

D.  Polyterpenes 658 

24.  Ethereal  Oils 660 

25.  Resin  Acids 666 

26.  Alkaloids 

Of  Aconite  Species,  etc 667 

Cinchona  Alkaloids 671 

Of  Coca  Leaves 698 

Of  Opium 701 

Strychnos  Alkaloids 706 

Other  Alkaloids  and  Bases 707 

27.  Glucosides 

Salicin  Helicin,  Amygdalin,  etc 713 

28.  Bitter  Principles  and  Indifferent  Bodies 

Santonin  Group 715 

Other  Vegetable  Substances 717 

29.  Biliary  Substances 718 

30.  Gelatinous  Substances 723 

31.  Protein  Bodies 

Albumins,  Albumoses,  etc 724 

General  Index 729 

Index  of  Active  Substances 737 


PART  FIRST 


General  Conditions  of  Optical  Activity 


1.  INTRODUCTION,   DEFINITIONS,  AND    FORMULAS   OF    CAL- 

CULATION 

i.  Active  Bodies. — Those  substances  which  possess  the  property 
of  rotating  through  a  certain  angle  the  olane  of  polarization  of 
a  ray  of  polarized  light  which  passes  through  them  are  desig- 
nated as  optically  active,  or  circular ly^pnlari^ing, .  V-4Ie  the 
property  itself  is  described  as  optical  rotating  power. 

The  property  of  optical  activity  is  shown  by  :  i .  A  number 
of  inorganic  and  organic  substances  in  crystalline  condition. 

2.  By  a  large  number  of  carbon  compounds  when  exposed  to 
the  polarized  ray  in  liquid  or  dissolved  condition.     In  bodies  of 
the  first  class  the  cause  of  the  optical  activity  is  due  to  peculiarity 
of  crystalline  structure,  while  in  the  second  it  is  due  to  an 
unsymmetrical  arrangement  of  the  atoms  within  the  molecule. 

According  to  the  direction  in  which  the  rotation  of  the  plane 
of  polarization  takes  place  active  bodies  are  either  : 

Dextrorotatory,  with  the  sign  -f-  or  d, 
Laevorotatory         "  —  or  /. 

If  an  organic  ^-compound  be  subjected  to  chemical  trans- 
formation, the  derivatives  may  be  in  part  also  right  rotating, 
or  they  may  be  in  part  even  left  rotating.  In  order  to  indicate 
the  derivation  from  the  original  parent  substance,  the  letter,  d, 
is  retained  as  a  prefix  for  all  bodies  of  the  group,  without, 
however,  expressing  by  it  the  direction  of  rotation  in  the 
derivative.  If  this,  also,  is  to  be  shown,  it  can  be  done  by  the 
addition  of  the  +  or  —  sign.  The  expressions,  d  (-f-)  and  d 
( — ) ,  indicate  right  and  left  rotating  derivatives  of  a  dextro- 
parent  substance,  while  /  ( — )  and  /  (-f  )  indicate  the  direction 
of  rotation  of  the  derivatives  of  a  laevorotating  substance. 


2  GENERAL   CONDITIONS   OF   OPTICAL    ACTIVITY 

Many  bodies  occur  in  isomeric  forms  with  optically  different 
behaviors.  There  are  recognized  : 

/.  Active   modifications,    found   always   in  two   forms  con- , 
stituting   the   so-called   optical  antipodes,  inasmuch  as  under 
like  conditions,  one  form  rotates  as  strongly  to  the  right  as 
the  other  to  the  left.     These  are  designated  as  the  ^-form  and 
the  /-form. 

2.  Inactive  modifications  which  are  mixtures  or  compounds 
of  the  active  antipodes  in  equal  proportions,  and  which  may 
be  split  up  into  these  by  the  action  of  certain  agents.  For  these 
so-called  mow//';  bodies,  the  symbols;- or  <//,  or  (d  -f  /)  are  in  use. 

j.  Inactive  modifications  which  cannot  be  decomposed  into 
the  ai.-tive  forms.  These  will  be  indicated  by  tl  in  the  follow- 
in-  piges. 

2.  Measure  of  Rotating  Power,  Specific  Rotation. — In  active 
crystals  the  observed  angle  of  rotation  varies  with  the  thick- 
ness of  the  plate  used,  and  it  is  customary  to  reduce  this  rotation 
to  that  of  a  plate  i  millimeter  in  thickness  for  comparison. 

In  order  to  express  the  optical  activity  of  dissolved  solid  or 
of  liquid  carbon  compounds  the  conception  of  specific  rotation, 
introduced  by  Biot,  is  employed.  By  this  term  is  understood 
that  angle  of  rotation  which  a  liquid  would  produce  if  it  contained 
in  one  cubic  centimeter  one  gram  of  active  substance,  and  opposed 
a  column  one  decimeter  in  length  to  the  passage  of  the  polarized 
ray.  This  datum  calculated  from  observation  is  represented, 
following  Biot's  suggestion,  by  the  symbol  [«]. 

The  following  points  concerning  specific  rotation  may  be 
noticed  here  in  passing,  a  fuller  discussion  being  reserved  for 
a  later  chapter.  As  experiment  has  shown  the  angle  of  rota- 
tion produced  in  a  polarization  apparatus  by  an  active  liquid 
is  dependent  on  : 

/.  The  length  of  column  through  icJiich  the  light  passes,  and 
n  fact  exactly  proportional  to  this  length. 

1  The  letter  i  i»  often  used  to  indicate  racemic  compounds,  but  it  appears  better 
to  use  it  only  for  the  inactive  Ixxiie-,  which  .cannot  be  split  up.  In  order  to  avoid 
danger  of  confusion  with  iso-compound.s  which  are  sometimes  indicated  with  i,  it 
would  be  better  to  use  for  these  the  letter  /.  The  use  of  r  instead  of  d  for  right 
routing  substances  should  be  wholly  discarded,  inasmuch  as  it  does  not  conform 
to  international  use,  and  because,  further,  it  is  already  applied  to  racemic  h 


MEASURE   OF   ROTATING   POWER  3 

2.  The  wave  length  of  t/ie  light  ray  employed.  —  As  in  the 
case  of  refraction  of  ordinary  light  the  rotation  in  general 
increases  with  decreasing  wave  length  ;  it  is  therefore  least  for 
red  and  greatest  for  the  violet  rays.  Commonly  homogeneous 
yellow  light,  corresponding  to  the  Fraunhofer  line  D,  is  em- 
ployed in  the  observations.  By  measuring  the  rotation  for 
different  rays  the  rotation-dispersion  of  the  substance  is 
determined. 

j.  The  temperature  of  the  liquid.  —  With  certain  substances 
this  has  but  little  influence,  but  in  many  others  it  produces 
either  an  increase  or  a  decrease  in  the  angle  of  rotation.  As  a 
normal  temperature,  20°  C.  should  be  taken. 

The  following  observations  are  required  to   determine  the 

specific  rotation  of  substances  which  are  in  themselves  liquids  : 

a.  The  amount  of  rotation  to  the  right  or  left  for  a  definite 

color,   and  expressed  in  circular  degrees,  and  decimals 

of  the  same.      (The  use  of  minutes  and  seconds  is  not 

customary.  ) 

/.  The  length  of  the  observation  tube,  in  decimeters. 
t.  The  temperature  of  the  liquid  in  the  tube. 
d.  The  density  of  the  liquid    at  the   temperature,   t,   and 
referred  to  water  at  4°  C.  as  the  basis,  in  which  case  d 
expresses  the  weight  in  grams  of  one  cubic  centimeter. 
If  the  density  is  found  by    aid  of  a  pycnometer  which 
holds   at    the  temperature  of  20°    W  grams  of  water, 
and  F  grams  of  the  liquid,  then 


5^  —  0. 


X  0.99705    —  0.00120. 

According  to  the  above  definition,   the  specific  rotation  is 
expressed  by  the  formula  : 


If  the  kind  of  light  used  and  the  temperature  are  also  added 
the  specific  rotation  is  a  characteristic  constant  of  the  sub- 
stance in  question.  For  example,  for  nicotine  : 

[a]sp=       -  161.55°- 
Solid  active  substances  are  brought  into  solution  by  aid  of 


4  GENERAL   CONDITIONS   OF   OPTICAL   ACTIVITY 

inactive  solvents.     The  preparation  of  solutions  may  be  effected 
in  two  ways  : 

i.  By  the  aid  of  a  measuring  flask  the  contents  of  which, 
in  true  cubic  centimeters  at  a  definite  temperature  (as  2O°C.  ), 
is  known.  A  certain  weight  of  the  active  substance  is  weighed 
into  the  empty  flask,  the  solvent  is  added  to  effect  solution, 
and  then  filled  up  to  the  mark.  From  this  we  have  : 

c.  The  concentration,  that  is  the  number  of  grams  of  active 
substance  in  100  cubic  centimeters  of  solution,  and  the 
specific  rotation  follows,  under  the  assumption  that  the 
rotation  is  proportional  to  the  concentration,  by  : 

(ID  M 


2.  A  weighed  amount  of  the  active  substance  is  dissolved 
in  the  liquid  in  a  flask  which  may  be  stoppered,  and  the 
weight  of  the  solution  determined.  From  these  data  there 
may  be  calculated  : 

p    the  per  cent,  amount  of  active  substance. 
q    the  per  cent,  amount  of  inactive  solvent. 

Then,  in  order  to  find  the  concentration  of  the  solution,  its 
specific  gravity,  d,  at  a  definite  temperature,  as  20°,  must  be 
found.  As  pd—  c,  then  : 


This  last  method  is  to  be  applied  when  it  is  desired  to 
investigate  the  dependence  of  the  specific  rotation  of  a  body  on 
the  composition  of  its  solution. 

In  stating  the  specific  rotation  of  a  dissolved  substance  the 
solvent  must  always  be  given,   also  the  concentration  or  the 
percentage  strength  with  the  specific  gravity.     Observations 
may  be  expressed  in  the  following  form.     For  example  : 
(98  per  cent,  alcohol,  by  volume, 

Uurel  camphor  >  e  =  *"5)'  M"=  +  44'*>°- 

(glacial  acetic  acid,  p       39.72,  a4    - 

1.0113),  [«]£-:  +  47-I&0  • 

As  experience  lias  shown  there  are  certain  substances  for 
which  the  specific  rotation,  as  calculated  from  solutions  of 


GENERAL    FORMULAS    FOR    ROTATION  5 

different  concentrations,  remains  constant  or  at  most  suffers 
but  a  very  slight  change.  For  such  bodies,  for  example,  cane- 
sugar  or  milk-sugar  dissolved  in  water,  the  angle  of  rotation 
is  exactly  proportional  to  the  concentration,  and  therefore  by 
the  following  formula, 

I  OCX* 


the  strength  of  a  solution  of  the  substance  may  be  found  if 
the  value  of  [<*]  is  known.  Polarimetric  analysis,  especially 
of  sugars,  is  based  on  this  fact. 

With  the  great  majority  of  active  substances,  however,  it  has 
been  observed  that  the  specific  rotation  increases  or  decreases, 
with  increasing  dilution  of  the  solution,  and  at  very  different 
rates  for  different  substances  ;  sometimes  the  direction  of 
rotation,  even,  may  change.  In  such  cases,  there  must  be  an 
alteration  of  the  nature  of  the  substance  by  the  action  of  the 
solvent.  If  the  value  of  [<*],  for  a  number  of  solutions  of 
different  strengths  has  been  found,  it  wrill  be  possible  to 
express  the  dependence  of  the  specific  rotation  on  the  factors 
p  and  gby  the  following  formulas,  in  which  the  constants,  A, 
B,  and  C,  or  a,  b,  and  c  are  determined  by  experiment  : 

(V)  [a]  =A  +  Bq 

(VI)  [a]   ==  a  +  bp, 
or 

(V)  [a]  '=A  +  JB?+  Cf 

(VI')  [>]  ==  a  +  bp  +  #* 

In  the  formulas,  (V)  and  (V),  the  constant  A  expresses 
the  specific  rotation  of  the  active  substance  in  undiluted  con- 
dition, wrhile  B  and  C  show  the  change  produced  by  i  per  cent. 
of  the  inactive  solvent.  If  q  is  taken  equal  to  100,  the  specific 
rotation  in  infinite  dilution  is  given. 

In  the  formulas,  (VI)  and  (VF),  the  constant  a  corresponds 
to  the  specific  rotation  in  infinitely  great  dilution,  while  the 
value  for  the  pure  substance  is  given  when/>  is  taken  equal  to 

100. 

If  it  be  desired  to  replace  the  constants,  A  and  B,  by  a  and 
£in  the  formulas,  (V)  and  (VI),  and  vice  versa,  we  take 


6  GENERAL   CONDITIONS   OF   OPTICAL  ACTIVITY 

A  —  a  +  ioo  b  a  =  A  -f  100  # 

B=  —  b  b=  —  B 

In  the  3-term  formulas,  we  have  : 

^  =  a  -f  ioo  b  -f  10,000  ^    a  —  A  +  ioo  ^  -h  10,000  C 
/?  —    -  b  —  200  c.  b  =  —  B  —  200  C. 

C=c.  c  =  C. 

If,  further,  the  constants  of  the  equation, 
[a]  =a  +  ty+  &2, 

have  been  determined  for  an  active  substance,  with  molecular 
weight  J/,  and  if  it  be  desired  to  alter  them,  so  as  to  make 
them  apply  for  a  derivative  (hydroxide  or  salt,  for  example), 
with  the  molecular  weight  M1  ',  which  leads  to  the  formula, 


then,  we  place  : 

M 


3.  Molecular  Rotation.  —  This  term  is  applied  to  the  product  of 
the  molecular  weight  and  specific  rotation  of  a  body,  and  is 
represented  by  the  symbol  [M].  But,  to  avoid  the  use  of 
inconveniently  large  numbers,  it  is  customary  to  take  the 
one-hundredth  part  of  this  product  ;  thus  : 


ioo 

In  this  case,  [J/]  expresses  the  rotation  which  would  follow, 
if  each  cubic  centimeter  of  the  solution  contained  i  gram- 
molecule  of  the  active  substance,  and  the  length  of  the  liquid 
column  were  i  millimeter.  The  molecular  rotation  is  applied 
in  making  stoichiometric  comparisons. 

4.  Historical.  —  The  rotation  of  the  plane  of  polarization  was 
noticed  first  in  quart/  plates  by  Arago,  in  1811.  In  1815 
Biot  and  Seebeck  discovered  the  optical  activity  of  certain 
organic  substance^  '  oil  of  turpentine,  and  aqueous  solutions 
:^ar  and  tartaric  acid).  Through  a  long  series  of  investi- 
gations, extending  over  a  period  of  47  years  (  from  1  8  1  3  to  1  860)  , 


CLASSIFICATION    OF   ACTIVE   SUBSTANCES  7 

Biot  established  the  important  physical  laws  and  the  general 
nature  of  the  phenomena  observed.  In  1823,  Fresnel  published 
a  theory  of  the  effects  as  noticed  in  quartz  in  which  he  intro- 
duced the  term  circular  polarization.  In  1831,  Herschel  dis- 
covered the  important  relation  existing  between  the  rotating 
power  in  quartz  crystals,  and  the  development  of  their  faces. 
A  further  fundamental  discovery  in  this  field  wras  made  by 
Pasteur,  who  found  in  1848,  in  the  examination  of  tartaric 
and  racemic  acids,  that  one  and  the  same  active  substance  may 
occur  in  oppositely  rotating  and  in  inactive  modifications. 
The  last  great  advance  in  the  subject  was  brought  about  in 
1874  by  van  't  Hoff  and  LeBel,  who  independently  discovered 
the  relation  existing  between  the  rotating  power  of  organic 
substances  and  their  atomic  constitution,  in  the  discussion  of 
which  the  notion  of  asymmetric  carbon  atoms  was  introduced 
in  the  science. 


II.  CLASSIFICATION  OF  ACTIVE  SUBSTANCES 

5.  Preliminary  Remarks,  Relation  of  Crystalline  Form  to  Rotation. 
— All  bodies  which  in  crystalline  condition  or  in  solution  have 
the  power  of  rotating  the  plane  of  polarization  of  light 
crystallize,  as  was  shown  by  Pasteur,1  in  so  called  hemihedral 
forms,  and  the  crystals  of  the  right  and  left  modifications  of 
an  active  substance  are  enantiomorphous. 

A  hemihedral  crystalline  polyhedron  is  not  superposable  on 
its  mirror  image.  The  original  form  and  that  corresponding 
to  its  image  are  related  as  is  the  right  hand  to  the  left ;  they 
exhibit  the  peculiarity  described  in  crystallography  as  enantio- 
morphism. 

Hemihedral  forms,  from  a  geometric  standpoint,  can  possess 
axes  of  symmetry  only,  but  no  center  of  symmetry  and  no 
planes  of  simple  or  compound  symmetry.2 

In  the  thirty-two  possible  crystalline  groups,  eleven  are 
found  with  hemihedral  forms,  and  these  are  given  below  with 

1  Pasteur  :  Compt.  rend.,  26,  535 ;  27,  401 ;  35,  180.  Compare  also  Becke' :  Min. 
und  petrogr.  Mitth.  v.  Tschermak,  10,  414  (1889);  12,  256  (1891). 

-  For  details  on  the  symmetry  relations  in  enantiomorphous  forms  consult  the  works 
of  Th.  Liebisch :  Grundriss  der  physikalischen  Krystallographie,  Leipzig,  1896. 
P.  Groth  :  Physikalische  Krystallographie,  3  Aufl.,  Leipzig,  1895. 


8  CLASSIFICATION   OF    ACTIVE   SUBSTANCES 

the   nomenclature    of  Liebisch,    and    also    that  of  Groth   in 
parenthesis. 

/.     Regular  System. 

1.  Plagihedral-hemihedral  (pentagon-icositetrahedral)  group. 

2.  Tetartohedral  (tetrahedral-pentagondodecahedral)  group. 

II.     Hexagonal  System. 

3 .  Trapezohedral-hemihedral  ( hexagonal- trapezohedral )  group. 

4.  First hemimorph-tetartohedral( hexagonal-pyramidal) group. 

5.  Trapezohedral- tetartohedral  (trigonal- trapezohedral)  group. 

6.  Octahedral  (trigonal-pyramidal)  group. 

///.      Tetragonal  System. 

7.  Trapezohedral-hemihedral  (trapezohedral)  group. 

8.  Hemimorph-tetartohedral  (pyramidal)  group. 

IV.  Rhombic  System. 

9.  Hemihedral  (bisphenoidal)  group. 

V.  Monoclinic  System. 

10.  Hemimorphic  (sphenoidal)  group. 

VI.      Triclinic  System. 

11.  Hemihedral  (asymmetric) group. 

In  all  cases  in  which  a  complete  determination  of  the 
crystalline  symmetry  of  the  bodies  under  consideration  could 
be  carried  out  the  statement  made  above,  that  optical  rotation 
in  a  crystal  is  always  associated  with  enantiomorphism,  has 
been  confirmed.1  As  experience  has  shown,  this  rule  is  not 
reversible  ;  that  is,  if  the  crystals  of  a  body  are  found  to  be 
hemihedral  the  conclusion  can  not  be  drawn  that  in  either  the 
solid  or  dissolved  form  it  will  show  circular  polarization.  For 
example,  the  following  compounds  crystallize  in  hemihedral 
forms,  NH4C1,  Ba(NOs)2,  Li2SO4  +  HfO,  NiSO4  +  6H2O, 
Sr(CHO,),  -f-  2H2O,  but  they  are  inactive  in  solid  form  as 
well  as  in  solution.2 

1  I.iebisch  :  I/x:.  cit.,  p.  41  and  426. 

»  Objections  to  Pasteur's  law  have  been  raised  by  Wyrouboff  :  Ann.  chim.  phys. 
[6],  8,  416;  [7],  i,  10.  Also  by  Walden  :  Ber.  d.  chem.  Ges.,  39,  1692.  Traube 
replied  to  this  :  /bid.,  39,  2446. 


OPTICALLY    ACTIVE    CRYSTALS  9 

Optically  active  substances  may  be  divided  into  three  essen- 
tially distinct  classes : 

6.  First  Class. — Bodies  which  possess  the  property  of  rotating  the 
plane  of  polarized  light  only  in  the  crystallized  condition,  and  which 
lose  this  property  when  brought  into  the  amorphous  condition  by 
fusion  or  solution. 

Circular  polarization  has  been  noticed  only  in  crystals 
belonging  to  the  regular,  hexagonal,  and  tetragonal  systems  ; 
that  is,  in  groups  i  to  8  of  the  above  scheme.  At  present  the 
following  organic  and  inorganic  bodies  are  known  to  belong 
here  : 

Regular  System. 
f  Sodium  chlorate NaClO3. 

Group  2 J  Sodium  bromate XaBr03. 

Sodium  sulphantimonate Na3SbS4  -f  9H2O. 

[  Sodium  uranyl  acetate NaUO2(C2H3O2  )3? 

Hexagonal  System. 

f  Potassium  lithium  sulphate KLiSO4. 
Ammonium  lithium  sulphate (NH4)LiSO4. 
Rubidium  lithium  sulphate RbLiSO4. 

(^  Potassium  sulphate  lithium  chromate K2SO4  -f-  Li2CrO4. 

f  Quartz SiO,. 

Cinnabar HgS. 

Potassium  dithionate K2S2O6. 

Rubidium  dithionate Rb2S2O6. 

Calcium  dithionate CaS2O6  —  4H2O. 

Strontium  dithionate SrS2O6  -f-  4H2O . 

Lead  dithionate PbS2O6  +  4H2O. 

Benzil C6H5.CO.CO.C6H5. 

(Rubidium  and  cesium  tartrates,  laurel  camphor,  and  matico-camphor 
belong  to  Class  II. ) 

Group  6  \  Sodium  periodate NaIO4  -[-  3H2O. 

Tetragonal  System. 

f  Ethylene   diamine  sulphate (N2H4.C2H4)H2SO4. 

I  Guanidine  carbonate (CH5N3)H2CO3. 

Group  7  \  Diacetyl   phenolphthalein C20H12(  C2H3O2)2O4 

I  Sulphobenzene  trisulphide ( C6H5.SO2.S)2S. 

[  Sulphotoluene  trisulphide 

(Strychnine  sulphate  belongs  in  Class  II.) 


Group  5 


10 


CLASSIFICATION    OF   ACTIVE   SUBSTANCES 


The  optically  active  single-refracting  crystals  belonging  to 
the  regular  system  show  rotation  of  the  plane  of  polarization 
equally  strong  in  all  directions,  as  was  shown  especially  by 
Sohncke,1  in  the  case  of  sodium  chlorate.  In  the  cases  of 
hexagonal  and  tetragonal  crystals,  which  are  uniaxially  double- 
refracting,  the  phenomenon  of  circular  polarization  may  be 
observed  only  in  the  direction  of  the  optical  axis,  and  plates 
for  this  purpose  must  therefore  be  cut  perpendicularly  to  this 
axis.  In  normal  biaxial  crystals  belonging  to  the  rhombic, 
monoclinic  and  triclinic  systems  the  rotating  power  has  not  yet 
been  observed,  and  as  Wiener2  has  shown,  it  cannot  be  found  in 
all  those  cases  where  there  is  at  the  same  time  strong  double 
refraction. 

All  the  active  crystals  which  have  been  mentioned  above 


Fig.  i. 


Fig.  2. 


occur  in  right-  and  left-rotating  varieties,  which  exhibit  equal 
activities  for  equal  thicknesses  of  layers  passed  by  the  light. 
The  direction  of  rotation  stands  in  relation  to  the  condition  of 
enantiomorphism  in  the  crystal,  which  is  often  shown  in  the 
geometric  development  of  the  latter  by  the  appearance  of 
so-called  hemihedral  or  tetartohedral  surfaces,  oppositely 
located  in  different  individual  crystals.  The  best  known  illus- 
tration of  this  is  found  in  hexagonal,  trapezohedral-tetarto- 
hedral  quart/.,  in  which  the  tetartohedral  surfaces,  s  and  x, 
very  often  appear,  and  in  such  a  manner  that  in  right-rotating 
Mis  CFig.  2),  the  surface,  s,  lies  to  the  right  of  x,  while  in 
left-rotating  crystals  ( i'\K.  i ) ,  it  lies  to  the  left  of  x.  The  one 

1  Sohncke:   Wit-d.  Ann.,  3,  530. 
•  Wiener:  Wied.  Ann.,  35,  i. 


OPTICALLY    ACTIVE    CRYSTALS  II 

form  is  the  mirror  image  of  the  other.     Analogous  relations 
are  found  in  other  crystals  of  the  class.1 

The  extent  of  rotating  power,  for  equal  thicknesses  of  layer 
passed  by  the  light,  is  very  different  in  different  active  crystals. 
The  following  table  gives  the  data  thus  far  found  for  plates 
of  i  millimeter  thickness,  and  for  light  of  different  wave 
lengths.  The  latter,  expressed  in  millionths  of  a  millimeter 
(jUA*),  correspond  either  to  the  Fraunhofer  lines,  C,  D,  E,  F, 
G,  to  mean  yellow  light,/,  or  to  the  lines  from  lithium,  sodium, 
and  thallium.  The  bodies  are  arranged  in  the  order  of  their 
rotating  power  for  the  line  D.2 

Crystalline  mixtures  of  isomorphous  active  crystals  exhibit 
a  rotation  which  is  nearly  proportional  to  the  percentage  com- 
position and  amount  of  rotation  of  the  components.  The 
proof  of  this  rule  has  been  given  mainly  by  Bodlander3  from 
investigations  of  various  crystallizations  of  lead  dithionate 
and  strontium  dithionate. 

Behavior  of  active  crystals  in  pou'dered  condition.  —  The  ques- 
tion as  to  whether  the  rotating  power  of  fine  particles  is  the 
same  as  that  of  the  larger  crystal,  or  whether  it  decreases 
when  the  particles  have  reached  a  certain  degree  of  fineness 
has  been  tested  by  Landolt*  wTith  sodium  chlorate. 

In  crystalline  plates  i  millimeter  in  thickness  the  salt  shows 
a  rotation  for  white  light,  ctj  =  ±  3.54°,  and  as  its  specific 
gravity  is  d  -  2.488  the  specific  rotation  must  be 
\_a~]j  —  a/d  =  =b  1.42°.  If  the  crystals  are  rubbed  as  fine  as 
possible  and  the  powder  so  obtained  be  suspended  in  a  mixture 
of  absolute  alcohol  and  carbon  disulphide,  the  composition  of 
which  may  be  varied  until  a  clear  liquid  is  obtained,  that  is, 
until  the  mixture  has  the  same  refractive  index  as  the  salt 
particles,  then  it  is  found  on  examination  in  a  polarization  tube 

1  All  these  cases  are  discussed  in  the  works  of  Groth  and  I,iebisch,  already  referred 
to. 

-  Besides  these  the  following  observations  have  been  made  which  refer  to  green 
light  not  specially  denned  : 


Full  data  are  given  for  quartz  and  sodium  chlorate  in  the  chapter  on  "Rotation 
Dispersion." 

3  Bodlander  :  Inaug.  Diss.  Breslau,  iSSa  ;  Wied.  Beib.,  7,  396. 

4  Landolt  :  Sitzungsber.  der  Berl.  Akad.,  1896,  785  ;  Ber.  d.  chem.  Ges.,  29,  2404. 


12  CLASSIFICATION   OF    ACTIVE   SUBSTANCES 

(i  to  1.5  decimeter  in  length)  that  the  suspended  substance 
shows  the  right  or  left  rotation  of  the  original  crystals.  In 
order  to  keep  the  powder  evenly  distributed  through  the  liquid 
it  is  necessary  to  rotate  the  polarization  tube  on  its  axis.  In 
such  experiments  in  which  the  diameters  of  the  particles  were 
mostly  between  0.004  mm.  and  0.012  mm.  or  even  between 
0.003  and  0.007  mm-  ^e  specific  rotation1  was  found  as 
[a]y  =  =fc  1.36°  to  1.49°,  or,  in  the  mean,  ±  1.41°,  referred 
to  a  layer  i  mm.  in  thickness.  As  this  value  agrees  exactly 
with  that  found  for  the  large  crystals  it  follows  that  in 
powdering  to  the  degree  mentioned  the  active  crystalline 
structure  has  not  suffered  the  slightest  change.  The  question, 
what  size  the  smallest  particle  which  still  shows  circular  polar- 
ization must  have,  and  of  how  many  single  molecules  it  must 
be  composed,  remains  unanswered. 

The  optical  activity  of  sodium  chlorate  disappears  completely 
in  aqueous  solution,  and  even  when  this  is  in  supersaturated 
condition.  If  the  salt  be  precipitated  by  addition  of  alcohol, 
the  crystalline  precipitates  formed,  and  from  solutions  of  either 
right  or  left  rotating  crystals,  are  found  to  be,  when  examined 
in  the  suspended  condition,  either  inactive  or  to  show  one  of 
the  two  directions  of  rotation.  The  specific  rotation  is, 
however,  always  smaller  than  the  normal  (  zb  1.41°),  from 
which  it  follows  that  the  precipitates  are  mixtures  of  right  and 
left  salts.  Which  of  these  predominates  depends  on  the  direc- 
tion of  rotation  of  the  particles  which  first  separate.  Bearing 
on  this  it  may  be  said  that  when  one  of  two  portions  of  a 
saturated  solution  is  treated  with  a  trace  of  the  solid  right- 
rotating  salt,  and  the  other  with  a  trace  of  the  left-rotating 
salt  and  then  precipitated  by  alcohol,  the  precipitates  formed 
are  found  to  rotate  accordingly. 

On  the  cause  of  rotation  in  crystals  see  §§9  and  10. 

1  The  specific  rotation  of  solid  active  particles  is  expressed,  as  in  the  case  of  solu- 
tions by  [a]  =  or///,  when  a.  is  the  angle  of  rotation,  /the  length  of  tube,  v  the  volume 
of  the  same  and  /  the  weight  of  the  powder  suspended. 


OPTICALLY   ACTIVE   CRYSTALS 


_  -s^S-£  = 

fo  OJ     *"1    ^.  £jj 


*  i  2.8   £~  3« 

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S>^s?£ 

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S  ?^*M  3  SS  o 

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139,  224 
157,  122 
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:  tf  ; 


.      Os^J    .     W 


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14  CLASSIFICATION   OF   ACTIVE   SUBSTANCES 

7.  Second  Class. — Bodies  which  rotate  in  both  crystalline  and 
amorphous  form,  in  solution  or  in  fused  condition. 

But  six  compounds  of  this  class  are  known  : 

Matico  camphor,  Rubidium  tartrate, 

Patchouli  camphor,  Cesium  tartrate, 

Laurel  camphor,  Strychnine  sulphate.1 

It  is  interesting  to  compare  in  these  substances  the  rotation 
in  the  crystalline  form  with  that  shown  by  an  equally  thick 
plate  of  the  amorphous  compounds  (H.  Traube).  In  the  last 
case  the  action  of  the  single  molecules  alone  comes  into  play, 
while  in  the  other  the  effect  of  a  particular  crystalline  structure 
is  to  be  added  to  this.  In  this  second  case  the  molecular  rotation 
and  crystalline  rotation  must  be  added  together,  or,  if  they  have 
opposite  directions  they  may  partially  neutralize  each  other. 

The  following  observations  have  been  made  on  these  sub- 
stances : 

Matico  camphor.  C^H.^O.* — The  rotation  of  the  hexagonal 
trapezohedral-tetartohedral  crystals  was  discovered  by  Hintze3 
and  measured  by  him,  and  also,  later  by  H.  Traube.4  The 
following  angles  were  measured  for  a  plate  i  mm.  in  thickness: 

Hintze  :  au  =    -  1.68°,  «Na  -    -  2.07°,  <*T,  =    —  2.47°. 
Traube:  aNa  =    -  1.81°,  —  1.96°,  —  1.86°. 
Mean,  an  =  —  1.92°. 

Right  rotating  crystals  have  not  yet  been  found. 

H.  Traube5  has  measured  the  rotating  power  of  the  sub- 
stance, which  melts  at  94°,  in  the  liquid  condition,  in  a  tube 
i  decimeter  in  length  and  at  different  temperatures,  as  follows  : 

Temp.  Rotation  for  Sp.  gr.  at  t°.  Specific  rotation. 

T.  i  dm.  aD  d\.  WP. 

108°  —26.29°  0-924  —28.45 

H5  —25.59  0.901  —28.40 

126  —24.74  0.874  —28.32 

135  —23.86  0.845  —28.24 

i  Recently  W.  J.  Pope  (J.  Chem.  Soc.,  69,  971)  has  added  two  bodies  to  this  list. 

These  are  d»-?r-camphanic  acid,  O.C8Hi,<f  ,  and  transcamphotricarboxylic  acid, 

CfHn  (COOH)8.  described  by  Kipping  :  J.  Clu-m    Soc.,  69,  943  and  950.     Data  concern- 
ing the  amount  of  rotation  are  not  yet  given 
xler :  Her.  d.  chem.  Ges.,    16,  2841. 

*  Hintze:  Pogg.  Ann.,  157,  127  (1876). 

4  Traube:  Sitzber..  d.  Berliner  Akad.,  i,  195  (1895). 

*  H.  Traube:  Groth's  Ztachr  f   Kryst.,  aa,  I,  47. 


OPTICALLY    ACTIVE    COMPOUNDS  15 

From  the  change  in  specific  rotation  with  increasing  tempera- 
ture the  specific  rotation  for  the  ordinary  temperature  (20°), 
may  be  calculated  as  approximately  \_(*]D  -  -  29.1°,  Traube 
obtained  almost  the  same  value;  that  is,  —  28.7°,  from  obser- 
vation of  a  10  per  cent,  chloroform  solution  of  the  camphor. 
If  we  take  [#]  D  =  -  29°  this  represents  the  angle  of  rotation 
of  a  column  of  the  amorphous  camphor  100  mm.  in  length 
and  having  the  ideal  density  of  i  .  If  we  reduce  the  rotation 
of  the  crystalline  camphor,  with  a  density  of  1.08  at  15°,  to 
the  same  standard  we  have  : 


> 
i.  08 

The  angle  of  rotation  of  the  amorphous  and  crystalline  sub- 
stances are  related  thus  as  29  :  178  ;  and  if  we  assume  that  in 
the  last  number  the  molecular  rotation  is  included,  the  part 
due  to  the  crystalline  structure  must  be  178°—  29°  =  149°.  It 
follows  therefore  that  the  rotatory  polarizing  behavior  of  the 
crystals  is  about  ^  due  to  the  molecular  rotation  and  f  to  the 
crystalline  rotation. 

Patchouli  camphor,  C15H26O.  —  The  optical  rotation  of  the 
hexagonal  crystals,  first  noticed  by  v.  Seherr-Thoss1  was 
measured  by  H.  Traube,2  who  found  a  rotation  of  OLD  =  —1.325° 
for  i  mm.  Montgolfier3  found  \of}D  =  -  118°  as  the  specific 
rotation  of  the  fused  substance  at  59°  (corresponding  to  about 
—  1  1  8  .  3  °  for  the  ordinary  temperature  )  .  From  alcoholic  solution 
in  which  the  rotation  decreases  with  the  dilution  he  derived 
the  value,  [ct]^  —  —  124.5°  for  the  pure  substance.  From 
these  two  values,  by  taking  the  specific  gravity  as  1.051, 
according  to  Gal4  (for  the  crystals),  the  rotation  of  a  layer  i 
mm.  thick  is  calculated  as  txD  =  1.24  and  1.31,  which  values 
agree  very  well  with  that  observed  in  the  crystals  ;  viz.,  1.325. 
We  have  here  a  case  in  wrhich  the  crystalline  rotation  coincides 
nearly  with  the  molecular  rotation,  and  one  therefore  in  which 
the  effect  of  the  first  is  scarcely,  if  at  all,  perceptible. 

Laurel  camphor,  C10H16O.  —  The  crystals,  according  to 
H.  Traube,  hexagonal  trapezohedral-tetartohedral,  show,  by 

1  Private  communication. 

-  H.  Traube  :  Sitzungsber.  der  Berliner  Akad.,  i,  195  (1895). 

3  Montgolfier:  Bull.  soc.  chim.  [2],  a8,  414  (1877). 

4  Gal:  Ztschr  Chem.,  220  (1869). 


1 6  CLASSIFICATION   OF   ACTIVE   SUBSTANCES 

the  measurements  of  v.  Seherr-Thoss1  a  right  rotation  as 
follows,  for  a  plate  of  i  mm.  thickness  : 

White  light.  Ray  B.  Ray  D.        Transition  tint.  Ray  G. 

0.875°  0.455°  0-65°  0.73°  1.818° 

From  solutions  of  the  camphor  in  different  liquids  the  maxi- 
mum specific  rotation  of  the  pure  amorphous  substance  is 
found  to  be  \_oi]D-  -f-  55.5°  ;2  therefore,  if  the  specific  gravity 
be  taken  as  0.998,  the  same  as  for  the  crystallized  camphor, 
the  angle  of  rotation  for  a  layer  of  i  mm.  thickness  is  found 
to  be  [«]/>  = :  -f  0.55°.  This  value  is  but  little  lower  than  that 
found  for  the  crystals,  aD  =  -f  0.65°,  from  which  it  follows 
that  the  activity  of  the  latter  appears  to  depend  almost  wholly 
on  the  molecular  rotation. 

Right  and  left  rubidium  tartrate,  Rb2C4H4O6. — According  to 
H.  Traube  both  salts  are  hexagonal  trapezohedral-tetarto- 
hedral.  As  Wyrouboff3  found  and  Traube4  later  the  crystals 
formed  from  ordinary  d-  tartaric  acid  are  left  rotating,  while 
those  from  /-  tartaric  acid  are  right-rotating.  They  observed 
for  plates  of  i  mm.  thickness : 

d-Acid  salt.  /-Acid  salt. 

Wyrouboff (*D  —    -10.7°  flf^  — -f  10.5° 

Traube -10.24  +10.12 

If  the  left-rotating  crystals  be  dissolved  in  water  the  solu- 
tion shows  right  rotation  and  vice  versa.  The  specific  rotating 
power  is  diminished  with  increasing  dilution,  and  at  a  rate 
which  is  shown,  according  to  Rimbach,5  by  this  formula, 
derived  for  the  right  rotating  salt 

O]£°  =a  +  25.63°  -0.06123  ?, 

in  which  q  represents  the  percentage  amount  of  water  present. 
This  formula  was  derived  from  observations  on  solutions  con- 
taining up  to  64.5  per  cent,  of  the  salt,  and  the  constant, 
25.63,  may  therefore  be  taken  as  satisfactorily  representing  the 
specific  rotation  of  the  amorphous  anhydrous  substance. 
Using  with  this  the  known  specific  gravity  of  the  crystallized 

v.  Seheir  Thoss  :  Ztachr.  fur  Kryst.,  33,  583  (1894). 

»  Mean  of  the  determinations  of  I^andolt  :  Ann.  Chem.  (Liebig),  189,  332,  and  Rim- 
bach:  Ztvrhr.  i»hys.  Chem.,  9,  698. 

3  Wyrouboff  :  Jour,  de  physik.  [3],  3,  451  (1894). 

«  H    Tr.ui>..      Sitzungsber.  der  Berliner  Akad..  i,  195  (1895). 

•  Rimbach  :  Ztschr.  phys.  Chem.,  16,  671  (1895). 


OPTICALLY   ACTIVE   CRYSTALS  17 

salt,  d  =  2.694,  we  obtain  the  rotation  of  a  plate    i   mm.  in 
thickness  from 

aD  =  0.2563  X  2.694  =  +  0.69. 

Regarding  the  phenomenon  that  the  crystals  show  a  rotation 
opposite  in  direction  from  that  of  the  solutions  it  may  be  said 
that  this  depends  on  the  activity  of  the  molecules.  It  is  well 
known  that  with  many  substances  the  direction  of  rotation  is 
dependent  on  the  concentration  of  their  solutions.  For 
example,  malic  acid,  sodium  malate  and  barium  malate  show  a 
negative  rotation  in  dilute  solutions  which  decreases  with 
increasing  concentration,  becomes  zero  (for  malic  acid  in  34 
per  cent,  solution)  and  then  goes  over  into  a  right-hand  rota- 
tion. This  would  remain  if  the  substances  were  finally  brought 
to  the  solid  condition.  The  same  phenomenon  is  exhibited  by 
solutions  of  </-tartaric  acid,  the  specific  rotation  of  which  is 
given,  according  to  Th.  Thomsen,1  by  this  formula  : 

[or]g  =  —  1.265  4-0.1588?. 

According  to  this  the  point  of  inactivity  is  reached  in  a  solu- 
tion with  8  per  cent,  of  water  and  the  solid  substance  would 
show  left  rotation,  as  Biot2  indeed  found.  The  alkali  tartrates, 
however,  do  not  show  this  change  of  rotation,  and  also  for  the 
rubidium  salt  of  dextrotartaric  acid  it  is  evident  from  the 
above  formula  of  Rimbach  that  even  in  the  most  concentrated 
solution  or  in  dry  condition  it  can  not  exhibit  left-hand  rotation. 

As,  therefore,  the  activity  of  the  molecules  produces  no 
change  in  the  direction  of  rotation,  it  follows  that  in  the  struc- 
ture of  the  crystals  must  be  found  the  reason  why  these  rotate 
oppositely  from  their  solutions.  Consequently  it  may  be 
assumed  that  in  the  case  of  the  rubidium  salt  of  ^-tartaric 
acid  the  observed  rotation,  aD  =  --  10.24°,  is  compounded 
from  the  molecular  rotation,  aD  =-.  -f-  0.69°.  and  a  crystalline 
rotation  amounting  to  aD  =  -  10.93°.  The  crystalline  rota- 
tion would,  therefore,  be  about  sixteen  times  as  great  as  the 
molecular. 

Strychnine  sulphate,  (C21H22N2O2)2.H2SO4.6H2O.— In  the 
tetragonal  crystals  rotation ,  left-handed,  was  first  observed  by 

1  Thomsen  :  J.  prakt.  Chem.  [2],  32,  213. 
-  Biot :  Ann.  chim.  phys.  [3],  28,  351. 
2 


1 8  CLASSIFICATION    OF    ACTIVE   SUBSTANCES 

Des  Cloizeaux.1  H.  Traube2  found  aD  =  -  13.25  for  i  mm. 
The  solutions  are  also  left-rotating.  According  to  WyroubofF 
strychnine  sulphate  is  not  a  true  circularly  polarizing  sub- 
stance. It  may  be  obtained  in  two  forms,  of  which  one  is 
quadratic  and  optically  inactive,  while  the  other  is  built  up  of 
layers  of  clinorhombic  plates.  Light  passing  through  these 
last  crystals  is  partially  elliptically  polarized. 

Further,  amylamine  alum  would  belong  also  in  the  group  if 
the  statement  of  LeBel*  is  correct  that  it  shows  rotation  in 
crystallized  and  dissolved  form.  But  according  to  Wyrouboff5 
while  the  crystals  show  anomalous  double  refraction  they  are 
not  circularly  polarizing. 

Finally  it  must  be  remarked  that  circular  polarization  should 
be  expected  in  all  those  optically  uniaxial  and  regular  crystals 
of  substances  which  exhibit  molecular  rotation.  The  reason 
why  this  has  been  observed  in  but  few  cases  up  to  the  present 
time  may  be  found  in  the  fact  that  the  rotating  power  of  many 
bodies  is  too  small  to  be  detected  in  crystal  plates,  to  which, 
on  account  of  the  necessary  homogeneity  and  transparency, 
only  a  slight  thickness  can  be  given.  In  conine  aluminum 
alum  (C8H17N)rH2SO4  -f-  A12(SO4)3  +  24H2O,  and  in  conine 
iron  alum  (C8H17N)2.HaSO4,  +  Fe2(SO4)3  -f  24H2O,  which 
both  crystallize  regularly  tetartohedral,  H.  Traube6  could 
find  no  evidence  of  circular  polarization,  even  when,  by  piling 
up  clear  octahedra,  layers  of  i  to  3  cm.  were  obtained.  In 
aqueous  solution,  however,  optical  activity  was  present, 
although  small ;  for  the  aluminum  salt,  with  c—  46,  [<*]/>  = 
-f  0.70°  and  for  the  iron  salt,  with  c  =  66.8  [tx~\D  =  -[-0.53° 
were  found. 

8.  Third  Class. — Bodies  which  are  active  only  in  amorphous  con- 
dition (natural  liquids  or  solutions). 

The  substances  of  this  class  are  carbon  compounds  exclu- 
sively ;  no  inorganic  substances  are  known  which  belong  here. 
The  following  tables  give  a  general  summary  of  the  active 

DCS  Cloizeaux  :  Pogg.  Ann.,  102,  477  (1857). 

H.  Traube  :  Lamlolt-Boernstein's  phy».  chem.  Tab.,  and  Ed.  p.  460. 

Wyrouboff:  Bull.  Soc.  Min.,  7,  10  (1884). 

Ix:  Bel:  Ber.  d.  chem.  Ges.,  5,  391  (1872). 

Wyrouboff:  Ann.  chim.  phys.  [61,  8,  340  (1886). 

H.  Traube:  N.  Jahrb.fur  Min.,  Beil.,  y,  625. 


ACTIVE   ORGANIC    COMPOUNDS  1 9 

organic  compounds  with  their  optical  modifications.  Of  the 
last  the  right-rotating  are  designated  by  -j-,  the  left-rotating 
by  — ,  the  racemic  bodies,  which  may  be  split  into  their  anti- 
podes, by  r,  and  the  inactive  forms,  which  can  not  be  split  up 
by  i.  The  letter  i  is  used  also  with  some  inactive  bodies  of 
unknown  constitution,  which  on  account  of  the  connection  are 
grouped  with  other  substances.  In  the  symbols,  d(-\-},  d( — ), 
/(-}-),  /(  — ),  d  and  /  indicate  the  derivation  from  a  right- or 
left-rotating  parent  substance,  while  -f-  and  —  indicate  the 
direction  of  rotation. 

For  those  bodies  which  have  been  studied  in  solution  the 
solvent  is  mentioned,  because  this  sometimes  exerts  an  influ- 
ence on  the  direction  of  rotation. 


W  =  water. 

A  —  alcohol. 

E  =  ether. 

Ac  —  acetone. 


B  =  benzene. 

C  =  chloroform. 
Aa  =  acetic  acid. 
Bo  =  borax. 


/  indicates  that  the  body  is  in  itself  a  liquid. 

As  far  as  space  permits  the  constitutional  formulas  of  the 
substances  are  given  and  in  a  manner  which  will  indicate  the 
asymmetric  carbon  atom,  and  that  is  by  placing  the  four 
groups  connected  with  it  in  parentheses. 

The  data  on  specific  rotations  will  be  given  later  in  the 
section  on  constants  of  rotation. 


i.  Hydrocarbons. 

Methylethylpropylmethane;  (C3H7)(C2H5)C(H)(CH3)  ••    / 
Diamyl,(C2H5)(CH3)(H;C(CH2-CH2)C(H)(CH3)(C2H5)  / 
Phenylamyl,  (C6H5CH2)(C2H5)C(CH3)(H)  ...........    / 

Isobutylamyl,  (C2H5)(CH3)C(H)(C4H9)  ...............    / 

Ethylamyl,  (C2H5)(CH3)C(H)(C2H5)  .................    / 


2.  Monohydric  Alcohols  and  Derivatives. 

Methylethylcarbinol,  (C2H5)(CH3)C(H)(OH)  .......... 

Derivatives  :  chloride,  iodide  .................... 

Amyl  alcohols  : 
Methylethylcarbincarbinol  ,  common  active  amyl  alcohol, 

(C2H5)(CH3)C(H)(CH2OH)  ..........  .............. 


•f 


20 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


Derivatives:  (a)  From  /-amyl  alcohol :  chloride,  bro- 
mide, iodide,  cyanide,  sulphydrate, 

thiocyanate,    ether,    ester,   amylsul-  ^     -f- 

phuric   acid,  diamylamine,  triamyl-  i 

aniine  and  salts  of  amylamine J 

Amyl  amine 

(d)  From  </-amyl  alcohol  :  iodide f 

Methylpropylcarbinol,  (C3H7)(CH3)C(H)(OH) /          —  r 

Derivatives :  From  the   /-alcohol  :   chloride,    iodide  f 

Acetin,  propin,  butyrin f 

Hexyl  alcohols : 
Methylethylpropyl      alcohol,      (C2H5)(CH3)C(H)(CH2 

CH2OH) / 

Ethylpropylcarbinol,  (C3H7)(C2H5)C(H)(OH) /   +          r 

Derivatives  :  Chloride f 

Iodide / 

Methylbutylcarbinol,  (C4H9)(CH3)C(H)(OH) / 

Methylamylcarbinol,  (C5Hn)(CH3)C(H)(OH) /    +          r 

3.  Dihydric  Alcohols  and  Derivatives. 

Propyleneglycol,  (CH3)(H)C(OH)(CH2OH) - r 

Derivatives  :  From  /-propyleneglycol :  propylene- 

oxide f 

Diacetin,  mono-  and  dichlorhydrin, 

Chlorbromhydrin f   _[_ 

Chloracetin,  chlorbutyrin f 

Diphenylglycol  :  r 

Derivative   :     Diphenylethylenediamine,      [(C6H5) 

(NH2)(H)C]2 £    +  -  r 

4.   Trihydric  and  Tetrahydric  Alcohols  and  Derivatives . 
No  optically  active  compounds  are  known. 

5.  Pentahydric  Alcohols. 

Arabitol,  C5H12O5 W+  Bo 

Xylitol,  C5H1205 W(  +  Bo)    +? 

Adonitol,  C5H1205 W  (  +  Bo) 

Rhamnitol,  C6HUO5 

Quercitol,  CeH12O5  (cyclic) 

6.  Hexahydric  Alcohols. 

rf-Mannitolf  CeH14O6 W 

W  -f-  Bo  and  other  salts          -f 

alkalies 
/-Mannitol,  C$HUO6 W  +  Bo 


ACTIVE   ORGANIC   COMPOUNDS 


21 


Derivatives  :  From^-mannitol,isomannitol  ( 

/3-mannitol  (  W) ,  hexaacetate 
hexachloride  (B) + 

Mannitoldichlorhydrin  (  W} 

rf-Sorbitol,  C6HUO6 W 

W+Bo,  alkalies    + 

/-Sorbitol,  C6HU06 W  +  Bo 

rf-Iditol,  C6HU06 W 

/-Iditol  C6HU06 W 

Dulcitol,  QHnOg W 

Talitol ,  C6HU06 W 

Rhamnohexitol,  C7H16O6 W 

rf-Inositol,  QH^Oe  (cyclic) W 

Hexaacetate A 

/-Inositol W 

Hexaacetate A 

/-Inositol W  r 

Bornesitol,  methyl  inositol,  C7HUO6  (cyclic) W    + 

Pinitol,  C-HUO6  (cyclic) W    -f 

Quebrachitol,  C7HUO6  (cyclic) W 

•j.  Heptahydric  Alcohols. 

Volemitol,  C-H16O7 W 

a-Glucoheptitol,  C7Hi6O7 W 

a-Galaheptitol,  C7H16O7 W     ?     ? 

</-Mannoheptitol,  C7H16O7 W 

W  -  Bo    - 

/-Mannoheptitol,    C7H16O7 W 

/-Mannoheptitol,   C7H16O- W  r 

8.  Octahydric  Alcohols. 

^-Mannooctitol,  C8HldO8 W     ? 

/-Glucooctitol,  C8H1808 W' 

9.  Nonahydric  Alcohols. 
Glucononitol,  C9H20O9 ? 

10.  Acids  with  Two  Atoms  of  Oxvgen,  and  Derivatives. 

Valeric  acid,  (C2H3)(CHS)C(H)(COOH) /   _j_ 

Derivatives  :  From  (/-valeric  acid  :  ester,  valeralde- 

hyde,  valeryl  chloride /    _ 

Caproicacid,  (C2H5)(CH3)C(H)(CH2COOH) / 

Derivative  :  Hexylester f   _j_ 

ii.  Acids  with   Three  Atoms  of  Oxygen  and  Derivatives. 
Ethylidene  lactic  acid,  (CH3)(H)C(OH)(COOH) W 


22 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


Derivatives:  From  </-(sarco) lactic  acid:  salts,  esters, 

anhydride  (alanin  ?) W 

From  /-lactic  acid:  salts,  esters,  anhy- 
dride      W    + 

o-Oxybutyric  acid,   (C2H5)(H)C(OH)(COOH) W    + 

0-Oxybutyric  acid,  (CH3)(H)C(OH)(CH2COOH) W 

Phenylglycolic  acid,  (C6H5)(H)C(OH)(COOH) W    + 

Isopropylphenylgly  colic      acid,       (  C6H5 )  ( C3H7 )  C  ( O  H  ) 

(COOH) W    + 

Tropic  acid,  (C6H5)(H)C(CH2OH)(COOH) W    + 

a-Amido    propionic    acid,     alanin,     (CH3)(H)C(NH2) 

(COOH) W 

Phenyl-o-amidopropionic    acid,     (CH3)(H)C(NHC6H5) 

(COOH) W 

o-Amidocaproic        acid,      leucine,      (C4H9)(H)C(NH2) 

(COOH) W    +   —  r 

acids  or  alkalies  ~f- 

Derivatives  :  Phthalylleucine,  leucinephthalic  acid •  —  r 

Cystin,  (CH3)(SH)C(NH2)(COOH) W,  HC1 

Derivatives:  Phenyl  cystin,    (CH3)(C6H5S)C(NH2) 

(COOH ) W,  NaOH 

Bromphenyl  cystin W,  NaOH 

Phenyl  mercapturic      acid,        (CH3)— 
(C6H5S)C-(NHCOCH3)(COOH)...    A 

Bromphenyl  mtrcapturic  acid A 

Sodium  salt  of  same W 

Oxyphenyl     alanin,       tyrosin,       (HO.C6H4.CH2)(H)C 

(NH2)(COOH) W,  NaOH,  HC1    A r 

Parasorbic  acid,  (C2H5)(H)C(O)(CH=CH—  CO) ;.    /    -f 

Ricinoleic  acid,  (C6H13)(H)C(OH)(CH.C.C8H16.COOH) 

Ricinelaidic  acid,  (isomeric  with  ricinoleic  acid) Ac,  A 

Ricinstearolic  acid,  Cj-Hso.OH.COOH Ac    -+- 

1 2.  Acids  with  Four  Atoms  of  Oxygen  and  Derivatives. 

Pyrotartaric  acid,  (CH3)(H)C(COOH)(CH2.COOH). . .   W    -\ r 

Glyceric  acid,  (CH,OH)(H)C(OH)(COOH) W 

I  u-rivatives:  Salts  and  esters  of  the  </-acid W 

Phenyl-a-bromlactic  acid,  (C<H5)(H)(OH)C— C(Br)(H; 
(COOH) w 

Phenyloxyacrylic  acid,  (C6H5)(H)(O)C— C(O)(H) 
(COOH),  salts #/ 

Phenyldibrompropionic  acid,  cinnamic  acid  dibromide, 
(C.H5)(H)(Br)C-C(Br)(HKCOOH) A 

Phenyldibrombutyric  acid,  (C,H5)(H)(Br)C— C(Br) 
(H)(CH2COOH) A 


ACTIVE    ORGANIC    COMPOUNDS 


13.  Acids  -with  Five  Atoms  of  Oxygen  and  Derivatives. 
Trioxybutyric   acid,    (CH2OH)(H)(OH)C— C(H)(OH) 

(COOH) W 

Shikiminic  acid,  C7H10O5  (cyclic) A 

Derivatives:  Triacetyl,  propionyl,  butyryl  esters,  hy- 
droshikiminic  acid,  dibromshikiminic 

acid W 

Bromshikiminic  acid  lactone W 

Dioxyhydroshikiminic  acid W 

Malic  acid,  (H)(OH)C(COOH)(CH2COOH) W 

^/-Malic  acid,  according  to  concentration W 

anhydrous 

/-Malic  acid,  (common  acid)  according  to  concen- 
tration     W 

anhydrous 
Derivatives:  Of  /-malic  acid:  malates,  esters,  amide- .   W 

Acetylmalic  acid W,  Ac 

Acetylmalic  acid  anhydride >f,  Ch 

Propionyl-,  butyrylmalic  acid,  and  an- 
hydride   Ch 

Methylmalic     acid,      (CH3)(COOH)(H)C— C(OH)(H) 

(COOH)   W 

Chlorsuccinic  acid,  (C1)(H)C(COOH)(CH2COOH) . . . .   W 
Methoxysuccinic       acid,       (CH3O)(H)C(COOH)(CH2 

COOH) W 

Ethoxysuccinic  acid W 

Urimidosuccinic     acid,      (H)(NH.CO.NH)C(CO)(CH2 

I J 

COOH)  W 

Uramidosuccinamide,       (H)  (CH2.CO.NH2)  C  (NH.CO. 

NH2) (COOH) W 

Asparticacid,  (H)(NH2)C(COOH)(CH2COOH) W 

Common   aspartic  acid,   in  alkaline  solution — ,    in 
acid  solutions  -}-. 

/3-Asparagin,  (H)(NH2)C(COOH)(CH2.CONH2) W 

/-Asparagin,   in   alkaline  solution  — ,   in   acid   solu- 
tion—.   ... 

Oxyglutaric  acid,  (H)(OH)C(COOH)(C2H4.COOH). . .   W 
Glutaminic  acid,  (H)(NH2)C(COOH)(C2H4.COOH) 

W,  acids 

{/-Acid W+  alkalies 

{/-Amide HC: 

Pyroglutaminicacid,  (H)(NH)C(C2H4CO)(COOH),  and 

amide W 

a-Isotrioxystearic  acid,  C17H32fOH)3COOH 


-r 


-r 


+ 


+ 


+ 


- 


+ 


- 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


14.  Acids  with  Six  Atoms  of  Oxygen  and  Derivatives. 

[The   aldehydes  of  these  monobasic  acids  are  described 

as  oxyaldehydes  (sugars)  below.] 

Tartaric  acid,  (COOH)(OH)(H)C— C(H)(OH)(COOH)  W    +   —  r 
Derivatives:  Of   </-tartaric   acid  :    neutral    and  acid 
salts,  esters,  methyl  and  ethyl  tartaric 

acid  salts,  tartratnide W    -\- 

•  Diacetyl  tartaric  acid  anhydride  and 
diethyl,  dipropyl  (Ac,  A],  dibutyl 
ester,  di-benzoyl  tartaric  acid  anhy- 
dride (Ac) 

Diacetyl  tartaric  acid  and  salts,  dia- 
cetyl  tartaric  acid  dimethyl,  diben- 
zoyl  tartaric  acid  hydrate,  dimethyl, 

diethyl,  and  dibutyl  esters. A 

Derivatives:  Of    /-tartaric     acid:   neutral  and  acid 

salts,  amide W 

Diacetyl  tartaric  acid  dimethyl  ester. . .  A    -f- 

Arabonic  acid,  C5H10O6 ;  lactone,  C5H8O5 W 

Ribonic  acid,  C5H10O6;  lactone,  C5H8O5 W 

Cadmium  salt W    -j- 

Rhamnonic  acid,  C6H12O6;  lactone W 

Xylonic  acid,  C5H10O6 first— ,  then    + 

Strontium  salt ]\' 

Lyxonic  acid,  C5H10O6 W   -f 

Sbccharinic  acid,  C6H,,O6;  lactone  (saccharin ) W 

Sodium  and  calcium  salts W 

Isosaccharinic  acid,  C6H,2O6;  lactone  (isosaccharin) W    + 

Sodium  salt 

Anilide r 

Metasaccharinic  acid,  C6H12O6,  lactone  (metasaccharin)  W 

Quinic  acid,  C7H,2O6  (cyclic) W          —  r 

Chitaric  acid,  C6H,0O6 ?     -f 

15.  Acids  with  Seven  Atoms  of  Oxygen  and  Derivatives. 
[For  aldehydes  see  under  oxyaldehydes  (sugars).] 

Trioxyglutaric      acid      (from     arabinose)      (COOH)2. 

(CHOH)3 W 

Potassium  salt // 

Saccharonic    acid,     (COOH)(OH)(H)C— C(H)(OH)— 

C(CH3)(OH)(COOH);  lactone W 

rf-Gluconic  acid,  C6H12O7,  calcium  salt,  lactone W 

/-Gluconic  acid,  C8HI2O7,  calcium  salt.  W 

j-Gluconic  acid,  C6H12O7 W  r 

Glucoronic  acid,  C6H,,,(  >7 iy    \ 


ACTIVE    ORGANIC    COMPOUNDS 


Derivatives:  Thymol-  and  dichlorthymolglucoronic 

acid ? 

rf-Gulonic  acid,  C<5H12O7;  lactone li' 

/-Gulonic  acid,  C6H12O7 ;  lactone W 

Phenylhydrazide W    -+- 

z-Gulonic  acid,  C6H12O7 W  * 

</-Mannonic  acid,  CgH^C^;  lactone W 

/-Mannonic  acid,  C6H12O7;  lactone W 

z-Mannonic  acid W  r 

d-ldonic    acid,    C6H12O7;     cadmium    salt    -f-    cadmium 

bromide • W    -\- 

/-Idonic    acid,    C6H12O7  ;     cadmium    salt    -f-    cadmium 

bromide W 

^-Galactonic  acid,  C6H12O7;  lactone W 

Derivative:  Calcium  salt.  W    — 

/-Galactonic  acid,  C6H12O7;  lactone W    -f 

i-Galactonic  acid,  C6H12O7 W  r 

Talonic  acid,  C6H12OT W 

a-Rhamnohexonic  acid,  CTHUO7;  lactone W 

/3-Rhamnohexonic  acid,  C-HUO7 ;  lactone W    + 

Chitaminic  acid,  C6Hn(NH2)O6 ? 

Oxygluconic  acid,  C6H10O7  —  2H2O W 

16.  Acids  with  Eight  Atoms  of  Oxygen  and  Derivatives. 

Dibasic  acids  ( tetroxyadipic  acids). 
flf-Saccharic  acid,   C6H10O8  ;  lactone,  ammonium-, potass. 

salt W    -f- 

/-Saccharic  acid,  C6H10O8;  potassium  salt W 

z-Saccharic  acid,  C6H10O8 W 

Isosaccharic  acid,  C6H10O8;  diethyl  ester,  diamide W    -|- 

oMVlannosaccharic  acid,  C6H10O8;  lactone,  C6H6O6 II' 

/-Mannosaccharic  acid,  C6H10O8;  lactone W 

z'-Mannosaccharic  acid,  C6H10O8 W  r 

aMdosaccharic  acid,  C6H10O8 W 

/-Idosaccharic  acid,  C6H10O8 W 

Mucic  acid,  C6H10O8 W 

Allomucic  acid,   C6H10O,, W 

^/-Talomucic  acid,  C6H10O8 W    + 

/-Talomucic  acid,  C6H10O8 W 

Monobasic  acids  (heptonic  acids). 

a-Glucob.eptonic  acid,  C-HUO8;  lactone W 

/3-Glucoheptonic  acid,  C7HUO8;  lactone W 

^-Galactosecarboxylic  acid,  C7HUO8;  barium  salt W    -f 

^/-Fructosecarboxylic  acid,  C7HUO8;  lactone W    -(- 

i/-Mannoheptonic  acid,  C7HUO8  and  lactone W 


26 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


/-Mannoheptonic  acid,  C7HMO8;  lactone W    -\- 

<-Mannoheptonic  acid,  C7HUO8 W  r 

Rhamnoheptonic  acid,  C8H16O8;  lactone W 

17.  Acids  with  More  Than  Eight  Oxygen  Atoms  and 
Derivatives. 

Dibasic  acids. 

0-Glucopentoxypimelic  acid,  C7H12O9;  lactone  acid W    -f 

a-Glucopentoxypimelic  acid,  C-H^Os, W  t 

Monobasic  acids. 

a-Glucooctonic  acid,  C8H16O9;  lactone W    -f 

/S-Glucooctonic  acid,  C8H16O9;   lactone W    -(- 

Rhamnooctonic  acid,  C8H16O9;  lactone W 

^-Mannooctonic  acid,  C8Hj6O9;  lactone W 

o-Gluconononic  acid,  (^H^OK,;  mixed  with  lactone W    -(- 

rf-Mannonononic  acid,  C^HjgOio;  lactone 

18.  Oxyaldehydes,  Aldoses,  Aldehyde  Sugars. 

(a)  Pentoses: 

/-Arabinose,  C5H10O5 

Derivatives:     Osone,    tetracetate     (A),     diacetone, 
benzylarabinoside  ( W), 

/3-Arabinochloral,  C7H6C13O5 W 

Phenylosazone  (A} beginning    -f    then   t 

(/-Arabinose,  C5H10O5 

i-Arabinose,  C5H,0O5 r 

Rhamnose,   C6H12O5 w 

A 
Derivatives:  Phenylhydrazone,  oxime W    -f- 

Ethyl-,  methylrhamnoside A 

Fucose,  C6H12O5 #/ 

Xylose,  C5H1005 w 

Derivatives:  o-Methylxyloside.  W    -f 

0-Methylxyloside,  xylochloral,  osazone  A 
Lyxose,  C5Hi0O5 «/ 

(6)  ff ex oses\ 

^/-Glucose,  C6H1206 A ,  W 

Derivatives  :  a-Methyl-  and  a-ethylglucoside  (  W},    ' 
Chloralose     [CsHnClsO6]    (A,    alka- 
lies),    acetochlorhydrose      [C6H7OC1 
(C2H8O2)4],    octoacetate,    (B}t    pent- 
acetate    (C),    glucoseammonia     (W) 


ACTIVE    ORGANIC    COMPOUNDS 


Mercaptal  (  Wj,  diacetone,  phenyl- 
hydrazone  (  W),  osazone  (Aa),  osone 
(  W7),  oxime  ( W7),  dextroseamido- 
guanidine  hydrochloride  (  W),  anilide 
and  toluidide  (A),  anhydroglucose- 

levoglucosan J 

/-Glucose,    C6H12O6 W 

Derivatives:  a-Methylglucoside W 

Osazone Aa 

t-Glucose,  C6H12O6 W  r 

Glucosamine,  C6HUO5NH2, salts,  W    + 

Isoglucosamine,  C6HnO5NH2 salts,  W 

rf-Gulose,  C6H1206 W 

/-Gulose,  C6H12O6    sirup,  W    + 

j-Gulose,  C6H12O6 W 

rf-Mannose,  C6H12O6 W 

Derivatives  :  Oxime W    + 

Phenylhydrazone    (W  —  HC1),    osa- 
zone   (Aa ) 

/-Mannose,  C6H12O6 sirup  W 

Derivatives:  Phenylhydrazone  ( W  -f  HC1),  osa- 
zone   (Aa)  -f- 

j-Mannose,  C6H12O6 W  >' 

rf-Galactose,  C6H12O6 W    + 

Derivatives:  Oxime  (  W),  a-methylgalactoside  (  W}, 
0-methylgalactoside  ( W  -f  borax) 
ethylgalactoside  (  W),  pentacetate  (C) 

Anilide,     toluidide,     phenylhydrazone  A 

Mercaptal W 

Osazone 

/-Galactose,  C6H12O6 W 

Derivatives :  Phenylhydrazone W    -j- 

Osazone ? 

i-Galactose,  C6H12O6 W  r 

Talose,  C6H12O6 W    +         r 

Sorbose,  C6H12O6 W 

Derivative:   Methylsorboside W 

Idose,  C6H1206 W  +?  +?  r 

Rhamnohexose,  C7HUO6 W 

c)  Heptoses: 

a-Glucoheptose,  C7HUO7 W 

Mannoheptose,  C7H14O7 W    T    —  r 

Rhamnoheptose,  C8H16O7 W    + 

d)  Octoses : 

a-Glucooctose,  C8H16O8 W 

rf-Mannooctose,  C8H16O8 sirup  W    + 


28 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


e)  Nonoses: 
Glucononose,  QH^O,,  ...........................  sirup  W 

Mannononose,  QH^O.,  ...............................    W 


19.  Oxykctones,  Ketoses,  Ketone  Sugars. 

rf-  Fructose,  levulose,  C6H12O6  .............    ...........    W 

Derivatives:    Oxime,    anilide    (A),   osazone    (Aa} 

pentacetate  .......................    C 

/-Fructose,  C6H12O6  .....................  ..............    W 

Derivative:  Osazone  .............................  Aa 

/-Fructose,  a-acrose,  C6H12O6  .......................... 

Invert  sugar  —  {/-glucose  (dextrose)  —  ^/-fructose  (levu- 
lose) .............................................    W 


• 


20.  Disaccharides,  C12H22On. 

Cane  sugar W 

Milk  sugar  (  -f  H2O) W 

Maltose  (+  H2O) W 

Isomaltose W 

Trehalose  (my cose)     (  -j-  2 

H20) W 

Melebiose Ur 

Turanose II' 

Lupeose W 

Cyclamose W 

Agavose // ' 

21.  Trisaccharides,  C18HS2O16. 
Meletriose,    raffinose  (  -f  5 

H20) W 

Melezitose  (  +  2H2O) W 

22.  Polysaccharides. 

Gentianose,  C36Hfl2O3l  ? W 

Lactosin,  C36H62O31  ? W 

Stachyose,  ? W 

23.  Carbohydrates,  (C6H10O5)fl. 
Amorphous  soluble  starch  .  W 
Crystallized  soluble  starch, 

amyloilextrine W 

Achrodextrine [V 

Maltodextrine W 

Wood  dextrine W 

Fermentation  gum,  dextrane  W 

y-Galactan // 

a-Galactan W 

Glycogen II' 

Fermentation  mucin W 

Cellulosin W 


• 
i 

i 


Cellulose  (CuO-ammonia,  HC1) 

a  and  ft  Amylan W 

Gelose W  +  acids 

Graminin W 

Inulin W 

Irisin W 

L/evosin W 

Levosan W 

Sinistrin W 

Triticin W 

Levulin  (synanthrose) W 

24.  Gums. 

Arabin,  arabic  acid W 

Wood  gum,  xylan  W 

Vegetable  mucilage W 

Wine  gum W 

25.  Pectin  Bodies  W,  -{-,—,  *'. 

26.  Alcohols  and  Acids  of  Un- 

known Structure. 

Quebrachol,  C20H34O   C 

Cupreol,           "  "    "   A 

Cinchol,           •«  «•  «  c 

Cholestol,  C22HS80 A 

Cholesterin ,  C26H44O A 

Phytocholesterin,  C26H44O  .  A 

Isocholesterin,         "   "   "    .  E 

Paracholesterin,      «««««,  c 

Caulosterin,              •««««*.  £• 
Quinovic     acid,     C3!,H48O6, 

K-salt W 

Quinaethonic  acid,  C14H,8O9  W 
Atractylic  acid,  Cjo^SjO^, 

K-salt W 


ACTIVE   ORGANIC    COMPOUNDS 


27.    Terpenes,  CJOH16. 

1.  Pinene  (Australene  4-,  Terebenthene  —  )•  •    / 

Hydrochloride,  C10H]6HC1 A 

Hydrobromide,  C10H16HBr '  A 

rf-Dibromide,  Ci0H16Br2 / 

rf-Nitrcscchloride,  CKH16NCC1 C 

/-Aldehyde,  C10H14O / 

2.  Caniphene A 

/-Hydrochloride,  C10H16HC1 A 

a-  and  £-Camphene  phosphonic  acids,  C10H15 

H2Po3----- A 

3.  Fenchene f 

4.  Limonene f       -f- 

Hydrochloride,  C10H16HC1 / 

Tetrabromide,  C10H16Br4 C 

a-Xitrosochloride,  C10H16NOC1 C    d  (  +  )   I  (  — ) 

.  .  ,    /  (-) 
a-Benzoyl  nitrosochloride, 

C]0H16NOC1.  C7H5O acetic  ether          d  ( — ) 

</-/3-Benzoyl  nitrosochloride, 

C10H16NOC1.C7H5O   acetic  ether          d  (  — ) 

a-Xitrolpiperidine,  C10H16XO.XC5H10 C     a(-f-) 

/3-Xitrolpiperidine,  C10H16NO.XC5H10 C     I   (-J-)    d  (  — ) 

a-Nitrolanilide,  C10H16.XO.NH.C6H5 C    </f-nl/(- 

/3-Xitrolanilide,      C10H16.XO.XH.C6H5 C    I 

Xitroso-a-nitrolanilide,  C10H16XO.X(XO)C6H5  C    d  (+)   I  (  — ) 
Xitroso-/3-nitrolanilide,  C10H16XO.X(XO)C6H,  C    I   (  — ) 
a-Xitrolbenzylamine,  C10H16XO.XHC7H7    ...    C    rf  (  +  )    /   (— ) 
«<  "  "       hydrochloride  and  nitrate      rf( — )   ^  (-f) 

rf-Limonene-a-nitrolbenzylamine-rf-tartrate . . 

' W+A 

/.  "         «         "  "          /  W+^4 

rf.         "        "        "  "          /  W-A 

d  W+A 


4- 


from  a-  and  /3-nitrosochloride  A 

Benzoylcarv-oxime,  C]0H14XO.COC6H5 C 

5.  Syli'estrene f 

Dihydrochloride,     hydrobrcmide,     tetrabro- 

mide,  nitrolbenzylamine C 

6.  Phellandrene /   d  (— ) 

Nitrite,  C10H16N2O3 C 

7.  Isoterpene f 

8.  Terpenene f 

1  Dipentene. 


-)  (r] 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


9.    Terpinolene  and  tetrabromide f 

Cadinene,     C15H24    (and    hydrochloride,    bro- 
mide, iodide) C 

Patchouline,  Ci5H,4 B 

a-  and  /3-Amyrilene,  C^H^ B        -f 

Tetraterebenthene,  C40H64 / 

Menthene,  C10H18 /       + 

Menthonaphthene,  C^H^ / 

28.  Camphors  and  Derivatives. 

Menthol,  C10H19OH A        -f 

Menthylamine,  C10H19NH, 

hydrochloride,    bromide, 

iodide W  </(  +  )  /(-) 

Formyl,  acetyl,  propionyl,  butyryl  menthyl- 

amine .' C   d  (  +  )   /  (— ) 

/-Menthylesters    of    benzoic,    succinic    and 

phthalic  acids B  I  (— ) 

/-Menthylcarbonate,  ( C10H19),,CO3 B  I  (  — ) 

/-Menthylurethane,C10H19O.CO.NH2 C  I  (— ) 

Menthonc,  C10H18O * /</(  +  )   /  (— ) 

Menthoneoxime,  Ci0Hi8.NOHand  hydro- 
chloride A    rf(+)   /  (— ) 

Iso-/-menthoneoxime,  Ci0H18NOH . . .   A  /  f \ 

Menthonitrile,  C9H17CX(/) A  / 

Terpine,  C,0H11S(OH)2  and  hydrate  (  -f  H2O).    / 

Terpineol,  C10H17(OH) /       + 

Cineol  (eucalyptol,  cajeputol ) ,  C10H18O / 

*-Borneol    (a-camphol),    C10H17OH,     Borneo- 
camphor  -f-,  valerian  camphor— A        -f- 

Ethylborneol,  C10H17OC2H5 /  rf  (+  ) 

Bornylchloride,  Ci0H17Cl,  bornylamine, 

C10H17NH2 .' A 

Bornyl  acetate,benzoate,  neutral  and  acid  suc- 
cinate,  neutral  and  acid  phthalate,  carbon- 

at* A  -     r 

Bornyl  phenylurethane (toluene)          d  (-f- )  /  (— )    r 

Chloral  bornylate(C10H170)(H)C(OH)(CCls)  \  R    .  .  ,  .    .     _ 

Bromal  bornylate /  ^~}       ^     }   r 

0-Borneol  ( /3-camphol ) ,  isocamphol,  from  d-  and 

/-camphor A    d  (— )    /  (— ) 

Pinol,  sobrerone,  C10H16O f 

Pinol  hydrate,  sobrerol,  C10H16O.H.OH A    d  (  +  )   /  (— )    r 

Caw/Aor,C10H,8O,  laurel  camphor  -f-,  matrica- 

ria  camphor-, A    d  (+)   I  (— )   r 


ACTIVE   ORGANIC    COMPOUNDS 


Derivatives  from  d-  and  l-camphor  : 

PflrrrnVjorovimp    O    T~T    T^OH   .                             .    A 

I   (4-) 

d  (     \ 

Camphoroxime  hydrochloride,  C10H16NOH. 
HCl      •  •  •  •    A 

I  C+) 

u  \     ) 

d  (—\ 

a-Camphor  sulphochloride,  C10H15OSO2C1.  .  .    C 
Benzalcamphor,    C10HUO.C7H6;    benzylcam- 

•nhnr    P    "FT    O  P  TT                                                              A 

rf(-f) 

d  (  +  ) 

I  (-) 
/   (     \ 

Derivatives  of  d-camphor: 

*    \     ) 

Salts  W  A 

+ 

+ 

•  ««                      "                                                ,    R 

o          «             «                    <«           «                   ,  A 

4- 

a-Nitrosocamphor,  C10H15O.NO  B 
a-  and  0-Mono-  and  dichlorcamphor,  trichlor- 

+ 

-f 

+ 

r 

o-   and  £-Chlorbromcamphor,     C10H14ClBrO, 

Tnrl  panrnVior    O    "FT    TO                                                     C 

+ 

Camphor  sulphonic  acid,  C10H15O.HSO3  W 
Camphor'  sulphonamide,  C10H15O.SO2.NH2.  .     C 
a-Chlorcamphor  sulphonic  acid,   C10HUC1O. 

+ 

4_ 

i 

Salts  W 

+ 

a-Chlorcamphor      sulphon  chloride,       C10HU 
Pin  ^o  n                                                 .  .  C"  A 

a-Chlorcamphor    sulphonamide,    C10HUC1O. 

+ 

a-  and  /3-Bromcamphor  sulphonic    acid    and 

+ 

a-Bromcamphor  sulphonchloride  and  amide  C,  A 
Cyancamphor,  C10H15OCN,  cyanmethyl,  ethyl, 

+ 

4~ 

Methyl  camphor,  C10H15.OCH3  and  ethyl  cam- 

+ 

Compounds  of  camphor  with  chloral,  chloral- 

+ 

Compounds  of  camphor  with  phenol,  a-  and  /3- 

+ 

Camphinic  acid,    C10H16O2,  campholic    acid, 

+ 

Oxycamphocarbaminic    acid,     C10H16O.NH2. 

+ 

Methyl     hydroxycamphocarboxylic        acid, 
C.-H..O-.CH..COOH..                                         .    A 

+ 

CLASSIFICATION   OF   ACTIVE    SUBSTANCES 


Camphoric  acids,  C10Hi6O4,  d  from  laurel  cam- 
phor, /  from  matricario  camphor A 

Derivatives  of  d-camphoric  acid: 

Camphoric  acid  salts  (  W) ,  esters  (  f  ) 

Camphoryl  chloride,  Ci0H14O2Cl2 / 

diamide,  imide C 

Camphoryl  anhydride,  C10HUO3 B,  C 

Isocamphoric  acid,  C10H16O4 A 

Esters  of  the  /-acid / 

Isocamphoric  acid,  anhydride B 

Camphocarboxylic   acid,    C10Hi5O.COOH   = 

CnH1603 A 

Camphocarboxylic   acid  esters  and  methyl- 

camphocarboxylic  acid  esters f 

Oxy Camphocarboxylic  acid,    C,,H18O4>    and 

esters A 

Cyancampholic  acid,  C10H17O2.CN,  and  oxy- 

camphocarbaminic  acid A 

Camphoronic  acid,  C9HUO6 W 

Fenchone,  C10H16  O A 

Fenchyl  alcohol  (fenchol),  C10H17OH A 

Fenchone  oxime,.  C10H16.NOH.  A 

Derivatives  of  fenchone  oxime: 

Fenchone  nitrile,  C10H15N A 

Fenchylamine,  C10H17NH2 A 

Benzylidene  fenchylamine A 

Formyl,    acetyl,    propionyl,   butyryl  fen- 
chylamine       C 

o-  and    />-Oxy-  and    methoxybenzylidene 

fenchylamine C 

Pulegone,  C10Hi6O / 

Pulegone  hydrobromide,  Ci0H16O.HBr A 

Pulegone  oxime,  v  C10Hi6NOH,    and   hydro- 
chloride  A 

Thujone,  Tanacetone,  C10H,6O / 

Carvol,  C,0HUO / 

Hydrogen  sulphide  carvol,  C,0HUO.H2S C 

Dihydrocarveol,  C,0Hj8O '/ 

Dihydrocarvone,    Ci0H18O,  /,   and  dihydro- 

carvoxime,  C10H,6NOH (?) 

Eucarvol,  Ci0H14O / 

1  Carvacrol. 


</(+) 

'  (-) 

r 

I  (+) 

rf(-) 

<<+> 

/  (-) 

rf(-h) 

*(+) 

'  (+) 
<*(+) 

i  (-) 

/  (-) 

r 

r 

^(•f) 

/  (+) 

{(-) 

,,+, 

d(-) 

+ 
*(+) 

i  (-) 

l.CH 

rf(-) 

r 

I? 


ACTIVE    ORGANIC   COMPOUNDS 


33 


_  2 


Aliphatic  Camphors  and  Terpenes. 
Licareol   (Aurantiol,    lavendol,    nerolol,  lina- 
lool),     C10H180,     [(CH2  =  C.CH3-CH2- 

CH  =  CH)(H)C(CH3)(CH2.CH2.OH)]. ..  j 

Coriandrol  ( d  licareol )  C10H18O /        -f 

Rhodinol  (citronellol )  C10H18O /       -j-1 

OYm/,C10H160 / 

lonone,  C13H20O / 

Irone,  C13H20O /        + 

Citronellal,  C10H18O /        + 

29.  Ethereal  Oils.     Essential  Oils. 

+  —  -r  and  — 


Angelica                 Oil 

Asafoetida               Oil 

Andropogon          Oil 

Basil 

Carrot 

Cajeput                     " 

Bergamot 

Copaiba                     '  ' 

Cedarwood               " 

Betel 

Cubeb 

Eucalyptus 

Calamus 

Curled  mint 

Fir  needle 

Caraway 

Elemi 

Sandal  wood             " 

Cardamom                 " 

Frankincense 

Turpentine               " 

Cascarilla 

Geranium                 " 

Celery 

Ginger                      " 

Chamomile 

Gurjun  balsam        " 

. 

Chekenleaf               " 

Hemlock 

Coriander 

Hemp 

Costus 

Juniper 

Dill 

Kneepine 

Fennel 

Lavender                  '  ' 

Lemon                       '  ' 

Onion 

Lime 

Parsley 

Mace 

Rose 

Marjoram                  " 

Rue                            " 

Mandarin 

Silver  fir 

Mastic 

Storax 

Muscat 

Tansy 

Myrtle 

Thuja                        " 

Orange                       " 

Thyme                       " 

Orange  blossom       " 

Wormseed 

Para-coto  bark         " 

Ylang-ylang 

Pine  needle              " 

Poley 

Savin 

Sassafras 

Spike 

Star  anise                  " 

1  From  licareol  acetate, 

mellisa  oil  or  citronella  oil. 

From  rose  oil. 

3  Geraniol. 

34 


CLASSIFICATION   OF   ACTIVE    SUBSTANCES 


30.  Resin  Acids. 

+ 

+ 
+ 

+ 
+ 

_L 

-f 
+ 
T 
+ 

+ 

+ 

+ 
+ 
_l_ 

rf:(-f) 
rf(  +  ) 
rf(+) 

d(-) 
<*(-) 

rf(-f) 

+ 

/  (-) 
I  (-) 

'  (~) 

I  (-) 
/  (  \ 

r 
r 

r 

r 
r 
r 
r 

r 

i 

i 

i 

i 

Svlvir  arid    C    H    O    .                                                   •    A 

T?1*»mi  flpiH     OHO                                                                >    A 

31.  Aromatic  Amines. 

Diphenylethylenediainine       (NH2)(C6H5)(H) 

CPi'WUPTIVNHI                                                •     E 

a-Tetrahydronaphthylamine   hydrochloride-  •  .   W 
1-5  —  Tetrahydronaphthylenediamine       hydro- 
chloride       w 

32.  Alkaloids. 
a.  Alkaloids,  of  which  Several  Optical  Modifica- 
tions are  Known,  and  Related  Bodies. 
a-Methylpiperidine  (a-pipecoline),  CSHIONCHS    / 
/3-Methylpiperidine  (£-pipecoline),  C5H10NCH,    / 

a   Fthv1r»ir»*»riHin*»     P  H     VP  TT                                                 f 

o-Propylpiperidine,       a-conine,       C5H10NC3H7 

Conhydrine  (conydrine)  and  pseudoconhy- 
drine   C  H   NO  f 

Coniceine,   C8H,5N(a-  P-  and   y  forms     in- 

Paraconine,  C8H,7N  (isopropylpiperidine)  -    / 
a-Isobutyl-piperidine   C  H   XC  H  f 

Eccronine     C  H    XO     livdrorliloridp                      •    US 

Cinnamyl-ecgonine     methyl     ester    (C.^H;. 
C  H    (  )  C'  H     \T()   \      hvflrnrhlorirlp                          US 

Benzoyl-ecgonine   methyl   ester   (cocaine), 
C.w.NO,  .                                                          r 

Anhydro-ecgonine,  C9H,3NO2  from  f  and  — 

Ecgoninic  acid.  C:H,,N():,,  from    •    and  — 

Tropinic   acid,    CHH,SNO4,  from         and 

\*  \  ) 
I  (4-) 

Atropine,  C,7H2SNO:,  A 
Hvoscvamine.  C..H...NO.  .                                       ,    A 

ACTIVE    ORGANIC    COMPOUNDS 


35 


Pseudohyoscyamine,  C,7H23NO3  ..............    A 

Hyoscine,  C17H,1NO4  ........................    A 

Tropine,  C8H15XO3  ..........................    A 

b.  Alkaloids,  of  which  Only  One  Optical  Modification  is  Known. 
Nicotine,  C10HUN,  ..........................     / 

Salts  ...................................    /r         + 

Solid  Alkaloids. 

The  direction  of  rotation  is  given  for  the  free  bases,  dissolved  in 
alcohol  or  chloroform,  and  for  the  salts  dissolved  in  water.  Alkaloids 
which  have  been  found  to  be  inactive  are  also  included. 

Alkaloids  of  Cinchona  Bark. 


*      * 


Paricine,   C16H1SX2O  ........ 

Cinchotenine,          C^H^X^ 
Cinchotenicine, 
Cinchotenidine, 
Cinchonine,  C19H,,X,O 

/3-and  S-Cinchonine,      '' 

Benzoylcinchonine,    ll 
a-Isocinchonine,  1  ,, 

Cinchoniline,    * 
£-Isocinchoirine,  ) 

Cinchonigine,  / 
Apocinchonine  , 
Diapociuchonine, 
Isoapocinchonine, 
Apoisocinchonine, 
Homocinchonine, 
Pseudocinchonine, 
Cinchonifine, 
Cinchonicine, 
Dicinchonine, 
Cinchonidine  " 

£-and7-Cinchonidine,   " 
Apocinchonidine,  " 

Homocinchonidine,        " 
Apoquinamine, 
Cincholeuponic  acid, 


a-  and  /3-Oxycinchonine,  .... 

.......  •  .....  C19H2aX302 

Apoquinidine, 
Apoquinine, 


4- 


- 


- 


Cupreine,               C19H,,X,O, 
Chitenine,  Ci9H2,X,)O4 

Cinchonamine,      Ci9H24N2O 
Cinchotine,  " 

Hydrocinchonidine,      " 

Quinamine,    C19H24X2O2 
Conquinamine,     " 
Quinamicine,        " 
Quinamidine,        " 
Geissospermine,   " 

Quinidine,   C20H.,4X2O2 

Quinicine, 

Quinine, 

Acetyl-  and  propionylquinine 
Xitrocamphorquinine  •  • 

Hy  droconquinine,  C20H26X2O2 

Hydroquinicine, 

Hydroquinine, 

Chairamine,          C.,,H.^2Ot 
Conchairamine, 
Chairamidine, 
Conchairamidine,         " 

Cusconine,  C23H,6X,O4 

Concusconine, 

Aricine, 


- 


CLASSIFICATION   OF   ACTIVE   SUBSTANCES 


.-llkaloids  of  Opium. 


Morphine,  C17H19NO3 
Codeine,  C,8H21NO3 
Methocodeine,  Ci9H23NOs . 
Pseudomorphine,  C^HggN 
Thebaine,  C,9H,,XO3 
Narcotine, 


Laudanosine,  C21H27NO4  •  •  • 

Laudanine,  C20H25XO4 

Cryptopine,  C21H23XO5 

Papaverine,  C20H21XO4 

Narceine,  C23H27NO8 

Pseudonarceine,  C23H27XO8 


Alkaloids  of  Strychnos  Species. 


Strychnine,  C21H    N  <  > 
Chlorstrychnine, 
C21H21C1N202 


Brucine,  C23H26X2O4 


Other  Alkaloids. 


Aconine, 

Aconitine,  C^H^XO^ 

Isoaconitine,  napelline, 


Lycaconitine,    C27H34N2O6.  •• 
Arginine,  C6H14X4O2  ........ 

Bulbocapnine,  C84HMN2O7  (?) 
Corydaline,  C22H27XO4  ...... 

Oxyacanthine,  CWH,9XO:J  •  •  • 
Pelletierine,  ChH,3XO  ....... 

Pilocarpine,  C23H:UX4O4  ..... 

Quebrachine,  C21H2fiN2O:,  .... 

Hyoscyamine,  C,7H23NOS  ---- 

Pseudohyoscyaniine, 

CI7H23N03  .............. 

Hyoscine,  C17H2,NO4  ....... 

Aspidospermine,  CT2H^.2O2  • 
Aspidosperm  atine, 

Cr2H28N202  ............. 

Colchicine,  CMH25NOH  ...... 


- 


Echitamine  (Ditaine), 

C22H28N204    

Hydrastine,  C21H21NO6-.- 
Imperialine,  C85H80NO4C?). 
Hydronicotine,  C10H16N2  • . 

Paytine,  C21H24N2O 

Sparteine,  C15H26N2 

Aribine,  C23H20N4 

Berberine,  C20H17NO4 

Chelerythrine,   C,7H13NO4 

Cevadine,  CS2H49NO9 

Delphinine,  CJ2H.}5NO6.  •  • 
Delphinoidine,  Ci-jH^N-jO- 
Hydrastinine,  CUHUNO2  . . 
Methylhydrastine, 


Piperine,  C17H19NO3 

Staphisagrine,  C,2H33NO5 
Cytisine  (Sophorine), 
CnH14N20 


33.  Gluco sides. 


Apiin,  C27H3201B    ...........  A 

o-  and  0-Chinovin, 

C»H4h08(?)  ............    ./ 

Coriamyrtin,  CsoH.^0,0  .....   A 

AmyKflalin,  C,0H,TX()n    ....    /r 

Coniferin,   C16H22OB 
Glycovanillin,C14H,.<  ). 
Convallamarin,  C,:II,,(  ),., 
Glucoside  from  iv    leaves, 


W 

It' 
.  / 


-:-.  Helicin,  C,:,H,,.O7   A 

Hesperidin,  C,,II,8O12   W 

Xaringin  (Aurantin), 


C21H2fiO, 


Phloridzin,  C,,H,,(  ),„    A 

Populin,  C,0H,,o.   W 

Salicin,  C1;(H,HO7     W 

Tetrabutyrylsaponin, 

c^ii^o.^c.iLo  4 w 

....  Aa 


Thevetin,  C54HH4()21    .... 

The  synthetic  glucosides  and  analogous  compounds  with  other  sugars 
are  given  under  the  latter  head. 


ACTIVE    ORGANIC    COMPOUNDS 


37 


34.   Bitter  Principles  (Santonin  Group],  Coloring-Matters 
and  Unclassified  Compounds. 

Santonin  Group. 


Santonin,  C15H18O3  ......  C,  A 

o-  and  £-Metasantonin, 

C13H18O3  ..............    A 

Santonide,  C^H^O^  ......  C,  A 


Parasantonide,  C15H18O3  ---- 
Metasantonide,  C15H18O3  .  . 
Santonousacid  (and  esters), 


Isosantonous  acid  (and  es- 
ters), C^H^O,,  .......    A 

Disantonous  acid 

(C15H1903)2  ...........    A 

Santoninic  acid  (and  salts) 

C15H2004  ..............    A 

Santonic  acid  (and  esters), 

C15H2004  ..............     C 

Santonyl  chloride, 

C13H190SC1  ............    C 


Santonyl  bromide, 

C13H1908Br C 

+       Santonyl  iodide,  C13H19O3I    C 
Parasantonic  acid  (and  es- 
ters). C15H2004 C 

Metasan tonic  acid, 

C13H2004 C 

-j-       Dehydrophotosantonic 

acid,  C13H20O4 A 

i        Photosan tonic  acid, 

C15H2205 A,  C 

—  r  a-Ethylphotosantonate  ...    A 
ft.      •"<          "         "  A 

Isophotosan tonic  acid, 

C15H2._A A 

Hydrosantonic  acid, 

C13H2204 A 


Echicerin,  C30H^O, C,  E 

Echitin,  C32H52O2 C,  E 

Echitein,  C42H70O2 C,  E 

Echiretin,  C35H^O2 E 

Euphorbon,  C15H24O C 

Lactucerin,  C,SH44O2  (?)...    E 
Lactucol,  C13H20O E 


Other  Bodies. 

I  Quassiin,  C32H42O10(?)- - 


!  Asebotoxin,  C31H31010(?)-      C 
W,  A 

Picro toxin,  C12HUO5 A 

Erythrocentaurin,  C27H24O8  A 

Ostruthin  ( C14H17O2)W   A 

Hematoxylin,  C16H14O6  •  •.   A 


35.  Bile  Acids. 

Cholanic  acid,  C20H28O6 A 

Cholalic  acid  (and  salts  and 

esters) ,  C24H40O5 A 

Desoxycholic  acid 

Isocholanic  acid,  C25H38O7 ...  A 

Dehydrocholic  acid,  C25H36O3  A 

Bilianic  acid,  C^H^Og A 

Glycocholic    acid,  C26H43NO6 

and  Na  salt A 


a-  and  /3-Hyoglycocholic  acid,       i 
C26H43NO5,  Na  salt A 

a- and  j9-Hyoglycocholic  acid, 
C26H43N05,  Na  salt W 

Taurocholic  acid, 

C,6H45NSO7  and  Na  salt.  W 
-J-     Lithobilic  acid,  CgoH^Oe  •  •  -   A 


38  CLASSIFICATION   OF   ACTIVE   SUBSTANCES 

36.  Proteid  Substances. 


Egg  albumin U'      -    Syntonin W -f  HC1 


Serum  albumin W 


Propeptone W 


Casein,   W(   --    HClorNaOH)  Protalbumose W 

Serum  globulin  .  • NaCl  sol  Deuteroalbumose W 


Lactalbumin W 

Glutin W 

Chondrin  //'  \   NaOH 

Hemielastin W 

Paralbumin //•'--  NaOH 

Mycoprotein W+  NaOH 


Heteroalbumose W+  NaCl 

Fibrin  peptone W 

Elastin  peptone H' 

Vegetable  peptone W 

Fibrinogen W+  NaCl 


37-  Derivatives  of  Asymmetric  Nitrogen. 
Methylethylpropylisobutylammonium  chloride,   N(CH3)(C2H5) 

(CSH7)(C4H9)C1....' '. W 

Compounds  of  the  chloride  with  PtCl4  and  AuCl:! W 

Acetic  acid  salt  of  the  base W 

Sulphuric  acid  salt  of  the  base // 

a-BenzylphenylallylmethyW-camphor  sulphonate,    C6H5.CH2.N 
(C6H5)(C8H5)CH8.S03C10H150 !...."...    }\' 

Iqdide,  C6H5.CH,-N(C6H5)(C3H5XCH3)I 

Bromide,  C6H5.CH2— N(C6H5)(C3H5)(CH3)Br A 


38.  Derivatives  of  Asymmetric  Sulphur. 


rf-Methylethylthetine  ^/-camphor  sulphonate W 

rf-Methylethylthetine  d-brom  camphor  sulphonate   H 

(/-Methylethylthetine  platinichloride W 


As  the  table  shows,  a  great  many  active  bodies  are  known, 
and  mainly  from  the  animal  or  vegetable  organism,  which 
have  been  found  only  in  the  one  form,  either  right  or  left 
rotating.  On  the  other  hand,  of  the  synthetically  prepared 
active  bodies,  the  constitution  of  which  has  been  established, 
the  greater  number  are  already  known  in  the  two  active  modi- 
fications, and  also  in  the  racemic  form.  An  enumeration  of 
the  substances  given  in  the  tables  shows  this  result  : 

Right  rotating  only 286  \ 

Left  rotating  only 237  I    625 

Right  and  left  rotating 102  > 

Kacemic  forms 73 

If  the  salts  and  c^tt-rs  of  the  active  acids   and   bases,  which 


NATURE  OF  THE  ROTATING  POWER  39 

were  not  included,  be  counted  in,  the  number  of  active  bodies 
known  at  the  present  time  [1898]  will  be  over  700.  At  the 
time  of  the  appearance  of  the  first  edition  of  this  book,  1879, 
the  number  was  about  300. l 

On  the  relation  of  crystalline  form  to  direction  of  rotation  of 
bodies  of  these  groups  consult  §  12. 


III.  NATURE  OF  THE  ROTATING  POWER 

9.  Distinction  between  Crystal  Rotation  and  Liquid  Rotation — 
Rotation  of  Vapors — Molecular  Rotation. — The  fact  that  bodies  of 
the  first  class  exhibit  rotating  power  in  the  crystalline  con- 
dition only,  and  lose  this  power  completely  when  brought  into 
solution,  shows  that  the  cause  of  the  rotation  must  depend  on 
the  crystalline  structure;  that  is,  on  a  definite  arrangement  of 
molecular  groups  (crystal  molecules) .  In  fusing  or  dissolving 
the  body,  this  is  destroyed,  and  the  optical  activity  disappears. 
The  phenomenon  is  here,  therefore,  a  purely  physical  one. 

Substances  of  the  second  and  third  classes,  on  the  contrary, 
rotate  in  the  liquid  condition.  It  is  probably  true  of  bodies  in 
this  condition  that  the  smallest  amount  of  substance  acting  as 
a  unit,  does  not  consist  in  single  chemical  molecules,  but  in 
molecular  aggregations.  There  are  grounds  for  believing  that, 
at  least  in  concentrated  solutions  of  a  solid  body  in  a  liquid, 
the  solid  is  not  completely  separated  into  single  molecules  or 
further  into  its  ions,  but  that  molecular  groups  or  aggregations 
exist.  If  then,  a  liquid  is  found  to  possess  rotating  power  it  is 
conceivable  that  the  origin  of  this,  as  in  the  case  of  crystals, 
should  be  found  in  a  definite  structure  of  these  molecular 
groups.  In  this  event,  the  phenomenon  would  fall  in  the  field 
of  physics. 

If  the  cause  just  suggested  is  sufficient,  it  follows  that  the 
rotating  power  of  an  active  substance  must  disappear  as  soon  as 
the  same  is  decomposed  into  single  molecules  ;  that  is,  as  soon 
as  it  is  brought  into  the  condition  of  a  true  vapor.  This  import- 
ant experiment  was  undertaken  first  by  Biot"  in  the  year  1817. 
He  allowed  turpentine  vapor  to  pass  through  a  metallic  tube 

1  Since  the  above  was  written  nearly  100  new  active  compounds,  mainly  esters 
and  complex  substitution  products,  have  been  added  to  the  list.    Tr.  (1900). 
-  Biot  :  Mem.  de  1'Acad.,  2,  114. 


40  NATURE  OF  THE  ROTATING  POWER 

30  meters  in  length,  and  closed  at  both  ends  with  glass  plates, 
and  observed  that  it  possessed  the  power  to  produce  rotation  in 
tne  polarized  ray.  Exact  measurements  could  not  be  made  as 
the  vapor  suddenly  became  inflamed  and  destroyed  the 
apparatus.  It  was  not  until  1864  that  the  experiment  was 
repeated,  and  by  Gernez,1  who,  by  the  aid  of  excellent  instru- 
ments, determined  the  rotation  of  a  number  of  active  liquids 
with  increasing  temperature  and  finally  in  the  state  of  vapor. 
The  substances  tested  were  sweet  orange  oil  (  +  ),  bitter 
orange  oil  (-(-),  turpentine  oil  (  —  ),  and  camphor  (-J-).  Iu 
all  cases  the  specific  rotation,  [<*]  (that  is  the  rotation  cal- 
culated for  unit  density  and  unit  length  of  active  layer), 
decreased  with  increase  of  temperature,  and  finally  when  the 
vapor  was  examined  it  was  found  that  the  specific  rotation  had 
decreased  to  an  extent,  corresponding  to  the  increase  in 
temperature.  In  illustration  of  this,  the  following  numbers 
obtained  from  oil  of  turpentine  and  camphor  are  given  : 


Density  Observed    Length  of  the 

State  of  aggregation.     Tempera  |    referred    to  angle    of  observation 

ture.               water.  rotation,     tubes  in  deci- 

d.  a.           meters.     /. 

Turpentine  oil  (left  rotating). 


LiQuid 

r  11°      0.8712 

J      rvS°             f\  Tnnfi 

15-97° 

T  A      A  n^ 

0.5018 

36.53 

V&oor 

]    9°           0.7990 

1    I,S4               0.7505 
168°           n  nninS? 

14.47 

13-50° 
c  -?fi 

0.50215 
0.50237 

36.04 
35-Si 

Observed  vapor  density  at 
Theoretical  vapor  density  . 

5-7° 
168°  ^4 
.   ..11=4 

40.61 
981. 
700. 

35-49 

Camphor  (right  rotating). 

Fused  ............     I     204°         0.812  31.46°  0.5509          70.33 

Vapor  ............          220°         0.003843         10.98°         40.63  70.31 

Observed  vapor  density  at  220°  =  5.369. 
Theoretical  vapor  density    ----  =  5.252. 

The  density  of  the  vapor  at  the  temperature  of  the  experi- 
ments, is,  as  is  readily  seen,  very  nearly  the  same  as  the  theo- 
retical density,  and  it  follows  from  this  that  single  molecules, 
mainly,  and  not  molecular  aggregations,  must  have  acted  on 
the  polarized  ray.2  As,  moreover,  the  specific  rotation 

1  Gernez:  Ann.  scient.  de  1'Ecole  norm,  sup.,  i,  i. 

*  Ph.  A.  Guye  and  P.  do  Amaral  have  recently  observed  (Arch,  sc  phys.  de 
Geneve  [3],  33,  409,  513;  Wied.  Beibl.  1895,  792,  894)  agreement  in  Die  specific  rotation 


OPTICAL    THEORY    OF    CIRCULAR    POLARIZATION  41 

remains  undiminished,  the  optical  activity  must  be  a  property 
inherent  in  the  molecule  and  must  have  its  origin  in  the  arrange- 
ment of  the  atoms  in  the  same.  The  phenomenon,  therefore, 
belongs  in  the  domain  of  chemistry. 

The  optical  activity  of  crystals  on  the  one  hand,  and  of 
liquids  on  the  other,  are,  accordingly,  two  quite  distinct 
phenomena,  and  to  indicate  that  the  latter  resides  in  the 
individual  molecule,  Biot  gave  to  it  the  name  molecular 
rotation. 

But  this  term  has  already  been  applied,  as  mentioned  in  §  3, 
to  the  product  of  the  specific  rotation  by  the  molecular  weight  ; 

M 
that  is,  the  quantity  [M]  =         -  [«]  .     To  avoid   confusion  it 

may  be  better  in  the  latter  case  to  use  with  the  term,  molecular 
rotation,  the  symbol  [M]  . 

10.  The  Optical  Theory  of  Circular  Polarization  in  Quartz  was  first 
enunciated  by  Fresnel.1  This  theory  assumes  that  parallel 
to  the  principal  axis  in  quartz  a  peculiar  kind  of  double 
refraction  takes  place,  and  of  such  a  character  that  a  linearly 
polarized  entering  ray  is  decomposed  into  two  rays  which 
move  forward  in  helical  paths,  one  being  inclined  toward  the 
left  and  the  other  toward  the  right.  On  leaving  the  crystal 
these  circularly  polarized  rays  unite  to  form  again  a  linearly 
polarized  ray,  but  if  they  had  moved  through  the  crystal 
medium  with  unequal  velocities,  it  would  follow  that  the  new 
plane  of  oscillation  would  be  different  from  that  of  the  enter- 
ing ray.  It  would  be  turned  in  the  clock-hand  direction,  that 
is,  to  the  right,  when  the  polarized  ray  deviated  in  the  same 
direction  moved  with  a  greater  velocity  than  the  other,  and 
vice  versa.  The  existence  of  these  two  rays  in  quartz  was  first 
shown  experimentally  by  Fresnel,  and  later  by  Stefan,2  and 
also  by  Dove,3  who  found  that  they  are  absorbed  by  colored 
quartz  (amethyst)  in  unequal  proportions.  The  theory  of 

of  a  number  of  amyl  derivatives  in  the  liquid  and  vapor  condition.  An  exception 
noted  that  valeraldehyde  as  vapor,  rotates  only  about  half  as  much  as  it  does  as  a 
liquid  may  be  accounted  for  by  the  chemical  change  or  racemization  which  takes 
place  by  change  of  temperature  in  this  substance. 

1  Fresnel  :  Ann.  chim.phys.   [i],  28,  147. 

-  Stefan  :  Pogg.  Ann.,  124,  623. 

3  Dove:  Pogg.  Ann.,  no,  284. 


42  NATURE  OF  THE  ROTATING  POWER 

circular  polarization  has  received  a  very  full  mathematical 
treatment  at  the  hands  of  many  physicists,  and  for  this 
reference  must  be  made  to  other  works.1 

In  regard  to  the  structure,  which  a  crystalline  medium  must 
have  in  order  that  it  may  effect  a  rotation  of  the  plane  of 
polarization,  the  theory  assumes  an  uneven  condensation  of 
the  ether  around  the  molecules  of  the  body,  and  to  such  an 
extent  that  this  can  not  be  considered  as  infinitesimally  small 
as  compared  with  the  wave  length  of  the  transmitted  light. 
This  naturally  depends  on  a  definite  molecular  structure  of  the 
substance.  The  connection  of  direction  of  rotation  in  active 
crystals  with  the  existence  of  right  or  left  hemihedral  planes 
has  led  to  the  hypothesis,  that  in  these  crystals  the  particles 
are  arranged  with  reference  to  each  other  in  the  form  of  a 
right-  or  left-handed  screw  (spiral  stair  form).  This  view 
expressed  by  Pasteur,2  Rammelsberg,3  and  others,  has  received 
a  great  degree  of  probability  through  an  experiment  first  tried 
by  Reusch,4  and  later  followed  up  by  Sohncke.5  If  a  number 
of  thin  plates  of  optically  biaxial  mica  (12  to  36)  are  so  placed, 
one  on  top  of  the  other,  that  the  principal  axis  of  each  one 
makes  always  the  same  angle  (45°,  60°,  90°  or  120°)  with 
the  preceding  one,  a  column  is  produced  which,  like  an  active 
crystal,  has  the  power  of  rotating  the  plane  of  transmitted 
polarized  light,  and  either  to  the  right  or  left  as  opposed  to  the 
direction  of  the  twist  in  the  column  of  plates.  The  optical 
behavior  of  such  mica  combinations6  has  been  thoroughly 
studied  by  Sohncke  who  found  that  by  sufficiently  diminishing 
the  thickness  of  the  mica  plates,  a  combination  is  secured, 
the  rotating  power  of  which  follows  exactly  the  laws  that  hold 
for  active  crystals  ;  that  is,  the  amount  of  rotation  is  pro- 
portional to  the  length  of  the  column,  and  nearly  proportional 
inversely  to  the  square  of  the  wave  length.7  Based  on  a  theory 
of  crystal  structure  developed  by  himself,  Sohncke  has  further 

1  See  Winkelmann:  "  Handbuch  d.  I'hysik.,"  Breslau,  1894,  Vol.  II,  part  i,  page 
784;  Ketteler  :  "Theoretische  Optik.,"  Braunschweig,  1885;  Verdet:  "kecons  d'Optique 
physique." 

Pasteur  :  Consult  §  12. 

kninmelsberg:  Her.  d.  chem.  Ges.,  a,  31. 

Reusch  :  Pogff.  Ann.,  138,628. 

Sohncke  :  Ibid..  Supplement,  8,  16. 

These  columns  may  be  obtained  from  Steeg  and  Renter  in  Homburg. 

L.  Sohncke  :  "  Theory  of  Crystal  Structure."     Leipzig,  1879. 


OPTICAL  CONSTITUTION  OF  ACTIVE  LIQUID  SUBSTANCES    43 


shown1  that  not  only  in  the  trapezohedral-tetartohedral  group 
of  the  hexagonal  system,  but  also  in  others  of  the  hexagonal 
and  of  the  tetragonal  and  regular  systems,  a  certain  spiral- 
stair  arrangement  of  the  crystal  particles  can  exist  which  is 
accompanied  by  rotation  of  the  plane  of  polarization  ( See  §  5  ) . 
By  means  of  mica  plates  of  different  thicknesses,  arranged  one 
upon  the  other  with  the  axes  inclined  at  different  angles,  it  is 
possible  to  imitate  the  right-  and  left-handed  forms  of  such 
active  structures.  A  conception  very  similar  to  that  of 
Sohncke,  as  to  the  cause  of  crystal  rotation  has  been  developed 
by  Mallard  ;~  Wyrouboff  also  assumes  the  building  up  of 
layers  of  biaxial  plates.3 

ii.  Optical  Constitution  of  Active  Liquid  Substances. — For  a  given 
thickness  of  layer,  active  liquids  possess  the  same  rotating 
power  in  all  directions  ;  they  exhibit,  therefore,  the  same 
behavior  observed  in  active  regular  crystals.  The  property 
of  circular  double  refraction  is  inherent  in  the  latter,  and  if 
the  analogy  with  active  liquids  is  complete,  the  same  property 
should  be  expected  in  these  also.  This  question  was  definitely 
decided,  after  Dove4  in  1860  had  made  some  unsuc- 
cessful experiments,  by  E.  v.  Fleischl5  in  1884,  and 
according  to  the  method  of  Fresnel,  wrho  determined 
the  double  refraction  of  quartz  in  the  direction  of  its 
principal  axis  by  the  aid  of  a  combination  of  right- 
and  left-rotating  quartz  prisms.6  The  apparatus 
used  by  v.  Fleischl  consisted  of  a  glass  trough  in  the 
shape  of  a  parallelopipedon,  543  mm.  long,  and  20 
mm.  wide,  open  above,  and  divided  by  means  of 
glass  plates  set  diagonally  into  20  hollow  prisms, 
with  refractive  angles  of  120°,  and  two  end  prisms 
with  angles  of  60°.  Fig.  3  gives  a  shortened  illus- 
tration of  the  arrangement.  The  22  compartments 
were  filled  alternately  with  right-  and  left-rotating 

1  Ztschr.  fur  Krystallog.,  19,  529  ;  13,  214  ;  14,  426. 

2  Trait6  de  Cristallog,  a,  313  (1884). 

:  Wyrouboff:  Ann.  chim.   phys.    [6],   8,   340;  Jour.   de.   Physik.  [2],  5,  258  (1886); 
Bull.  Soc.  Min.,  13,  215  (1890). 
4  Dove  :  Pogg.  Ann.,  no,  290. 

•"  E.  v.  Fleischl :  Wiener  Sitzungsber.,  90,  II,  478  (1884);  also  Wied.  Ann.,  24,  127. 
(>  See  the  text-books  of  physics. 


Fig-  3- 


44  NATURE  OF  THE  ROTATING  POWER 

substances,  which,  by  proper  dilution  had  been  brought  to  possess 
exactly  the  same  refractive  indices.  In  a  first  series  of  experi- 
ments, solutions  of  saccharose  and  levulose  were  used,  and  in  a 
second  series,  right  orange-peel  oil  and  left  turpentine  oil. 
When  now  a  ray  of  light  from  a  very  fine  opening  (pin-hole) 
was  passed  through  this  system  of  prisms  and  examined  by  a 
reading  telescope,  two  bright  spots  instead  of  one,  were  seen 
at  the  other  end.  If  now  the  decomposition  of  the  original 
light  (ordinary  or  plane  polarized)  had  followed  as  in  the 
Fresnel  experiment,  the  two  emerging  rays  must  be  found 
circularly  polarized,  and  in  opposite  directions.  It  was,  in 
fact,  shown  by  a  well  known  method,  employing  a  quarter  wave 
length  mica  plate  and  rotating  nicol,  that  the  two  rays  had 
been  transformed  into  two  linear  polarized  rays  with  planes  at 
right  angles  to  each  other.  In  two  positions  of  the  nicol,  90° 
apart,  first  one  and  then  the  other  of  the  bright  spots  dis- 
appeared. 

It  is  therefore  apparent,  through  these  experiments,  that  the 
optical  cause  of  activity,  that  is  to  say,  the  manner  of  the 
wave  motion  of  the  ether,  must  be  the  same  for  liquids  as  for 
isotropic  crystals.  In  all  directions  in  both  media,  two  waves 
are  propagated,  which  are  circularly  polarized  in  opposite 
directions,  and  which  move  forward  with  unequal  velocities. 
It  has  been  mentioned  that  in  such  crystals  this  peculiarity  is 
found,  that  they  possess  neither  a  plane  of  symmetry  nor  a 
center  of  symmetry,  and  further  that  they  are  found  in  enan- 
tiomorphic  forms  of  which  the  one  turns  the  plane  of  polari- 
zation to  the  right,  and  the  other  to  the  left.  The  same  is  to 
be  assumed  concerning  active  liquids,  and  as  here  the  seat  of 
the  activity  is  found  in  the  single  molecules,  it  follows  finally 
that  an  asymmetric  structure  must  be  assigned  to  the  latter 
themselves. 

Tliis  conception  had  been  already  reached  in  another  way, 
and  through  the  investigations  of  Pasteur  carried  out  in  1848, 
which  led  to  the  following  conclusions  : 

12.  Investigations  of  Pasteur.  Molecular  Asymmetry. — As  Biot 
and  Seebeck1  recognized  in  1815,  common  tartaric  acid  rotates 

1  Biot  and  Seebeck  :  Bull.  Soc.  Philom.,  1815,  190. 


INVESTIGATIONS   OF    PASTEUR 


45 


to  the  right,  and  in  1842  it  was  further  observed  by  Mitscher- 
lich1  that  racemic  acid,  isomeric  with  tartaric,  is  inactive.  Pas- 
teur found  next,  that  from  a  solution  of  racemic  acid,  rhom- 
bic-hemihedral  crystals  of  a  double  salt  having  the  composition, 
NH,NaC^H4O6.4H2O,  similar  to  the  tartrate,  could  be  obtained 
by  slow  concentration  at  a  low  temperature.  But  these 
crystals  are  not  all  identical  in  crystalline  form,  for  two 
different  structures  may  be  easily  recognized.  Often  the 
crystals  appear  developed  as  illustrated  in  Figs.  4  and  5,  and 
in  this  case  the  differences  may  be  easily  recognized  even  by 


q2 


ft 


Fig.  4. 


Fig.  5- 


one  not  specially  trained  in  crystallography.3  If  the  crystals 
are  so  placed  that  the  two  narrow  surfaces,  q  and  q2,  are 
turned  toward  the  observer,  it  will  be  seen  on  some  individuals 
that  the  small  surface,  o1,  is  to  the  right  of  q  and  q2  (Fig.  4), 
and  on  others,  it  will  appear  that  this  surface  is  to  the  left  of 
q  and  q2  (Fig.  5).  There  is  exhibited  here  as  in  the  case  of 
quartz,  the  phenomenon  of  enantiomorphism,  or  "non- 
superposable  hemihedry,"  as  it  was  called  by  Pasteur  ;  one 
crystal  figure  is  the  mirror  image  of  the  other,  and  cannot  be 
covered  by  it. 

When  Pasteur4  had  separated  these  two  kinds  of  crystals 

1  Mitscherlich  :  Monatsber.  der.  Berl.  Akad.,  1842. 

2  Pasteur:    Ann.  chim.  phys.    [3],   24,  442;  Compt.  rend.  26,  535;    27,  367,  401, 
(1848)  ;  29,  297  (1849)  ;  Ann.  chim.  phys.  [3]   28,  56  (1850)  ;  Compt.  rend.  31,  480  (1850)  ; 
33,  217,  549  (1851)  ;  Ann.  chim.  phys.  [3],  31,  67  (1851). 

a  Crystals  with  the  same  surfaces  may  appear  also  in  forms,  other  than  those 
shown  ;  in  such  a  case,  measurements  of  angles  are  necessary  to  distinguish  one  kind 
from  the  other. 

*  An  explanation  of  the  manner  in  which  he  was  led  to  his  discovery  is  given  by 
Pasteur  in  his  "  Recherches  sur  la  dissymelrie  moleculaire  des  produits  organiques 
naturels,"  Soc.  chim.  de  Paris.  Lecons  de  chimie  profess£es  in  1860.  Paris  1861.  See 
Alembic  Club  Reprint,  No.  14- 


46  NATURE  OF  THE  ROTATING  POWER 

mechanically,  he  found  that  those  with  the  surface,  ol,  to  the 
right  of  q  and  q2,  when  dissolved  in  water  and  examined  in  the 
polariscope,  exhibited  a  right-hand  rotation,  while  those  with 
o1  to  the  left  showed  a  left-hand  rotation.  From  the  two 
crystallographically  different  sodium-ammonium  salts  he 
obtained,  on  the  one  hand,  dextro-,  and  on  the  other,  levo- 
tartaric  acid,  and  by  mixing  equal  parts  of  these  in  aqueous 
solution  he  obtained  an  inactive  liquid  which,  on  evaporation, 
furnished  crystals  of  racemic  acid.  Analogous  relations  were 
later  found  among  many  other  active  carbon  compounds. 

In  this  way,  it  was  for  the  first  time  shown  that  an  active 
substance  may  exist  in  two  forms,  right  rotating  and  left 
rotating,  the  rotating  power  being  under  like  conditions  the 
same.  From  the  observations,  it  was  further  apparent  that 
the  opposite  asymmetric  characteristics  which  the  two  kinds  of 
crystals  of  sodium-ammonium  tartrate  possess  belong  to  their 
molecules  also,  inasmuch  as  after  solution  in  water  they  show 
right  and  left  rotation.  This  led  Pasteur  to  the  view  that 
the  invidual  molecules,  as  all  other  material  objects,  in  respect 
to  their  forms  and  repetition  of  identical  parts,  fall  naturally 
into  two  classes  :  i .  Those  which  are  superposable  on  their 
mirror  images  (as  a  straight-stair,  a  cube)  ;  2.  Those,  whose 
mirror  images  can  not  be  covered  by  the  originals  and  which 
may  appear  in  two  oppositely  constructed  (enantiomorphic) 
forms  (spiral-stair,  irregular  tetrahedron,  right  and  left  screw, 
right  and  left  hand ) .  Molecules  of  the  first  class  possess  a 
symmetrical  structure  ;  in  the  second  the  atoms  are 
asymmetrically  ordered,  and  these  should  show  optical 
activity.  In  relation  to  racemic  acid,  and  the  two  tartaric 
acids  Pasteur1  remarked :  ' '  Are  the  atoms  of  the  right  acid 
grouped  in  the  form  of  a  dextrogyrate  helix,  or  do  they  stand 
at  the  corners  of  an  irregular  tetrahedron,  or  are  they  found  ar- 
ranged in  some  other  asymmetric  form  ?  We  are  not  able  to  an- 
swer these  questions.  But  of  this  there  can  be  no  doubt:  That  an 
i  metric  arrangement  of  the  atoms  must  exist  in  such  a 
manner  as  would  furnish  a  non-superposable  image.  It  is  just 
•  •ertain  that  the  atoms  of  the  left  acid  are  arranged  in  a 
manner  exactly  the  reverse  of  those  in  the  right,  and  finally 

1  "  Recherches  §ur  la  dissymetrie  moleculaire,"  Alembic  Club  Reprint,  p.  24. 


THEORY    OF    VAX  'T    HOFF   AND    LE  BEL  47 

we  know  that   racemic   acid  results  from  the  combination  of 
these  two  inversely  asymmetric  atomic  groups." 

Through  these  considerations,  Pasteur  introduced  a  new 
conception,  that  of  molecular  asymmetry,  into  the  science. 
Before,  however,  this  could  bear  fruit,  a  much  wider  develop- 
ment of  organic  chemistry  was  necessary,  and  only  after  the 
constitutional  formulas  of  a  large  number  of  carbon  compounds 
had  been  determined,  was  it  found  possible  to  trace  a  con- 
nection between  the  atomic  structure  of  molecules  and  their 
optical  activity.1 

IV.  RELATIONS  BETWEEN  ROTATING  POWER  AND  CHEMICAL 
CONSTITUTION  OF  CARBON  COMPOUNDS 

13.  Van't  Hoff-LeBel  Theory. — One  of  the  most  important 
advances  in  our  knowledge  of  optical  rotation  was  made  in 
1874,  when  J.  H.  van 't  Hoff,"'  then  in  Utrecht,  and  a  few  weeks 
later  J.  A.  LeBel,3  in  Paris,  furnished  the  proof  that  optical 
activity  has  a  definite  connection  with  the  structure  of  carbon 
compounds.  The  fundamental  conception  founded  on  this 
notion,  to  which  van't  Hoff  was  led  through  the  assumption 
of  a  tetrahedral  arrangement  of  the  atoms,  Le  Bel,  on  the 

1  An  essentially  different  hypothesis  to  account  for  the  activity  of  liquids  as  well 
as  crystals,  which  is  based  on  the  assumption  of  the  rotation  of  the  molecules,  has  been 
proposed  by  Fock  (Ber.  d.  chem.  Ges..  24,  101).  Wyrouboff  (Ann.  chim.  phys.  [7], 
i,  5  ;  Chem.  Centrbl.,  i,  260  (1894))  has  sought  to  show  that  the  rotation  of  crystalline 
organic  substances  in  solution  bears  relation  to  the  crystalline  structure,  and  is  not 
merely  dependent  on  the  nature  of  the  chemical  molecule. 

•  First  published  in  the  paper :  Voorstel  tot  uitbreiding  der  tegenwoordig  in  de 
scheikunde  gebruikte  structur-formules  in  de  ruirnte  ;  benevens  en  daarmee  samen- 
hangende  optnerking  omtrent  het  verband  tusschen  optisch  actief  vermogen  en 
chemische  constitutie  vanorganischeverbindingen;  Utrecht,  iS;4.  At  the  end  the  pa  per 
is  signed  September  5,  1874,  J.  H.  van 't  Hoff.  An  abstract  from  this  article 
appeared  in  1875  in  Bull.  Soc.  Chim.  [2],  23,  295.  Then  followed  :  i.  La  chimie  dans 
1'espace,  par  J.  H.  van  't  Hoff,  Rotterdam,  1875  :  2-  Die  Lagerung  der  Atome  im 
Raurn,  a  German  translation  of  the  last  by  Dr.  F.  Hermann,  Braunschweig  1877;  3. 
Dix  annees  dans  1'histoire  d'une  theorie,  par  J.  H.  van  't  Hoff,  Rotterdam  1887.;  4. 
Stereochimie,  by  W.  Meyerhofer,  a  German  edition,,  essentially  of  the  Dix  annees, 
etc.,  Leipzig  and  Vienna,  1892  ;  5.  Die  Lageruug  der  Atorne  im  Raum,  von  J.  H.  van  't 
Hoff,  2nd.  ed.,  Braunschweig,  1894. 

3  Le  Bel :  First  paper  :  Sur  les  relations  qui  existent  entre  les  formules  atomiques 
des  corps  organiques  et  le  pouvoir  rotatoire  de  leurs  dissolutions.  Bull.  Soc.  Chim., 
[2]  22,337,  November  number,  1874.  Then  following  papers:  Bull.  Soc.  Chim.  [2], 
23.  338  (2875)  ;  25,  546  (1876)  ;  27,  444  (1877)  ;  33,  106  (1880)  ;  37,  300  (1882)  ;  [3!,  7,  164  ; 
8,613(1892);  Compt.  rend.,  89,  312  (1879);  92,  843,  (1881)  ;  no,  144  (1890);  112,  724 
(1891)  ;  114,  504,417  (1892). 


48          ROTATING    POWER    AND   CHEMICAL   CONSTITUTION 

contrary,  through  Pasteur's  idea  of  molecular  dissymmetry, 
found  gradually  decided  confirmation  through  experiment, 
and,  as  is  well  known,  the  later  developments  of  the  theory, 
especially  the  views  advanced  by  van  't  Hoff  on  the  arrange- 
ment of  the  atoms  in  space,  have  created  a  new  epoch  in  the 
science,  that  of  stereochemistry. 

In  this  book  we  are  concerned  only  with  those  portions  of 
the  van't  Hoff-LeBel  theory  which  are  directly  connected 
with  optical  activity,  and  these  will  be  but  briefly  discussed  as 
they  are  found  explained  in  all  text-books  of  stereochemistry 
and  organic  chemistry. 

The  fundamental  points  in  the  theory  are  as  follows  : 

i.  Consider  in  a  compound  of  the  type,  CR4,  the  carbon 
atom  situated  in  the  center,  and  the  four  elements  or  groups 
joined  to  it  situated  at  the  corners  of  a  tetrahedron,  then  in 
case  the  four  groups  are  all  different,  the  resulting  solid 
formula  CCR^RgRJ  will  possess  no  plane  of  symmetry,  and 
must  exist  in  two  non-superposable  forms  of  which  one  is  the 
mirror  image  of  the  other.  According  to  this  view,  everybody 
whose  structural  formula  possesses  a  so-called  asymmetric 
carbon  atom,  that  is,  one  which  is  combined  with  four  differ- 
ent atoms  or  groups,  must  be  optically  active  and  appear 
in  a  right-  and  left- rotating  form  of  equal  rotating  powrer. 
Experience  has  shown  further  that  equal  weights  of  the 
two  modifications  can  unite  to  form  an  inactive  compound  or 
mixture  (racemic  body)  which  by  various  means  can  be  split 
up  into  the  active  components. 

Asymmetric  carbon  atoms  (*C)  can  appear  in  all  direct 
methane  derivatives,  and  chain  structure  molecules  ;  in  benzene 
derivatives  they  can  exist  only  in  the  side  chains,  but  in 
hydrated  cyclic  compounds  also  in  the  nucleus.  Examples 
are  found  in  the  list  of  active  substances  given  in  §  8 ;  a  few 
other  cases  may  be  referred  to  here,  from  which  it  will  be  seen 
that  of  the  four  radicals,  two  may  be  combined  between  them- 
selves (propylene  oxide),  or  one  of  the  same  with  two 
different  asymmetric  carbon  atoms  (phenoxacrylic  acid)  ; 
further,  that  the  asymmetry  of  a  carbon  atom  may  depend  on 
remotely  situated  groups,  and  not  necessarily  on  those  imme- 
diately connected  (limonene,  menthene)  : 


THEORY   OF   VAN  'T    HOFF   AND   LE  BEL  49 

Limonene. 
Propylene  oxide.  CH3x      ,CH2  Menthene. 

CH  O  f  H         CH, 

/       \     I  *PW  *O 

TT/          Xr^TT  \-jn~  v, 

H  CH2  /x  /x 

H2C        CH2  H2C        CH2 
Phenoxacrylic  acid. 

C6H5V  /C02H  HC        CH2  H2C        CH 

Vc— *c<  \\/  "  \^ 

H/     X/   XN  C  C 

O  I  I 

CH3  C3H7 

2.  In  substances  which  contain  two  asymmetric  carbon 
atoms  and  whose  molecules,  like  that  of  tartaric  acid, 
CO2H— *CHOH— *CHOH— CO2H,  are  built  up  of  two  similar 
halves,  there  must  be,  according  as  these  halves  show  the  same 
or  opposite  rotations,  besides  the  right-  and  left-rotating  forms, 
a  third  inactive  form  depending  on  this  intramolecular  com- 
pensation, and  which  cannot  be  resolved  into  active  com- 
ponents. Such  an  inactive  form  is  not  possible  when  the  half 
molecules  are  dissimilarly  constructed,  but  in  this  case,  four 
active  isomers  may  be  expected,  each  two  possessing  equally 
strong,  but  oppositely  directed  rotations.  If  a  compound  con- 
tains several  asymmetric  carbon  atoms,  by  addition  or  sub- 
traction of  the  effects  of  the  single  groups,  a  large  number  of 
unequally  strong  active  modifications  may  result,  two  of  which 
again  in  each  case  belong  together  as  antipodes,  and  finally 
the  existence  of  some  definite  number  of  inactive  compensation 
forms  may  also  be  expected. 

In  all  such  cases,  consideration  will  show  how  many  of 
these  optical  isomers^must  exist  when  the  structural  formula 
of  the  substance  is  known.  The  method  of  making  such  a 
computation  will  be  shown  in  the  next  chapter  on  Optical 
Modifications. 

With  the  ethylene  derivatives  having  four  different  radicals, 
R1R2C=CR3R4,  the  four  groups  must  lie  in  one  plane  if  we 
consider  the  carbon  atoms  united  by  an  edge  of  the  tetra- 
hedrons containing  them,  and  no  asymmetry  is  possible.  In 
fact,  all  ethylene  derivatives  have  been  found  to  be  inactive,1 

1  Le  Bel  (Bull.  Soc.  Chim.  [3],  8,  613)  had  considered  optical  activity  possible  in 
unsaturated  compounds,  and  Perkin  (Jour.  Chem.  Soc.,  53,  695)  believed  he  found 
this  in  chlorfumaric  and  chlormaleic  acids,  CO2H— CC1=CH— CO2H.  Walden,  how- 
ever, showed  the  error  in  these  observations  (Ber.  d.  chem.  Ges.,  26,  210). 

4 


50          ROTATING    POWER    AND   CHEMICAL    CONSTITUTION 

even  when  made  from  active  compounds,  as  for  example, 
fumaric  and  maleic  acids  from  malic  acid,  bromcinnamic 
acid,  C6H5— CBr=CHCO.2H,  from  the  dibromide, 
C6H5— CHBr— CHBr.CO,H,  and  others.  Likewise,  no  asym- 
metry is  possible  when  in  bodies  of  the  type,  R,R2C=CR3R4 
an  even  number  of  doubly  linked  carbon  atoms  is  introduced. 
But,  on  the  other  hand,  as  van  't  Hoff  remarked,1  asymmetry 
and  optical  activity  appear  if  the  number  of  added  carbon 
atoms  is  uneven,  inasmuch  as  the  four  radicals  then  stand 
crossed,  as  is  the  case  in  the  tetrahedron.  The  simplest 
bodies  of  this  kind  would  be  the  propadiene  (allene)  deriva- 
tives ;  observations  on  such  substances  are  wanting  as  yet. 

As  van  't  Hoff  pointed  out,2  cyclic  compounds  present  cer- 
tain definite  conditions  of  asymmetry,  and  to  begin  with,  we 
have  the  derivatives  of  tri-  and  tetramethylene,  but  active 
bodies  belonging  here  are  not  yet  known.  But  many  such 
appear  in  the  six  member  rings,  that  is  in  the  di-,  tri-  and 
hexa-hydrated  benzene  derivatives.  Among  the  last  inositol,:i 

/CH.OH— CH.OH, 

CH.OH<  >CH.OH, 

XCH.OH— CH.OH/ 

offers  an  example  in  which  the  existence  of  asymmetric 
carbon  is  not  apparent  from  the  formula,  and  in  which  the 
asymmetry  and  the  mirror  image  form  appear  only  when  the 
position  of  the  H  and  OH  above  and  below  the  plane  of  the 
carbon  ring,  that  is  to  say,  the  cis  and  trans  isomerism,  is  taken 
into  consideration;  anything  further  concerning  this  belongs 
in  the  field  of  stereochemistry.  Benzene  derivatives  which  are 
not  hydrides  can  hold  asymmetric  carbon  atoms  in  the  side 
chains. 

Confirmation  of  the  van 't  Hoff -Le  Bel  theory  has  come 
gradually,  and  in  many  different  ways.  It  has  been  found 
that  without  exception,  activity  is  connected  with  the  pres- 
ence of  asymmetric  carbon,  and  that  in  bodies  in  which  this  is 
lacking,  rotating  power  is  not  found.  For  a  number  of  bodies 
of  the  last  class,  such  as  N-propyl  alcohol,  styrol,  /2-picoline 
and  others,  in  which  activity  was  claimed,  it  was  found  that 

1  "  Lagerung  der  Atome  im  Raum,"  2nd.  ed.  (1894),  pp.  68  to  76. 

*  Loc.  cit..  p.  83  1094. 

*  See  Bouveault :  Bull.  Soc.  Chim.  [3],  n,  144  (1894). 


THEORY    OF    VAN  'T    HOFF   AND    LE  BEL  51 

this  assertion  was  an  error.  Through  direct  experiments,  the 
appearance  or  disappearance  of  optical  activity  by  formation 
or  destruction  of  asymmetric  carbon  atoms  was  further  shown. 
Le  Bel  first  proved  this  by  the  conversion  of  active  amyl 
iodide,  CH3.HC*.C2H5.CH.J,  into  inactive  methyldiethyl 
methane,  CH3.C.H.C2H5.C2IV  Then  Just2 obtained  from  the 
same  amyl  iodide,  by  action  of  zinc  and  hydrochloric  acid 
inactive  dimethylethyl  methane,  (CH3)2.C2H5.C.H,  but  by 
action  of  ethyl  iodide  and  sodium  he  obtained  active  methyl- 
ethylpropyl  methane,  CH3.C2H5.C3H..*C.H  ;  alsb,  by  heating 
with  sodium,  active  diamyl, 

C2H5.CH3.H.*C.— CH2—  CH2.— *C.H.CH3.C2H5. 
Further,  it  was  shown  that  for  the  existence  of  optical  activity 
the  nature  of  the  four  radicals  combined  with  the  asymmetric 
carbon  atom  is  a  matter  of  no  consequence.  It  was  formerly 
observed  that  the  introduction  of  a  halogen  led  often  to  a  dis- 
appearance of  activity  ;  thus  from  left-rotating  malic  acid, 
inactive  bromsuccinic  acid,  (Kekule),3  from  left- 
rotating  mandelic  acid,  inactive  phenylbromacetic  acid, 
C6H5.*CHBr.CO,H  ( Easterfield )  /  and  iromd-  and  /-isopropyl- 
phenylglycolic  acid,  inactive  isopropylphenylchloracetic  acid, 
(C6H4.C3H7)(H)^C(Cl)(CO2H),(Fileti),5were  obtained.  As 
was  later  found,  the  cause  of  the  inactivity  of  these  products 
lay  in  the  fact  that  racemic  forms  wrere  produced  by  reason  of 
the  high  reaction  temperature.  By  keeping  this  as  low  as 
possible,  these  halogen  bodies  were  obtained  in  rotating  con- 
dition. This  was  shown  particularly  by  Walden,  who  prepared 
an  active  chlorsuccinic  acid  from  malic  acid  by  action  of  phos- 
phorus pentachloride  with  addition  of  chloroform,  and  later 
from  sarcolactic  acid,  ethyl  tartrate,  and  mandelic  acid,  a  large 
number  of  chlorine  and  bromine  derivatives,  such  as  methyl 
chlorpropionate,  ethyl  brommalate,  phenylchloracetic  acid, 
and  others  which  all  possessed  optical  activity.6  Finally,  the 

1  Le  Bel :  Bull.  Soc.  Chitn.  [2],  25,  546  (1876). 

2  Just  :  Ann.  Chem.  (Liebig),  220,  146  (1883). 

*  Kekule  :  Ann.  Chem.  (Liebig),  130,  25  (1864). 

4  Easterfield  :  Jour.  Chem.  Soc.,  59,  75  (1891). 

5  Fileti :  Gazz.  Chim.,  22,  II,  405;    J.  prakt.  Chem.  [2],  46,  562. 

6  Walden  :  Ber.  d.   chem.   Ges.,   26,   214  (1893).     See   further  Le   Bel  :  Bull.   Soc. 
Chim.,  9,  674  (1893)   and   Ber.   d.   chem.    Ges.,   28,    1923   (1895)  ;  also  Walden :  Ber.  d. 
chem.  Ges.,  28,  2766. 


52          ROTATING    POWER    AND    CHEMICAL   CONSTITUTION 

fact  was  fully  explained  why  many  bodies  exist  which  contain 
asymmetric  carbon  atoms,  but  are  nevertheless  inactive.  In 
some  cases  it  was  shown  that  they  are  racemic  forms,  inasmuch 
as  they  are  resolvable  into  active  compounds  ;  in  other  cases, 
as  mesotartaric  acid,  dulcitol;  and  mucic  acid,  they  contain  two 
similarly  constituted  halves,  and  the  inactivity  follows  from 
the  opposite  rotating  power  of  these.  In  a  third  group  of 
asymmetric  substances  it  was  found  that  they  possess  a  very 
weak  rotating  power,  and  in  order  to  recognize  this,  either  a 
very  long  column  must  betaken,  or,  as  in  the  case  of  mannitol, 
some  indifferent  substance  (boric  acid)  must  be  added  to 
increase  it.  It  appears  therefore,  that  in  all  cases  the  views 
of  van  't  Hoff  and  Le  Bel  are  found  to  agree  with  experience, 
and  that  when  apparently  a  contradiction  was  found  (limonene),1 
later  investigations  removed  this.  The  doctrine  of  asym- 
metric carbon  atoms  may  be  looked  upon  as  one  of  the  best 
established  of  chemical  theories. 

14.  Asymmetric  Nitrogen  and  Sulphur. — Compounds  of  triad 
nitrogen  with  radicals  different  from  each  other  appear  always 
to  be  inactive  ;  attempts  to  split  up  the  tartaric  acid  salts  of 
ethylbenzylamine  (Kraft),-'  benzyl  hydroxylamine  (Behrend 
and  Konig),3  methyl  aniline,  tetrahydroquinoline,  and  tetra- 
hydropyridine  (Ladenburg),4  have  led  to  no  result. 

On  the  other  hand,  an  active  compound  of  pentavalent 
nitrogen,  isobutylpropylmethylethylammonium  chloride  has 
been  obtained.  The  inactive  salt  directly  obtained  was 
split  up  by  Le  Bel5  by  aid  of  the  fungus  culture  method,  and 
a  left-rotating  chloride  ([«]„=  -7°  to  8°)  was  obtained, 
which  was  further  converted  into  active  chlorplatinate,  chlor- 
mercurate,  and  acetate.  The  chloraurate,  rotating  very  feebly 
to  the  left,  became  dextrorotatory  after  addition  of  hydro- 
chloric acid.  The  sulphate  was  found  to  be  inactive. 

More  recently  another  active  compound  of  pentavalent 
nitrogen  has  been  produced.  Wedekind6  attempted  to  resolve 

von  Baeyer  :  Ber.  d.  chem.  Gcs.,  37,  436;  Tiemann  and  Semmler  :  /bid.,  28,  3495. 

Kraft :  Ber.  d.  chem.  Ges.,  23,  2780  (1890). 

Behrend  and  Konif?  :  Ann.  Chem.  (Liehi^),  263,  184  (1891). 

Ladenburg :  Ber.  d.  chem.  Ges.,  26,  864  (1893). 

LeBel  :  Compt.  rend.,  112,  724  (1891). 

Wedekind  :  Ber.  d.  chem.  Ges.,  32,  517. 


ASYMMETRIC    NITROGEN   AND   SULPHUR  53 

a'-benzylphenylallylmethylammonium  hydroxide  by  com- 
bination with  tartaric  and  camphoric  acids,  but  without 
success.  Pope  and  Peachey,  however,  by  using  the  much 
stronger  dextrocamphor  sulphonic  acid,  which  they  have 
applied  in  several  other  cases,  succeeded  in  effecting  a  perfect 
resolution.1 

They  mixed  the  iodide  of  <*-benzylphenylallylmethyl- 
ammonium  with  the  silver  salt  of  dextrocamphor  sulphonic 
acid  in  molecular  proportion,  and  boiled  in  a  mixture  of 
acetone  and  ethyl  acetate.  After  separating  silver  iodide  by 
filtration,  the  liquid  left  deposited,  on  cooling,  a  crystalline 
mass  of  the  dextro-  and  levo-benzylphenylallylmethyl- 
ammonium  dextrocamphor  sulphonates.  This  was  crystallized 
from  acetone,  the  less  soluble  dextro  constituent  being 
readily  obtained  in  colorless  plates  melting  at  170°,  and  giving 
\_a~\D  --  -f-  44.4°.  For  the  /-salt  separated  from  the  mother- 
liquors  in  less  pure  form,  the  rotation  [tf]/>=  -  18.6°  was 
found.  By  double  decomposition  of  the  camphor  sulphonates, 

C6H5.CH2.N(C6H5)(C3H5)(CH3).S03.C10H150, 
the   authors   obtained   the   d-    and   /-iodides   and    bromides, 
C6H5.CH2.N(C6H5)(C3H5)(CH3)I,  or  Br. 

In  recent  years  many  attempts  have  been  made  to  resolve 
asymmetric  racemic  sulphur  compounds,  but  for  a  time  with- 
out success.  See  for  example  the  work  of  Aschan.2 

Very  lately,  however,  and  just  as  this  translation  is  going  to 
the  press,  Pope  and  Peachey"  have  applied  their  camphor 
sulphonic  acid  process  to  the  resolution  of  methylethyl- 
thetine  and  have  succeeded  in  separating  an  active  body  with 
the  sulphur  as  the  asymmetric  element.  The  authors  conclude 
from  their  work  that  a  large  number  of  other  elements  may  be 
found  to  behave  as  asymmetric  centers  of  optical  activity. 
Some  details  of  their  process  will  be  given  in  a  following 
chapter. 

Ammonium  derivatives  containing  two  similar  radicals  as 
the  chlorides  of  dimethylethylpropyl-,  methylethyldipropyl-, 
ethyldipropylisobutyl-,  and  ethylpropyldiisobutylammonium 

1  Pope  and  Peachey  :  J.  Chem.  Soc.,  75,  1127. 

-  Aschan  :  Ber.  d.  chem.  Ges.,  32,  988. 

3  Pope  and  Peachey  :  J.  Chem.  Soc.,  77,  1072. 


54  OPTICAL    MODIFICATIONS 

cannot  be  converted,  as  Le  Bel1  found,   into  active  forms  by 
the  action  of  fungi. 

Further  consideration  of  the  subject  of  asymmetric  nitrogen 
belongs  in  the  field  of  stereochemistry. 

V.     OPTICAL  MODIFICATIONS 

15.  The  fact  that  a  body  can  exist  in  a  right  rotating,  a  left 
rotating,  and  an  inactive  form  was  first  recognized,  as 
mentioned,  by  Pasteur  in  1848,  in  the  case  of  tartaric  acid. 
The  number  of  bodies  acting  similarly  was  increased  very 
slowly,  and  in  1879,  at  the  time  of  the  publication  of  the  first 
edition  of  this  book,  only  three  other  examples  could  be  given; 
mz.,  malic  acid,  camphor,  and  camphoric  acid. 

Already  in  1875,  van  't  Hoff,  in  his  "  Chimie  dansPespace," 
had  developed  the  general  formulas  by  which  the  number  of 
possible  stereoisomers  and  hence,  also,  optical  isomers  of  a 
body  could  be  calculated  from  the  number  of  asymmetric 
carbon  atoms  in  its  molecule.  For  a  long  time  the  observations 
available,  from  which  these  formulas  could  be  tested,  were 
entirely  too  scanty,  and  only  in  the  last  few  years,  the  great 
investigations  of  E.  Fischer,  on  the  members  of  the  sugar 
group,  have  furnished  material  which  demonstrated  com- 
pletely the  correctness  of  the  theoretical  predictions.  Obser- 
vations were  multiplied  also,  in  other  classes  of  compounds 
and  as  the  table  of  active  substances  given  in  §  8  shows,  there 
are  now  over  100  such  bodies  known  in  different  optical 
modifications. 

However,  there  is  still  a  very  large  number  of  active  bodies, 
over  300  in  fact,  which  are  known  only  in  one  form,  some 
right,  some  left  rotating.  This  is  true  of  whole  groups  of 
bodies  as  the  polysaccharides,  natural  glucosides,  starch 
varieties,  alkaloids,  bitter  principles,  bile  acids,  and  proteids. 
Without  doubt,  most  of  these  contain  several  asymmetric 
carbon  atoms,  and  must  exist  in  different  forms  with  different 
rotating  powers  as  well  as  in  inactive  modifications. 

1  Le  Bel  :  Compt.  rend.,  na,  724 


CALCULATION   OF   NUMBER  55 

A.    Calculation  of  the  Number  of  Optical  Modifications  of  a  Compound 
from  the  Number  of  Asymmetric  Carbon  Atoms  Contained  in  It. 

16.  If  we  divide  the  compounds  consisting  of  a  chain  of 
singly  linked  carbon  atoms  into  the  three  classes  given  below, 
the  number  of  possible  stereoisomers  or  optically  active  and 
inactive  forms  is  shown  in  the  following  expressions  in  which  : 

n  =  the    number    of    asymmetric    carbon    atoms    in    the 

compound. 
N—  the   whole   number    of   possible    isomers,     which   are 

divided  into 

i  3=  inactive,  non-separable  modifications,  and 
a  =  active  forms,  which  occur  in  pairs  as  optical  antipodes 

with  equally  strong  opposite  rotations.     These  lead  to 

r  —  —  inactive  separable  racemic  modifications. 

First  class  :  n  even  or  odd.  Structural  formula  not  in  two 
equal  halves. 

If  RRV  represent  the  terminal  radicals,  and  a,  d,  the  radicals 
combined  to  the  middle  carbon  atoms,  the  general  type  is 


For  example  : 

Malic  acids CO2H— *CH.OH— CH2— CO2H 

Phenyl-tf-chlorlactic  acids C6H5— *CH.OH— *CHC1— CO2H 

Pentoses    CH2OH— *CH.OH— *CH.OH— *CH.OH— CHO 

Hexonic  acids CH2OH— (*CH.OH)4— CO2H 

Bodies  belong  here  in  th£  chain  of  which  there  is  at  some 
point,  a  carbon  atom  which  is  not  asymmetric  (CH2,  CO2,  CO). 
For  example  : 

Butylchloralaldol 

CH3— *CHC1— CC12— *CH.OH— *CH(CHO)— *CH.OH— CH3 

In  all  such  cases  we  have 

(I)1  N  =  2n         a  =  2  i  ==  o. 

1  The  expressions  (I)  and  (II)  were  first  proposed  by  van  't  Hoff  ("  I^a  chimie  dans 
e,"  1875,  p.  9  and  12)  and  the  second  one  is  also  found  in  this  form  : 

n 

N=£  -2"-22or2^- 

2 

Attention  was  first  called  to  formula  (III)  by  E.  Fischer  (Ann.  Chem.  (Uebig), 
270,  67  (1891)).  These  formulas  are  derived  from  the  theorems  on  permutation  and 
combinations,  attention  being  paid  to  the  conditions  obtaining  for  various  reversed 
and  reflected  image  forms. 


OPTICAL   MODIFICATIONS 


Therefore  : 


n  = 

i 

2 

3 

4 

5 

6 

N  =  a  = 

2 

4 

8 

16 

32                    64 

r  = 

I 

2 

4 

8               16               32 

Second  class  :  n  even.  Structural  formula  in  two  equal 
halves.  The  type  is 

R—(*C*l>)t,vv.-R 

For  example  : 

Tartaric  acid CO,H— *CH.OH— *CH.OH— CO2H 

Syra.  dimethylsucciuic  acid  . . . .  CO2H— *CH(CH3)—  *CH(CH3)— COaH 

Hydrobenzoin C6H5— *CH.OH— *CH.OH— C6H5 

Hexitols CH,OH— ( *CH.OH)4— CH..OH 

Tetraoxydicarboxylic  acid CO2H— (*CH.OH)4— CO,H. 

Bodies  are  found  here  with  symmetrically  halved  structural 
formulas  which  contain  in  the  middle,  an  even  number  of 
non-asymmetric  carbon  atoms.  For  example  : 

DimethyladipicacMs,  CO2H-*CH(CH8)-CH2-CH2-*CH(CH8)-CO2H 
Diallylbromides,  CH,Br— *CHBr— CH,— CH,— *CHBr— CH,Br. 
We  have  in  the  second  class  : 


(II) 


a  =  2' 


Therefore,  when 


"I    " 

4 

6 

8 

<=] 

i=  I 

r~  \ 

3 

2 
I 
I 

10 

8 

2 

4 

36 
32 

4 
16 

136 

128 
8 
64 

Third  Class  :  n  uneven.     Structural  formula  equally  halved, 
after  excluding  the  middle  carbon  group.     The  type  is 

*— (*CaJ)3,5l7,...—  R 
Examples  : 

Trioxyglutaric  acids,  CO2H—  *CH.OH— °CH.OH— *CH.OH— COaH 
a-Glucoheptitol,  CH,.OH— (*CH.OH),— °CH.OH-(*CH.OH)2-CH.2.OH 

CH:<         H         CH3 

Dimethyltricarballylic  acid    H— *C °C *C— 1 1 


CO 


aH   C02H 


CO,H 


CALCULATION   OF    NUMBER 


57 


In  these  cases  °C,  the  middle  atom  of  the  chain,  is  : 

Asymmetric  (active)  when  the  other  parts  of  the  chain, 
the  equal  halves,  are  asymmetric  similarly,  that  is,  have 
the  same  direction  of  rotation  ; 

Symmetric  (inactive)  when  the  two  other  parts  of  the 
chain  are  oppositely  asymmetric,  and  therefore  neutralize 
each  other  in  their  rotating  power. 

Under  both  circumstances  when  the  middle  atom,  °C.  is 
included  in  the  number  n,  we  have  the  following  formula  for 
calculating  the  isomers : 


(III) 


N=2l 


1=  2 


n  —  i 
2    . 


From  this  it  follows  that  for  : 


n  = 

3 

5 

7 

9 

N  = 

4 

]6           64 

256 

a  = 

2 

12           56 

240 

i  = 

2 

4 

8 

16 

r  — 

I 

6        28 

120 

In  deriving  the  different  stereoisomers  of  a  body,  it  is  con- 
venient to  employ  the  method  of  representation  proposed  by 
E.  Fischer,1  which  consists  in  this,  that  the  solid  model  of  the 
molecule  (built  up  by  the  aid  of  the  well-known  rubber 
carbon  atom  models)  is  placed  in  such  a  manner  over  the 
plane  of  the  paper  that  all  the  carbon  atoms  are  found  in  a 
straight  line,  and  the  radicals  combined  with  them  (H  and 
OH ) ,  stand  to  the  right  and  left  above  the  plane.  Then  the 
projection  of  such  a  structure,  for  example,  that  of  </-glucose 
is  shown  in  the  following  diagram,  la,  and  that  of  /-glucose 
by  the  mirror  image  I£.  A  more  contracted  method  of 
representation  is  shown  in  II  and  III,  where,  for  the  last  case, 
H  =  •  and  OH  =  x  . 

1  Fischer  :  Ber.  d.  chera.  Ges.,  24,  2683. 


CHO 

CHO 

CHO 

CHO 

1 

1 

H—  C—  OH 

HO—  C—  H 

HOH 

HOH 

1 

1 

HO—  C—  H 

H—  C—  OH 

HOH 

HOH 

H—  C—  OH 

HO—  C—  H 

HOH 

HOH 

1 

i 

H—  C—  OH 

HO—  C-H 

HOH 

HOH 

I 

| 

| 

CH2OH 

CH2OH 

CH2OH 

CH2OH 

58  OPTICAL   MODIFICATIONS 

la  Ib  II  III 

JT)  JT> 

•  X         X» 

x«       «x 

•X        X« 
•X        X« 

/?!  R-L 

The  Inactive  Non- Separable  Modifications  are  distinguished  in 
the  following  configuration  formulas  by  this,  that  the  latter 
may  always  be  cut  by  a  horizontal  line  into  two  equal  halves  of 
which  the  lower  one  is  the  mirror  image  of  the  upper.  The 
compensation  existing  within  the  molecule  is  illustrated  by 
this,  fpr  if  in  Diagram  I,  below,  a  spiral  be  drawn  through  the 

four  radicals  in  the  direction,  *  ^  R  (  •  x  &)  in  the  uPPer 
half  of  the  figure  it  will  be  turned  to  the  right,  and  in  the 
lower  to  the  left.  In  compounds  which  have  in  the  chain  an 
uneven  number  of  carbon  atoms,  the  cut  passes  through  the 
middle  (not  asymmetric)  one.  Such  inactive  molecules  may 
be  represented  by  the  following  diagrams  : 


I 

R 
X» 

2 

R 
X» 
•X 

3 

R 
X« 
X  • 

4 

•  R 
x» 
x« 

•  X 

5 

R 
X« 
•  X 

X. 

x» 

R 

•  X 

x« 

R 

x» 

R 

x» 
x« 

R 

•X 

x» 

R 

In  what  follows  the  derivation  of  the  possible  optical  modi- 
fications for  chain  structure  molecules  with  n  —  i,  2,  3,  4,  5  will 
be  carried  through  and  illustrated. 

I.   n=i. 
First  Class  : 

N=  a  =  2  i=  o  r=  i 

For  example  : 

CH,  CH3  CH2.COOH  CH2.COOH 

H— C— OH       HO— C— H          H— C— NH2  NH2— C— H 

III  I 

CH2OH  UI,OH  COOH  COOH 


Right  and  left  propyleneglycol.      Right  and  left  aspartic  acid. 


CALCULATION   OF   NUMBER  59 

II.       n  =  2. 
A.   First  Class: 

N  =  a  =  4  i  =  o          r  =  2 

The  four  possible  active  combinations,  of  which  each  pair 
form  antipodes,  are: 

12  34 

R             R  R            R 

x«           x»  »x          x» 

x«           x»  x»           »x 


An  example  of  this  is  furnished  by  cinnamic  acid  dibromide 
of  which  the  four  active  as  well  as  the  two  racemic  forms  are 
known: 


C6H5  C6H5  C6H5 

BrH  HBr  HBr  BrH 

BrH  HBr  BrH  HBr 

COOH  COOH  COOH  COOH 


Which  of  these  configurations  belongs  to  each  isomer  has 
not  been  established. 

The  same  conditions  must  appear  with: 

Phenyl-a-chlorlactic  acid C6H5— CH.OH— CHC1— CO2H, 

Phenyl-jS-chlorlactic  acid C6H5— CHC1— CH.OH— CO2H, 

Trioxybutyric  acids CH2OH— CH.OH— CH.OH— CO2H,  etc. 

B.   Second  Class: 

N  —  3         a  =  2         t  =  i         r  =  i 

If  R  =  Rl  of  the  four  combinations  given  under  A,  i  and  2 
will  be  identical,  as  can  be  shown  by  rotating  the  diagram 
(turning  it  upside  down),  and  there  remain: 

R  R  R 

x«  «x  x» 

x»  x«  -x 

R  R  R 

Inactive.  Oppositely  active. 


6o 


OPTICAL   MODIFICATIONS 


Example  : 
COOH 

COOH 

COOH 

1 
HOH 

HOH 

HOH 
HOH 

HOH 
HOH 

COOH 

COOH 

COOH 

Meso- 


Right 


Left 


tartaric  acid,     tartaric  acid,     tartartic  acid. 
III.      n  ==  3. 


A.  First  Class: 

N=  a  =  8 
We  have: 


=  o 


-f-  tartaric  acid 

—  tartaric  acid 

Racemic  acid. 


r==  4 


I 

2 

34                  56                    78 

R         R 

R         / 

?               R          R                 R 

R 

x« 

X 

,     »X          X 

X»             -X                    X« 

•X 

x»        »x 

X  •            • 

X                 «X           X»                     X» 

•X 

X* 

X 

x»         »x           x»         »x              »x      x« 

R,        R, 

A>                 />                        T)                  r>                             r>               r> 
1               ••'l                      **\              •**•!                          -*M             **| 

^""  '         '  ™V  J 

Example: 

RI                                    R 

Pentoses 

..  .  .CH  OH    (Cl 

H.OH)3—  CHO 

Pentonic  acids 

.  .  .  -CH  OH  (C] 

S.OH)3—  COOH 

I                   2 

3              4 

5              6                 7 

8 

R             R 

R             R            R            R               R 

R 

HOH          H 

OH 

HOH  HO 

H       HOH          H 

HOH 

HOH 

HOH         H 
HOH         H 

OH 
OH 

HOH          II 
HOH         H 

OH      HOH    HO 

OH   HOH         H 

HOH 
HOH 

HOH 
HOH 

A,            j 

t| 

Rl            J\ 

'i            ^i            ^i              A'\ 

^i 

/-Ribose.  Unknown.  /-Arabinose.  rf-Arabi-J  Unknown.  /-Xylose.    Lyxose.    Unknown. 

/-Ribonic                        /-Arabonic      nose.  /-Xylonic  lyyxonic 

acid.                                 acid.  acid.         acid. 

B.    Third  Class: 

TV"  ==  4          a  —  2  1  =  2          r  =  l. 

Of    the   configurations   given   under   A   the   following   are 
identical  when  R  =  Rr- 

i  with  2  4  with  7 

3     "     8  5     "     6 


CALCULATION    OF    NUMBER 


6l 


and  there  remain: 


5 

R 
x» 
•  x 

X- 

R 


Inactive.        Oppositely  active.         Inactive. 


I 

3 

4 

R 

R 

R 

x« 

•  X 

X« 

x« 

x» 

•X 

x. 

X  • 

•X 

R 

R 

R 

Example  : 

Pentitols 

Trioxyglutaric  acids . 


R 

R 

R 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

R 
Adonitol. 
Ribotrioxy- 
glutaric  acid. 
Inactive. 

# 

R 

/-Arabitol. 
/-Trioxy- 
glutaric acid. 

Unknown. 

•  CH,OH— (CH.OH)3— CH2OH 
COOH— (CH.OH)3— COOH 

R 

HOH 
HOH 

HOH 

R 

Xylitol. 
Xylotrioxy- 
glutaric  acid. 

Inactive. 


IV.       n  —  4. 
A.   First  Class: 

N  =  a  ==  16,         i  =  o, 


r  = 


i 

2 

3 

4 

5 

6 

7 

8 

R 

R 

R 

R 

R 

j? 

J? 

R 

x  • 

•X 

•X 

x« 

x» 

•  X 

x» 

•X 

x» 

•X 

x» 

•X 

•X 

x» 

x» 

•X 

X- 

•X 

X- 

•X 

x» 

•X 

•X 

X  • 

x» 

•X 

x« 

•X 

X* 

•X 

x« 

•X 

R\ 

*1 

^1 

Kl 

*, 

^1 

^1 

*, 

9 

10 

II 

12 

13 

14 

15 

16 

y? 

R 

^ 

A» 

R 

R 

R 

/? 

x« 

•X 

•X 

x« 

•X 

X  • 

•  X 

x» 

x» 

• 

•X 

x« 

x» 

•  X 

X  • 

•X 

x. 

•  X 

X  • 

•  X 

•  X 

X  • 

x« 

•X 

•  X 

^1 

X  • 

*, 

X  • 

#, 

•X 

*, 

x» 

•X 

•X 

*1 

x» 

x* 

62  OPTICAL   MODIFICATIONS 

Of  these  sixteen  active  configurations,  in  the 


R 


Hexoses  ..................  CH2OH—  (CH.OH),—  CHO 

and         Hexonic  acids  .............  CH2OH—  (CH.OH),—  COOH 

the  following  are  known: 


5 

6 

7 

8 

9 

R 

R 

R 

R 

R 

HOH 

H 

OH 

HOH 

HOH 

HOH 

HOH 

HO 

H 

HOH 

HOH 

HOH 

HOH 

H 

OH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

Glucose,  gluconic  acid. 


d  I  d 

Talose, 
Gulose,  gulonic  acid,     talonic  acid. 


II 

12 

13 

M 

15 

16 

R 

R 

R 

R 

R 

R 

HOH 
HOH 

HOH 

HOH 

j 

HJOH 

HOH 

HOII 
HOH 

HOH 
HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

#* 

R\ 

^i 

#1 

^i 

* 

Mannose,  mannonic  acid.      Idose,  idonic  acid. 


B.   Second  Class: 
N=  10 


a  =  8 


I  =  2 


Galactose,  galatonic 
acid. 


=  4 


This  number  of  isomers  follows  from  the  configurations 
given  under  A  when  R  is  taken  equal  to  /?p  because  then  there 
become  identical: 


i   with  2 

3  "     10 

4  "       9 


5  with  8 

6  "     7 
15      "  16 


CALCULATION   OF    NUMBER 

There  remain  then: 

i  —  (3,  4)  —  (5,  6)  —  (u,  12)  —  (13,  14)  —  15. 
We  have  here 

Hexitols CH2OH— (CH.OH)4— CH2OH 

and         Saccharic  acids COOH— (CH.OH)4— COOH, 

of  the  last  of  which  the  ten  forms  are  known  : 


I 
R 

3 
£ 

4 
R 

1 

5 
R 

6 
R 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 
HOH 

HOH 
HOH 

HOH 

HOH 

HOH 
HOH 

HOH 
HOH 

R 

Inactive 

Allo- 
mucic  acid. 

R 
I 

R 

d 

R                    R 

I                     d 

Sorbitol. 
Saccharic  acid. 

Talitol. 
Talomucic  acid. 

ii 
R 

12 

R 

13 

R 

1 

14 
R 

15 
R 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

HOH 

OHH 

HOH 

HOH 

HOH 

HOH 

HOH 

R 

I 

R 

d 

R 

d 

R 

I 

R 
Inactive. 

Dulcitol. 
Mucic  acid. 

Mannitol. 
Mannosaccharic  acid. 

Iditol. 
Idosaccharic  acid. 

V.     »=5. 

A.   First  Class  : 

N  ==  a  =  32  i  =  o  r  =  16. 

The  thirty-two  possible  comb  inations  are  as  follows,  leaving 
out  the  symbols,  R  and  Rl  : 


I 

2 

3 

4 

5 

6 

7 

8 

x» 

•X 

•  X 

x« 

x» 

•X 

x» 

•X 

x» 

•X 

x« 

•X 

•  X 

x« 

x« 

•X 

x» 

•X 

x» 

•X 

x» 

•X 

•X 

x» 

x« 

•X 

x» 

•X 

X  • 

•  X 

x^ 

•X 

x» 

•X 

x» 

•X 

x« 

•  X 

x« 

•X 

64 


OPTICAL   MODIFICATIONS 


9            io 
X-             »X 

x«          »x 
x»         «x 

•X           X« 

x«         «x 

II                 12 

x«         «x 
x»         «x 
x«          -x 

•X           X» 

13           H 
•X           X« 
•  X           X» 

x«         «x 
x»         »x 
>o  »x 

21                  22 

x»         «x 

•  X           X» 
•X           X» 

x»         «x 

29       30 

X  •             »X 
X»             oX 
•X           X« 

x«         «x 

•X           X» 

15             16 
•X           X» 

x»         »x 

•X           X« 

x»         »x 

X*             «X 

23         24 
x»         ^x 

•X           X« 

x«         »x 

•X           X« 

x«         «x 

31        32 

x«         «x 
x«         »x 
x«         «x 

•X           X« 
•X           X« 

17            18 
•X           X» 

x«         «x 
x«         «x 

•  X           X» 

x«         »x 

19                 20 
•X           X» 

x»         »x 
x«         «x 
x«         «x 

•  X           X» 

25         26 
x«         »x 

•X           X» 

x«         «x 
x«         «x 

•X           X» 

27          28 
x«         »x 
x»         «x 

•X           X« 
•X           X« 

x«         «x 

Of  bodies  belonging  here,  but 

ing  to  : 
8                          8 
CHO                     COOH   . 

HOH                    HOH 

few  are  known,   correspond- 

16                      16 
CHO                     COOH 

HOH                     HOH 

HOH 
HOH 

HOH 

HOH 

HOH 
HOH 

HOH 
HOH 

1  1  OH 

HOH 

HOH 

HOH 

1  1  OH 

HOH 

HOH 

HOH 

CO.;OH 

o-Gluco- 
heptose. 

CH./)H 
a-Gluco- 
heptonic  acid. 

CH2OH 
/3-Gluco- 
heptose. 

CH2OH 
jS-Gluco- 
heptonic  acid. 

B.    Third  Class  : 

N  -  -  1  6 


12         1  =  4. 


r  --  6 


When  R  --  R 
are  identical  : 

I  with    2 

3  "      12 

4  "      ii 

5  "        TO 

6  "       9 

7  "       8 


of  the  forms  given  under  A,   the  following 


13  with  32 

1  8  with  25 

M  "  3i 

19  "  20 

15  "  30 

21   "   28 

16  "  29 

22   "   27 

17  "  26 

23  "  24 

CALCULATION   OF   NUMBER  65 

There  remain  then,  as  can  be  calculated  from  the  formulas, 
sixteen  configurations  ;  viz. ,  six  active  pairs  and  four  inactive 
forms.  These  are  : 


I 

3 

4 

5 

6 

7 

13 

14 

x« 

•X 

x» 

x« 

•X 

x^ 

•X 

x» 

x» 

X  • 

•X 

•X 

x« 

x» 

•X 

x» 

X  • 

X  • 

•X 

x» 

•X 

•X 

x« 

•X 

x« 

x« 

•X 

X  • 

•X 

x» 

x» 

•X 

X  • 

x» 

•X 

X  • 

•X 

x» 

x» 

•X 

Inactive.        Active.  Active.         Inactive.       Active. 


15 

16 

17 

18 

19 

21 

22 

23 

•X 

x« 

•X 

x« 

•X 

x» 

•X 

x» 

x« 

•  X 

x« 

•X 

x« 

•X 

x» 

•X 

•X 

x« 

x« 

•X 

x« 

•X 

x« 

x» 

x« 

•X 

•X 

x« 

x« 

x» 

•X 

•X 

x» 

v.  

•X 

x« 

^  

•X 

•X 

x« 

•X 

x» 

Active.  Active.         Inactive.         Active.         Inactive. 

Of  such  configurations,  the  following  are  known  : 

7  16 

COOH  COOH 

HO  H  HO  H 

HOH  HOH 

HOH  HOH 

HOH  HOH 

HOH  HOH 

COOH  COOH 

a-Glucopentoxy-  p-Glucopentoxy- 

pimelic  acid.  pimelic  acid. 

Inactive.  Active. 

A  discussion  of  the  methods  and  considerations  leading  to 
the  determination  of  the  positions  O  and  OH  as  they  have  been 
developed  by  E.  Fischer  for  the  bodies  of  the  sugar  group,  does 
not  fall  within  the  plan  of  this  book. 

Asymmetric  Molecules  with  Chain  Structure  which  contain  a 
double  carbon  linkage  must,  in  consequence  of  the  resulting 
cis-trans  isomerism,  show  d-  and  /-modifications  for  each  of  the 
two  forms.  According  to  Walden,1  who  called  attention  to 

1  Walden  :  Ber.  d.  chem.  Ge<v,  27,  3476. 
5 


66  OPTICAL   MODIFICATIONS 

these  relations,   the  following  bodies  may   be  of  this   kind  : 

Right-rotating      1  CHS.(CH,)5.*CH(OH).CH.2.CH 
ricinelaiidic  acid.      > 

Transform.        J  H.C.(CHa)7.COOH 

Right-rotating      )  CHV(CH2)5.*CH(OH).CH2.CH 
ricinoleic  acid.       V 

Cisform.  j  COOH.(CH,)7.C.H 

The  left-rotating  antipodes  are  as  yet  unknown. 

Asymmetric  bodies  having  a  triple  carbon  linkage  can  yield 
only  one  pair  of  optical  antipodes  ;  thus,  from  the  above  acids 
only  a  single  </-ricinstearoleic  acid,  corresponding  to  the 
formula1 

CH3.(CH2)5*CH(OH).CH2.C  j  C.(CHS)7.COOH, 
may  be  obtained. 

Ring  Structure  Molecules. — Those  which  contain  only  one 
asymmetric  carbon  atom  yield  d-,  /-,  and  /--modifications,  as 
has  been  already  shown  for  many  bodies,  such  as  methyl-, 
ethyl-,  and  propylpiperidine,  limonene,  menthene,  camphene, 
pinene,  and  others. 

Cyclic  compounds  with  two  asymmetric  carbon  atoms  may 
exist  in  four  active  isomeric  forms,  two  of  each  being  optical 
antipodes,  and  also  in  two  racemic  forms.  As  a  matter  of  fact, 
these  six  forms  are  known  in  the  case  of  the  camphoric  acids 
of  which  there  exist,  according  to  Aschan,'  only  (i)  the 
common  d-,  /-,  and  r-camphoric  acids  which  correspond  to  the 
maleinoid  or  cis  form,  and  (2)  the  d-,  /-,  and  r-isocamphoric 
acids  which  correspond  to  the  fumaroid  or  cis- trans  form.  As 
i>  well  known,  the  structure  of  camphoric  acid  has  not  been 
finally  settled  ;  the  above  relations  point  to  the  existence  of 
two  asymmetric  carbon  atoms.  (Bredt's  formula  contains 
three,  those  of  Tiemann  and  Semmler  four,  *C.) 

The  same  conditions  appear  to  obtain  with  other  cyclic 
compounds,  as,  for  example,  borneol,  the  composition  of  which 
i^  not  definitely  known. 

Further  details  concerning  the  relations  of  optical  modi- 
fications will  be  found  in  the  chapter  on  the  "Development  of 
Active  Isomers." 

1  Goldsobcl  :  Her.  d.  chem.  Ges.,  37,  3121. 
*  Aschan  :   Ibid.,  37,  2001. 


PHYSICAL   AND   CHEMICAL    BEHAVIOR  67 

B.     Physical  and  Chemical  Behavior  of  the  Optical  Modifications 
a.  BEHAVIOR  OF  THE  ANTIPODES 

17.  Physical  Properties. — Of  these,  only  such  can  be  different 
for  the  two  antipodes  in  which  the  contrast  of  -f  and  —  is 
essentially  inherent.  Besides  optical  right  and  left  rotation,  and 
the  enantiomorphism  of  crystals,  \.\\e  pyroelectricity  of  the  latter 
belongs  here.  The  phenomenon  of  opposite  electrical  poles  in 
a  certain  class  of  crystals  is  disclosed  only  when  they  are 
heated,  or  cooled,  or  subjected  to  one-sided  strain  or  pressure. 
Among  such,  which  in  solid  or  dissolved  condition  show 
optical  activity,  the  following  have  been  found  to  exhibit 
pyroelectricity  : 

Hexagonal  System  :  quartz,  potassium-lithium  sulphate, 
sodium-lithium  sulphate,  potassium  bromate,  potassium  peri- 
odate,  ^-antimonyl-strontium  tartrate,  aMead  tartrate. 

Tetragonal  System  :  ^-antimonyl-barium  tartrate. 

Monoclinic  System  :  d-  and  /-tartaric  acid,  ^-potassium, 
ammonium  and  strontium  tartrates,  cane-sugar,  milk-sugar, 
d-  and  /-carvoxime,  d-  and  /-fenchone  oxime,  d-  and  l-a- 
carvone  pentabromide. 

For  further  information  on  the  subject  of  pyroelectricity  of 
crystals,  the  reader  is  referred  to  the  excellent  discussion  of 
this  condition  in  Liebisch's  <f  Grundriss  der  physikalischen 
Krystallographie,"  1896.  pp.  462  to  471. 

All  other  physical  properties,  on  the  contrary,  are  perfectly 
identical  in  the  antipodes.  As  observations  on  numerous 
substances  have  shown,  this  is  the  case  with  respect  to 

1 .  Specific  gravity. 

2.  Melting-point  and  boiling-point. 

3.  Solubility.1 

4.  Heat  of  solution   (d-    and  /-tartaric   acid,  Berthelot    and 

Jungfleisch  f  d-  and  /-inositol,  Berthelot).3 

1  Certain  statements  are  found  concerning  the  unequal  solubility  of  antipodes.  At 
ordinary  temperature  rf-asparagine  is  said  to  be  somewhat  more  soluble  than 
/-asparagine.  (Piutti  :  Ber.  d.chem.  Ges..  19,  1692.)  In  cooling  down  a  hot  aqueous 
solution  of  racemic  camphoric  acid,  Jungfleisch  observed,  first  the  separation  of  the 
left-rotating,  and  then,  below  40°,  of  right-rotating  crystals.  In  dilute  acetic  acid  the 
solubilities  were  even  more  different  (Bull.  Soc.  Chim.,  [2],  41,  224).  It  is  a  question,  in 
such  cases,  whether  real  antipodes  were  present  or  not. 

-  Berthelot  and  Jungfleisch  :  Compt.  rend.,  78,  711. 

•'*  Berthelot:  Ibid.,  no,  1244. 


68  OPTICAL   MODIFICATIONS 

5.  Heat  of  combustion   (close  agreement  found  for  d-  and 

/-camphoric  acid,  Louguinine  -,l  d-  and  /-mannonic  acid 
lactone,  Fogh).1 

6.  Heat    of    neutralization   (shown    for    d-    and   /-tartaric 

acid  with  active  bases,  Jahn).2 

7.  Electrical     conductivity     (d-  and    /-tartaric   acid,    Ost- 

wald).3 

8.  Index  of  refraction   (shown  for  d-  and    /-terpenes   and 

derivatives,  Wallach,  Briihl). 

18.  Different  Behavior  of  the  Antipodes  on  Combination  with  Active 
Substances.  Conditions  of  Solubility. — If  the  d-  and  /-forms  of  an 
active  body  be  brought  into  new  combinations  which  contain 
the  original  active  complex,  and  in  which  no  new  asymmetric 
carbon  atom  is  added,  the  two  products  are  perfectly  identical, 
with  exception,  of  course,  of  their  opposite  rotating  powers 
and  crystalline  enantiomorphism.  This  is  the  case  when  the 
antipodes  of  an  acid  are  combined  with  an  inorganic,  or  with 
an  inactive  organic  base  ;  the  two  salts  show  the  same  solu- 
bility, contain  the  same  amount  of  water  of  crystallization,  and 
so  on. 

However,  if  the  two  oppositely  rotating  forms  be  brought 
into  combination  with  an  active  substance,  so  that  new  asym- 
metric carbon  atoms  are  added,  then  marked  differences  in 
behavior  may  appear.  This  is  the  case  when  a  d-  and  /-acid 
are  combined  with  the  same  alkaloid,  or  a  d-  and  /-base  with 
the  same  active  acid;  for  example,  with  df- tartaric  acid  ;  the 
two  salts  differ,  especially  in  their  solubilities.  The  reason  for 
this  is  found  simply  in  the  fact,  that  when  a  right  and  left 

asymmetric  group, 

b  b 

_'_  _L 

i  r 

are  attached  to  the  same  asymmetric  complex, 


d-C-f 


I 
e 

the  two  resulting  bodies 

1  lyouguinine,  Fogh.  see  Stohmann  :  Ztschr.  phys.  Chem.,  6,  334,  and  10,  410. 

»  H.  Jahn  :  Wied.  Ann.,  43,  306. 

*  Ostwald  :  Ztschr.  phys.  Chem.,  3,  371. 


DIFFERENT    BEHAVIOR    OF   THE    ANTIPODES  69 

b  b 

I  i 

a— C— c  c— C— a 

d— C— f  d— C— f 

I  1 

e  e 

are  no  longer  mirror  images  of  each  other. 

The  unequal  solubility  of  two  such  isomeric  combinations 
does  not  appear  to  bear  any  definite  relation  to  the  direction 
of  rotation  of  the  active  components.  When  the  same  alkaloid 
is  united  to  different  active  acids,  sometimes  the  d-form  of  the 
latter,  and  sometimes  the  /-form,  gives  the  least  soluble  salt; 
that  is,  the  one  which  precipitates  first.  In  the  same  manner 
df-tartaric  acid  behaves  differently  with  the  antipodes  of  differ- 
ent bases.  This  is  shown  by  the  following  observations  which 
in  the  main  have  been  taken  from  a  table  by  Winther.1  The 
symbols  (  W}  and  (A)  indicate  the  solvent,  water  or  alcohol : 

^/-Cinchonicine  precipitates   /-tartaric  acid  (  W)]2 

^-Cinchonine  "           /-tartaric  acid  (  W}? 

d-          "  /-cinnamic  acid  dibromide  (A),* 

d-  ^-methoxysuccinic  acid  (  W}? 

d-  "          tf-mandelic  acid  (  IV),6 

d-          "  rf-isopropyl phenylgly colic  acid  (A], 7 

d-  df-phenyl-a-bromlactic  acid  (A)  ;8 

^-Qumidine  "          ^-cinnamic  acid  dibromide  (A]  f 

</-Quinicme  rf-tartaric  acid  (  W]  ;10 

/-Quinine  "          <f-tartaric  acid  (  JF),11 

/-  ^-tropic  acid  (fF),12 

/-  /-isopropylphenylglycolic  acid  (A)  ;13 

/-Cinchonidine  ^/-ethoxysuccinic  acid  (  W),u 

Winther :  Ber.  d.  chem.  Ges.,  28,  3020. 
Pasteur:  Cotnpt.  rend.,  37,  162. 
Pasteur  :  Ann.  chim.  phys.,  [3]  38,  437. 

Erlenmeyer,  Jr.  :  Ann.   Chem.    (Liebig),  271,  159;  Ber.  d.  chem.  Ges.,  26,  1659; 
I^iebermann  :  Ibid.,  26,  1663  ;  Hirsch  :  Ibid.,  27,  883. 
Purdie  and  Marshall  :  J.  Chem.  Soc.,  63,  217. 
I^ewkowitsch  :  Ber.  d.  chem.  Ges.,  16,  1574  and  2721. 
'  Fileti :  Gazz.  chim.  ital.,  22,  [2],  395  ;  J.  prakt.  Chem.,  [2],  46,  560. 

8  Erlenmeyer,  Jr.  :  Ann.   Chem.    (I^iebig),   271,  159  ;  Ber.  d.  chem.  Ges.,  24,  2830; 
26,  1659. 

9  Hirsch  :  Ber.  d.  chem.  Ges.,  27,  883. 
10  Pasteur :  Cotnpt.  Rend.,  37,  162. 

11  Pasteur  :  Ann.  chim.  phys.,  [3],  38,  437. 

:2  I^adenburg  and  Hundt  :  Ber.  d.  chem.  Ges.,  22,  2590. 

15  Fileti :  Loc  cit. 

14  Purdie  and  Walker  :  J.  Chem.  Soc.,  63,  229. 


OPTICAL   MODIFICATIONS 


/-Cinchonidine  precipitates  /-cinnamic  acid  dibromide  (benzene),1 
/-          "  "  /-allocinnamic  acid  dibromide  (benzene)  ;2 

/-Strychnine  "          rf-pyrotartaric  acid  ( W}* 

I-  "  tf-galactonic  acid  (  H7),4 

/-          "  "  </-dihydro-o-phthalic  acid  (  W7),5 

/-          "  d-cinnamic  acid  dichloride  (^),6 

/-          "  rf-cinnamic  acid  dibromide  (A}? 

/-          "  /-lactic  acid  (W7),8 

/-  /-methoxysuccinic  acid  (  W7),9 

/-          "  /-propoxysuccinic  acid  ( W)  ;10 

/-Brucine  *f-tartaric  acid  (A},u 

I-  •'  </-a-oxybutyric  acid  (  W7;,12 

/-  "  ^-a-p-cinnamic  acid  dibromide 

/-  "  rf-phenyl-p-7-dibrombutyric  acid 

/-  "  /-valerianic  acid  (  W}  ;15 

d-Tartaric  acid  </-a-pipecoline  (  W7),16 

d-  "  */-ethylpiperidine  ( JF),17 

rf-  "  ^/-conine  (  W7),18 

^/-  "  "                "          ^/-copellidine  ( Jf7),19 

d-  "  </-tetrahydroquinaldine  (  W)™ 

d-  "  "                            /-/a-pipecoline  (  K7),21 

rf-  "  /-isocopellidine  (  W}™ 

d-  "  /-propylenediamine  (  W7),  23 

</-  "  -/-i,5-tetrahydronaphthylenediamine(  Jf7).24 

1  Hirsch  :  Zx?c  c»A 

2  Liebermann  :  Ber.  d.  chem.  Ges.,  27,  2042. 

3  I^adenburg  :  Ibid.,  28,  1170. 

4  Fischer  and  Hertz  :  Ibid.,  25,  1257. 

5  Proost  :  Ibid.,  27,  3185. 

•  Liebennann  and  Finkenbeiner  :   Ibid.,  26,  883 ;  Finkenbeiner  :  Ibid.,  27,  889. 
'  Loth.  Meyer,  Jr.  :  Ibid.,  25,  3121  ;  Liebermann  :  Ibid.,  26,  245  ;  Liebermann   and 
Hartmann  :  Ibid.,  26,  829  and  1665. 

•  Purdie  and  Walker  :  J.  Chem.  Soc.,  61,  754. 

*  Purdie  and  Bolam  :  Ibid.,  67,   944. 
'"  Ibid. 

11  Pasteur:  Ann.chim.  phys.,  [3],  loc.  cit. 

12  Guye  and  Jordan  :  Compt.  rend.,  120,  562. 
Hirsch:  Loc  cit. 

H  Loth.  Meyer,  Jr.,  and  Stein  :  Ber.  d.  chem.  Ges.,  27,  890. 

"  Schiitz  and  Marckwald  :  Ibid.,  29,  52. 

16  Ladenburg  :  Ann.  Chem.  (Liebig),  247,  64. 

»•  Ibid.,  p.  71. 

18  Ibid.,  p.  85. 

19  Levy  and  Wolffenstein  :  Ber.  d.  chem.  Ges.,  28,  2270. 
10  Ladenburg  :  Ibid.,  27,  76. 

«  Ibid.,  p.  75. 

M  Levy  and  Wolffenstein  :  Loc.  cit. 

»  Baumann  :  Ber.  d.  chem.  Ges.,  28,  1179. 

54  Bamberger  :  Ibid.,  23,  291. 


PHYSIOLOGICAL  DIFFERENCES  71 

In  the  above  list  there  are  nineteen  cases  in  which  bases  and 
acids  of  opposite  rotation  unite  to  form  a  less  soluble  salt,  and 
seventeen  cases  in  which  the  salt  is  formed  by  the  union  of 
acids  and  bases  of  like  rotation. 

In  the  two  groups  of  isomeric  cinchona  alkaloids  their  com- 
position appears  to  play  some  part  as  may  be  seen  from  the 
following  table  in  which  is  given  the  modifications  of  several 
acids  which  yield  the  less  soluble  salts  writh  the  bases: 


—  «*a 

Bases  Co0H24N2Oo. 

Cin- 
chonine. 

Cincho- 
nicine. 

Cincho- 
nidine. 

Quini- 
cine. 

^  JQ— 

I 

I 

d 
d 

/ 
d 

d 

d 
d 
I 

Phenyldibrompropi- 

Isopropylphenylgly- 
colic  acid  

— 

Methoxysuccinic 

From  this  it  might  appear  that  the  bases  of  each  group 
behave  in  a  similar  manner  with  each  acid  and  also  that  the 
two  groups  are  opposed  to  each  other  in  their  action;  if  the 
one  combines  with  the  d-form  of  an  acid  the  other  takes  the 
/-form.  Howrever,  a  greater  number  of  observations  w7ill  be 
required  to  fully  establish  the  rule. 

Ch.  Winther  has  proposed  a  theory  concerning  the  resolu- 
tion of  racemic  bodies  by  active  bases  wThich  takes  into  con- 
sideration the  configuration  of  the  molecules.1  Reference  only 
can  be  made  to  this  here. 

For  the  application  of  the  unequal  solubilities  of  the  salts  of 
active  bases  and  acids  in  splitting  racemic  bodies,  see  §  33. 

19.  Physiol  ical  Differences  between  the  Antipodes. — These  are 
recognized  through  the  following  phenomena: 

i.  By  the  power  which  certain  organized  ferments  possess, 
when  growing  in  solutions  of  racemic  bodies,  to  destroy  one  com- 
ponent of  the  combination  while  the  other  is  left  unchanged. 

This  power  belongs  especially  to  a  number  of  molds,  such  as 

1  Ch.  Winther:  Ber.  d.  chem.  Ges.,  28,  3000. 


72  OPTICAL   MODIFICATIONS 

Penidllium  glaucum,  Mucor  Mucedo,  Aspergillus  fumigatus, 
and  others,  also  to  several  kinds  of  yeast,  and  finally  to  certain 
schizomycetes  (Bacterium  termo,  Bacillus  ethaceticus  and 
others) .  The  first  observations  on  this  point  were  made  by 
Pasteur1  in  1860,  who  found  that  if  spores  of  Penidllium 
glaucum  along  with  traces  of  nutritive  salts  (potassium  phos- 
phate and  magnesium  sulphate)  are  sown  in  a  solution  of 
ammonium  racemate,  the  originally  inactive  liquid  becomes 
gradually  levorotatory  as  the  development  of  the  fungus  pro- 
ceeds and  that  finally  no  dextrotartaric  acid  whatever  is  left. 
It  was  observed  later  that  solutions  of  many  other  racemic 
bodies  in  contact  with  fungi  behave  in  the  same  manner,  and 
consequently  that  from  them  in  some  cases  the  right-rotating 
and  in  other  cases  the  left-rotating  form  could  be  secured.  In 
this  way  it  was  found  possible  to  obtain  active  forms  from  a 
number  of  racemic  acids,  as  lactic  acid,  aspartic  acid,  mandelic 
acid,  and  even  from  haloid  acids,  for  example  from  cinnamic 
acid  dichloride,  also  from  several  alcohols,  as  methylethyl- 
carbinol,  methylpropylcarbinol,  propyleneglycol,  and  others 
(see  §  34).  With  many  substances,  however,  the  growth  of 
fungi  is  not  possible  and  they  remain  in  the  inactive  condition. 
Further  data  concerning  the  methods  employed  in  such 
experiments,  and  a  description  of  the  fungi,  will  be  found  in  § 

34- 

In  the  following  the  question  of  the  mode  of  action  of  the 
fungi,  and  whether  any  definite  rules  may  be  deduced,  will  be 
taken  up  first.  It  must  be  remarked  at  the  outset,  however, 
concerning  observations  in  this  direction,  that  many  of  them 
date  from  a  time  when  methods  of  producing  pure  cultures 
of  the  fungi  had  been  but  little  developed  and  that  without 
doubt  many  experiments  were  carried  out  with  impure  material. 
The  results,  therefore,  can  not  be  looked  upon  as  fully  estab- 
lished in  all  cases. 

As  far  as  the  molds  are  concerned,  it  does  not  appear  that 
different  varieties  possess  any  definite  selective  action  on  the 
antipodes.  It  has  been  found  on  the  contrary  that  the  same 
mold  decomposes  the  ri^lit  modification  of  some  racemic  bodies, 
and  the  left  modification  of  others.  For  example,  by  the  aid 

1  Pasteur:  Cotnpt.  rend.,  51,  298. 


PHYSIOLOGICAL   DIFFERENCES  73 

of  Penicillium   glaucum,    the    following    active    forms    were 
obtained  from  racemic  bodies  i1 

</-methylethylcarbin  carbinol, 
rf-ethylidene  lactic  acid, 
df-ethoxysuccinic  acid, 
*/-mandelic  acid, 
</-aspartic  acid,2 
rf-leucine,3 

/•methylethylcarbinol, 

/-methylpropylcarbinol, 

/-ethylpropyl  carbinol , 

/-tartaric  acid, 

/-mannonic  acid  lactone, 

/-glutaminic  acid,4 

/-glyceric  acid. 

As  seen,  the  destructive  action  of  the  fungus  on  the  alcohols, 
as  well  as  on  the  acids,  is  exerted  in  some  instances  on  the  one 
form,  and  in  others  on  the  opposite. 

There  are  some  cases  in  which  from  racemic  bodies,  the 
dextro  form  may  be  obtained  by  one  variety  of  fungus  and  the 
levo  form  by  aid  of  a  different  fungus.  Thus,  there  are  not 
attacked  : 

o'-Mandelic   acid   by   Penicillium  glaucum,  Mucor  Mucedo. 
I-        "  "      "     Saccharomyces  ellipsoideus  and   another 

schizomycite  not  definitely  known  (vibrio5). 
d-G\y eerie  acid6      "     bacillus  ethaceticus ." 
I-        "  "     Penicillium  glaucum* 

^-Tartaric      "         "     a  certain  unnamed  schizomycite  (vibrio9). 
/-         "          "         "     Penicillium  glaucum™ 

The  investigations  of  E.  Fischer  have  thrown  much  light 
on  the  action  of  yeasts  (Saccharomyces  ellipso'ideus,  S. 
cerevisiae,  S.  Pastorianus,  S.  Marxianus,  etc.)  on  the 

1  The  literature  of  these  data  will  be  found  in  §  34. 

2  The  hydrochloric  acid  solution  of  the   /-form,  which  in  water  shows  dextro- 
rotation,  was  not  attacked. 

3  The  form  rotating  to  the   left  in  hydrochloric  acid,  and  in  water  to  the  right, 
was  obtained. 

4  The  form  rotating  to  the  left  in  hydrochloric,  and  in  the  same  direction  when 
dissolved  in  water,  was  left. 

5  Ivewkowitsch  :  Ber.  d.  chem.  Ges.,  15,  1505;  16,  1568. 

6  The  racemic  calcium  glycerate  used,  left  the  levorotating  salt  which  corresponds 
to  the  dextro  acid. 

~  Frankland  and  Frew  :  J.  Chem.  Soc.,  59,  101. 
*  l,ewkowitsch  :  Ber.  d.  chem.  Ges.,  16,  2720. 

9  Lewkowitsch  :  Loc .  cit. 

10  Pasteur,  LeBel. 


74  OPTICAL   MODIFICATIONS 

different  kinds  of  sugars.  It  was  found,  that  of  the  two 
antipodes,  only  one  undergoes  fermentation,  while  the  other 
remains  unchanged.  Thus  : 

Ferment.  Do  not  ferment. 

d  (-r)  Glucose,  /(  — )  Glucose,1 

d  (-f)  Mannose,  /  (— )  Mannose,2 

d  (  +  )  Galactose,  /  (— )  Galactose,3 

d  (— )  Fructose,  /(  +  )  Fructose.* 

Again,  it  was  found  that  writh  isomeric  sugars  which  show 
the  same  direction  of  rotation  the  configuration  of  the  mole- 
cule exerts  an  influence  on  the  behavior  toward  yeast.  Fischer 
and  Thierf elder5  have  found  the  following  differences: 


Easily  fermentable. 

Difficulty 
fermentable. 

Not 
fermentable. 

d-Glucose. 

rf-Mannose. 

d-Galactose. 

rf-Talose. 

CH2OH 

CH2OH 

CH2OH 

CH2OH 

HO—  C—  H 

HO—  C—  H 

HO—  C—  H 

HO—  C—  H 

HO—  C—  H 

HO—  C—  H 

H—  C—  OH 

H—  C—  OH 

I 

I 

H—  C—  OH 

H—  C—  OH 

H—  C—  OH 

H—  C—  OH 

HO—  C—  H 

1 
H—  C—  OH 

HO—  C—  H 

H—  C—  OH 

1 

I 

I 

1 

CHO 

CHO 

CHO 

CHO 

2.  Unorganized  Ferments  {Enzymes)  show  in  their  power 
of  splitting  glucosides  phenomena  similar  to  those  of  the 
yeasts.  Investigations  of  E.  Fischer  have  shown  that  the 
hydrolysis  of  the  a-  and  /7-isomeric  forms  (different  configura- 
tions) of  d-  and  /-methyl  glucoside  may  depend  on  (i)  the 
nature  of  the  enzyme,  (2)  the  configuration  of  the  glucoside, 
and  (3)  the  direction  of  rotation  of  the  active  group.  The  fol- 
lowing relations  have  been  observed:6 

Emulsin.  Invertin. 

o-Methyl,  rf-glucoside does  not  split  splits 

o-      "          /-         "         does  not  split  does  not  split 

ft-      "         d-        "         splits  does  not  split 

ft-      "          /-         "         does  not  split 

'her  :  Ber.  d.  chem.  Ges.,  33,  2621;  37,  2031. 
Fischer  :  Ibid.,  33,  382. 
Fischer  :  Ibid..  35,  1259. 
ischer  :  Ibid.,  33,  389. 
Fischer  and  Thierfelder:  Ibid.,  37,  2035. 
Fischer-  Ibid.,  37,  2985;  38,  1429. 


PHYSIOLOGICAL   DIFFERENCES  75 

Finally,  as  regards  the  explanation  of  the  behavior  of  the 
pure  enzymes,  as  well  as  of  that  of  the  fungi  containing 
enzymes,  there  can  be  but  little  doubt  that  here  the  same  con- 
ditions obtain  as  in  the  case  of  bringing  together  racemic  acids 
and  alkaloids.  The  enzymes,  like  all  other  albuminous  bodies, 
represent  asymmetric  molecules  endowed  with  rotating  power, 
and  therefore  behave  differently  with  the  optical  antipodes. 
Pasteur,1  many  years  ago,  employed  an  illustration  when  he 
remarked  that  if  a  right  and  left  screw  be  driven  into  pieces  of 
wood,  the  fibers  of  which  run  in  a  straight  direction  (inactive 
substance ) ,  two  systems  of  the  same  kind  are  produced  ;  but 
that  this  is  no  longer  the  case  if  the  fibers  of  the  wood  them- 
selves possess  a  spiral  form,  and  turned  in  opposite  directions 
in  the  two  pieces.  Again,  as  regards  the  unequal  action  of 
molecules  of  different  configurations,  it  appears  that  the  yeast 
cells  with  their  asymmetrically  formed  active  agent  attack  and 
ferment  only  those  kinds  of  sugars  whose  geometry  is  not  too 
greatly  different  from  that  of  grape-sugar  (Fischer  and 
Thierf elder2.)  In  the  same  way,  one  can  represent  the  action 
of  the  enzymes  on  glucosides  as  taking  place,  only  when  the 
geometric  forms  are  such  as  to  permit  that  close  approach  of 
the  molecules  necessary  to  the  beginnings  of  chemical  change. 
To  employ  a  figure  used  by  Fischer,3  the  two  bodies  must  fit 
each  other  as  lock  and  key.  What  becomes  of  the  part  of  the 
active  substance  taken  up  by  the  organized  ferment,  is  known 
only  in  the  case  of  a  few  fermentations  ;  for  all  other  cases 
there  are  no  available  obse rvations. 

3.  Farther  physiological  differences  between  optical  anti- 
podes have  been  observed  in  a  few  instances  with  reference  to 
toxicity  and  taste. 

Different  Degrees  of  Toxicity  between  d-  and  I-  Tartaric  Acid 
were  noted  by  Chabrie4  by  injecting  solutions  of  i  part  of  acid 
to  5  or  6  parts  of  water  into  the  peritoneal  cavity  of  guinea 
pigs  and  observing  the  time  required  to  produce  death.  From 
the  experiments  which  were  extended  to  include  racemic  and 
mesotartaric  acids,  inactive  modifications,  it  was  found  that  the 

1  Pasteur:  "  Dissymmetric  moleculaire,"  1860. 

-  Fischer  and  Thierfelder  :  Ber.  d.  chem.  Ges.,  27,  2036. 

:{  Fischer  :  Ibid.,  27,  2992. 

4  Compt.  rend.,  116,  1410. 


76  OPTICAL    MODIFICATIONS 

toxicity  of  the  different  acids  calculated  Tor  equal  weights  of 
animal  were  as  follows: 

Left  tartaric  acid 31 

Right  tartaric  acid 14 

Racemic  acid 8 

Mesotartaric  acid 6 

According  to  this,  /-tartaric  acid  is  about  twice  as  strong  a 
poison  as  the  d-acid. 

With  conine,  Ladenburg1  noticed  no  difference  in  toxicity 
between  the  natural  right-rotating  base  and  the  synthetic 
racemic  o'-propylpiperidine. 

A  difference  in  taste  between  d-  and  /-asparagine  has  been 
noted.  In  evaporating  an  aqueous  solution  of  20  kilograms 
of  asparagine  obtained  from  vetch  shoots,  Piutti2  noticed  the 
formation  of  enantiomorphous  crystals,  which,  when  separated 
from  each  other  mechanically,  were  found  to  be  characterized 
by  equal  and  opposite  rotations,  and  further  by  the  fact  that 
the  right-rotating  crystals  had  a  sweet  taste,  while  those 
rotating  to  the  left  had  the  very  slight  taste  of  the  common 
asparagine.  In  derivatives  from  the  two  forms,  such  as  d-  and 
/-aspartic  acid  a  difference  in  taste  was  no  longer  noticed. 
The  equal  rotations  of  the  two  forms  indicate  that  the  two 
asparagines  are  real  optical  antipodes.  A  second  example  is 
given  by  glutaminic  acid,  the  d-form  of  which  has  a  specific 
taste  while  the  /-form  is  tasteless.3  Pasteur4  has  made  the 
suggestion  that  the  differences  in  taste  may  be  due  to  the 
nerves  themselves  being  formed  of  asymmetric  substances, 
and  that  an  effect  exists  here  like  that  of  the  ferments. 

b.  PROPERTIES  OF  RACEMIC  COMPOUNDS  AND  DISTINCTIONS 
BETWEEN  THESE  AND  ACTIVE  MODIFICATIONS. 

The  inactive  racemic  bodies  obtained  in  various  ways  (see  § 
27  to  33)  may  be  in  part  definite  chemical  compounds  (symbol 
r)  or  mechanical  mixtures  of  the  active  antipodes  (symbol  dl)? 
In  both  cases  they  may  be  split  up  into  the  latter. 

As  definitely  characterizing  racemic  compounds  the  follow- 

1  Ladenburg:  Ann.  Chem.  (Liebig),  347,  83. 

2  Piutti:  Ber.  d.  chem.  Ges.,  19,  1691;  Gazz.  chim.  ital.,  17,  126,  182. 
8  Menozzi  and  Appiani:  Ace.  d.  L,incei,  1893,  II,  421. 

4  Pasteur:  Compt.  rend.,  103,  138. 

*  Following  the  suggestion  of  E.  Fischer:  Ber.  d.  chem.  Ges.,  28,  1153. 


MOLECULAR    WEIGHT  77 

ing  relations  may  be  taken  into  consideration,  which  show, 
first,  the  differences  between  them  and  the  active  modifications, 
and  which,  secondly,  permit  in  given  cases  a  determination  of 
the  question  as  to  which  is  present,  a  compound  or  mixture  of 
the  antipodes. 

i.     Crystallized  Racemic  Compounds 

20.  Molecular  Weight. — It  was  attempted  to  show  by  cryo- 
scopic  methods  that  racemic  bodies  have  twice  the  molecular 
weight  of  the  antipodes,  but  without  success.  It  was  found 
that  equally  strong  solutions  of  active  and  inactive  forms 
always  cause  the  same  depression  of  the  freezing-point,  and 
therefore  that  the  racemic  forms  in  solutions  separate  into 
their  components.  This  was  observed  first  by  Raoult1  with 
racemic  and  tartaric  acids  (under  5  parts  to  100  of  water),  also 
with  their  sodium-ammonium  salts,  and  later  in  still  other 
cases,  as  with  the  dimethyl  esters  of  diacetyl  racemic  acid, 
diacetyl  tartaric  acid,2  isonitrosodipentene  and  isonitroso- 
limonene  dissolved  in  glacial  acetic  acid.3  The  identity  of 
equally  diluted  solutions  of  racemic  acid  with  d-  and  /-tartaric 
acid  was  found  further  in  the  agreement  of  the  specific  gravi- 
ties,* the  electrical  conductivity,5  and  magnetic  rotation.6 

The  determination  of  vapor-density  proved  of  equally 
little  value.  Anschiitz7  found  that  diethyl  racemate  and 
*/-tartrate  have  the  same  vapor-density,  and  consequently  that 
the  first  substance,  in  case  it  exists  as  a  racemic  compound  in 
liquid  form,  must  have  broken  down  into  the  two  tartrate 
esters.  With  the  solid  dimethyl  racemate,  whose  melting- 
point  (85°)  is  markedly  different  from  that  of  the  tartrate 
ester  (45°),  the  decomposition  appears  to  take  place  at  the 
boiling  temperature  (158°  at  11.5  mm.),  because  this  is  the 
same  for  the  two  bodies. 

In  view  of  the  fact  that  the  densities  of  diethyl  racemate 
and  tartrate  in  liquid  condition  are  the  same,  I.  Traube8 

i  Raoult:  Ztschr.  phys.  Chem.,  i,  186. 

-  Pulfrich:  See  Anschiitz:  Ann.  Chem.  (I^iebig),  247,  121. 

3  Wallach:/£z<f.,  246,  231. 

4  Perkin:  J.  Chem.  Soc.,  52,  362;  Marchlewski:  Ber.  d.  chem.  Ges.,  25,  1556. 

5  Ostwald:  Ztschr.  phys.  Chem.,  3.  371. 

6  Perkin:  Loc.cit. 

'  Anschiitz  :  Ber.  d.  chem.  Ges.,  18,  1397. 
8  I.  Traube  :  Ibid.,  29,  1394. 


78  OPTICAL   MODIFICATIONS 

comes  to  the  conclusion,  aided  by  the  atomic  constants  pro- 
posed by  him,1  that  the  molecules  of  all  three  bodies  are  simple, 
and  therefore,  that  the  liquid  ethyl  racemate  is  a  mixture  of 
the  two  tartrate  esters. 

In  the  same  way,  Traube  draws  the  conclusion  from  the 
densities  of  the  crystalline  racemic  acid  and  tartaric  acid,  that 
both  bodies  have  the  same  molecular  weight,  which  cor- 
responds to  the  formula  (C4H6O6)2.  This  reaction  of  changing 
solid  racemic  acid  or  its  salts  into  the  mixture  of  tartrates 
(see  §27)  would  not,  therefore,  be  represented  by  d  -f-  /=  dl, 
but  by  dd  -f  //  =  zdl. 

21.  Crystalline  Form  and  Water  of  Crystallization. — In  the  union 
of  enantiomorphous  antipodes  to  form  a  racemic  compound, 
the  following  cases  may  appear  : 

1 .  A  body  of  different  composition  may  be  formed  by  the 
loss  or  addition    of    water  of    crystallization.     A  change  in 
crystalline  form  naturally  results  with  this.2 

For  example  : 

Tartaric  and  racemic  acid.  Crystalline  form. 

Active,  C4H6OB monoclinic-hemimorphous. 

Racemic,    C4H6O6  -f-  H2O triclinic-holohedral. 

Sodium-ammonium  tartrate  and  racemate.  Crystalline  form. 

Active,  NaNH4C4H4O6  -f  4H2O rhombic-hemihedral. 

Racemic,  NaNH4C4H4O6  +  H2O monoclinic-holohedral. 

2.  The  composition  may   remain  unchanged.     Even   then, 
as   observation  has  shown,   the  crystals  of  the  racemic  com- 
pound belong  to  a  crystalline  group  different  from  that  of  the 
active  forms.     For  example: 

Sodium  tartrate  and  racemate.  Crystalline  form. 

Active,  Na.JC4H4O6  -f  2H2O rhombic-heinihedral 

Racemic,  Na,C4H4Oti       2H,O monoclinic-holohedral. 

Carvonetetrabromide.  Crystalline  form. 

Active,  C,0H,4Br4O rhombic-hemihedral. 

Racemic,  C10H,4Br4O monoclinic-holohedral. 

It  appears  that  in  some  unusual  cases  the  crystalline  system 
may  remain  unchanged,  the  group  only  being  altered.  For 
example: 

1  Traube  :  Ber.  d.  chem.  Ges.,  a8,  2724,  2728,  2924  ;  39,  1023. 

2  These  data  are  from  Rammelsberg's  "  Handbuch  clcr  kry*t.  and  phys.  Chemie,1' 
Vol.  II  (1882),  and  from  lyiebisch's  "  Grundriss  dei  phyv  Kiyst."  (1896). 


DENSITY  79 

Potassium  antimonyl  tartrate  and  racemate.  Crystalline  form. 

Active,  KSbOC4H4O6  +  £  H2O rhombic-hemihedral. 

Racemic,  KSbOC4H4O6  —  \  H2O rhombic-holohedral. 

While  the  active  antipodes  belong  always  to  one  of  the  1 1 
crystalline  groups  described  in  §  5  the  racemic  forms  are 
always  found  in  one  of  the  21  of  the  32  possible  groups 
in  which  hemihedral  forms  are  excluded.  In  these  differences 
we  have  the  most  decided  characteristics  of  true  racemic  com- 
pounds. 

The  amount  of  water  of  crystallization  in  racemic  forms 
may  be  the  same  or  greater  or  less  than  in  the  active  forms. 
In  these  relations  there  is  no  fixed  rule.  We  have,  for 
illustration: 

Racem.      Active. 

Tartaric  and  racemic  acid,                          C4H6O6  H2O 

Ammon.  tartrate  and  racemate,                 (XH4)2  C4H4O6  —  2H2O 

Potass,  tartrate  and  racemate,                   K>C4H4O6  —  2H2O   iH2O 

Sodium  tartrate  and  racemate,                   Xa,C4H4O6  —  2H.,O    2H2O 

Thallium  tartrate  and  racemate,                T1,C4H4O6  -JH2O 

Sod. -ammon.  tartrate  and  racemate,        Xa  XH4)C4H4O6  -f  H.,O    4H4O 

Potass,  lithium  tartrate  and  racemate,     KLiC4H4OH  —  H.,O      H,,O 

Potass,  antimon.  tartrate  and  racemate,  KSbOC4H4O6  -  |H2O    2H2O 

Calcium  mannonate,                                     Ca(C6HHO7)2  -    2H.2O1 

Strontium  glycerate,                                     Sr(C3H-<  —  iH,O  3H..O'- 

Barium  glycerate,                                          Ba(C3H5O4),  }H,O  3H,O- 

22.  Density. — The  specific  gravities  of  the  active  isomers  and 
of  the  racemic  form  of  a  number  of  crystalline  bodies  have 
been  determined  by  Liebisch3  and  by  Walden.4  The  observa- 
tions have  shown  that  the  densities  for  the  d-  and  /-modifica- 
tions, which  were  always  found  to  be  the  same,  were  in  most 
instances  smaller  than  that  for  the  corresponding  racemic  form. 
In  some  cases  the  reverse  was  found  to  be  true,  while  perfect 
agreement  may  also  occur.  In  the  following  table,  which  pre- 
sents these  three  cases,  the  amount  of  increase  or  decrease  in 
passing  from  the  active  to  the  racemic  form  is  given.  The 
observations  by  Walden  give  values  of  d™\ 

1  Fischer:  Ber.  d.  chem.  Ges.,  23, 

-  Frankland  and  Appleyard:  J.  Chem.  Soc.,  63,  310.     The  i,i,  Mg,  Ca,  Zu  and  Cd 
salts  of  active  and  racemic  glyceric  acid  have  the  same  water  of  crystallization. 
s  I^iebisch  (see  Wallach):  Ann.  Chem.  (tiebig).  286,  139. 
4  Walden:  Ber.  d.  chem.  Ges.,  29,  1692. 


8o 


OPTICAL   MODIFICATIONS 


Active 

forms. 

Ra- 
cemic 
form. 

Change 
in  per 
cent. 

Ob- 
server. 

•759 
•755 
•595 
.188 

.243 
2.134 
1.108 
1.117 
i-i34 
2.2428 
1.128 

1.788 
1.778 
1.601 
1.228 
1.249 
2.225 
1.126 
1.142 
1.180 
2.2495 
1.131 

+  i.7 
+  1-3 
+  0.4 
+  3-4 
+  0.5 
+  4-3 
+  1.6 

+  2.2 

+  4-1 
+  0.3 
+  0.3 

L. 

W.  P.1 
W. 
W. 
W. 
L. 
L. 
L. 
L. 
L. 
L. 

1.687 
2.093 
1.538 
i.34i 

1.679 
2.073 

1.511 
1.300 

-0.5 
—  i.o 
-1.8 
-3-i 

W. 
W. 
W. 
W. 

Carvone  tribromidc  from  hydrocarvonc*  

1.958 

1.958 

0 

L. 

In  those  cases  in  which  the  specific  gravity  of  the  racemic 
bodies  is  greater  or  less  than  those  of  the  components,  it  may 
be  safely  assumed  that  the  first  represent  true  chemical  com- 
pounds. If  they  were  merely  mechanical  aggregations,  the 
same  behavior  should  be  expected  as  with  isomorphous 
mixtures,  the  densities  of  which,  as  is  well  known,  are 
additive  properties,  that  is,  as  the  densities  of  the  isomers  are 
the  same,  that  of  the  raceme  body  should  also  be  the  same.  A 
contraction  or  dilatation,  on  the  contrary,  points  to  chemical 
combination. 

23.  Solubility. — As  far  as  observations  have  shown  the  racemic 
compounds,  as  a  rule,  are  less  readily  soluble  than  the  active 
forms.  Numerical  results  have  been  given  for  the  following 
substances: 

»  Perkin  :  J.  Chem.  Soc.,  51 ,  366. 


SOLUBILITY 
100  Parts  of  solvent  dissolve  at  tc. 


8l 


/• 

Active 
forms. 

Racemic 
form. 

Observer. 

Tartaric  acid 
and 
anhydrous  racenric 
acid  in  water. 

0° 
20 
40 
60 
80 
100 

115.0  pts. 

139.4    " 
176.0    " 
217.6    " 
273-3    " 

343-5    ' 

8.  2  pts. 
17.0    " 
37-0     ' 
64-5     ' 
98.1     " 
137.8     " 

Leidie:  C.  r.,  95,  87. 

Glycenc    fMg(C,H,O4), 

acid  salts     Ca 
(anhy-    J  Ba          " 
drous)  in      yn          « 
water.     |.J         „ 

20 

20 
20 
20 
20 

43-05  " 
9.32  " 

50.15  " 
39-03  " 
85.00  " 

22.78  " 
3.85  " 
6.60  (( 

3.87" 
4-43  " 

Franklandaud  Apple- 
yard:  J.  Chem.Soc., 
63,  310. 

Potassium  methoxy- 
succinate  in  wafer. 
Calcium  methoxy- 
succinate  in  water. 
Calcium  ethoxysucci- 
nate  in  water. 

16 

14 
15 

di4-4,  '13-9 
5-41  " 
4-15  " 

3-0     " 
0.46  " 
0.63  " 

Purdie  and  Walker: 
J.    Chem.     Soc., 
63,  222,  233. 

Calcium  gulonate  in 
water. 

15 

5-8    " 

1.6    " 

E.    Fischer:  Ber.,    25, 
1028. 

Calcium  galactonate, 
in  water. 

100 

50        " 

2.2-2.5" 

E.  Fischer  and  Hertz: 
Ber.,  25,  1253. 

Leucine  in  water. 

— 

2-44  " 

0.98  " 

Walden:  Ber.,  29,  1702. 

Inosite  in  water. 

— 

ca.  50  " 

4-56  " 

Walden:  Ber.,  29,  1702. 

Camphoric  acid  in  water 
"  alcohol 

20 
15 

6.96J  " 

112   " 

o.2392- 
33" 

1  Jungfleisch. 
2  Aschan. 
From  Beilstein,  Org.  Ch. 

Isocamphoric  acid  in 
water. 

2O 

0-347  " 

0.203  " 

Aschan:  Stud.  Campher- 
gruppe. 

Camphoronic  acid  in 
water. 

20 

16.8    " 

3-72    " 

Aschan:  Ber.,  28,  16. 

Isopropylphenylglycol- 
ic  acid  in  alcohol. 

13 

47-4    " 

21.6      " 

Fileti:  J.  prakt.  Chem., 
[2],  46,  561. 

The  lower  solubility  of  the  racemic  compounds  is  shown  ^ 
many  cases  by  the  formation  of  a  crystalline  precipitate  when 
concentrated  solutions  of  the  active  forms  are  mixed.  This  is 

£ 


82  OPTICAL    MODIFICATIONS 

true,  for  example,  of  concentrated  aqueous  solutions  of  tartar ic 
acids  (Pasteur),1  of  alcoholic  solutions  of  camphoric  acids 
(Chautard)2  and  of  many  derivatives  of  the  limonenes  as  the 
nitrosochlorides,  nitrosates,  hydrochlornitrolbenzylamines, 
hydrochlornitrolanilides,  dissolved  in  alcohol  (Wallach),1'  and 
the  flr-nitrolpiperidines dissolved  in  petroleum  ether  (Wallach).4 
Likewise,  from  a  mixture  of  the  methyl  alcohol  solutions  of 
d-  and  /-dimethyl  tartrate,  the  less  soluble  racemate  ester 
crystallizes  at  once  (Anschiitz).5 

This  rule  of  the  lower  solubility  of  the  racemic  compounds 
is,  however,  not  without  exceptions.  Thus,  the  two  active 
or-limonenebenzoylnitrosochlorides  are  less  soluble  in  acetic 
ether  than  the  crystalline  dipentene  compound  (Wallach).6 
8.64  parts  of  the  active  mandelic  acid,  and  15.97  parts  of  the 
racemic  acid  dissolve  in  100  parts  of  water  at  20° 
(Lewkowitsch).7  100  parts  of  water  dissolve  only  0.084  Part 
of  /-silver  valerate  at  20°,  but  1.181  parts  of  the  racemic  salt 
at  the  same  temperature  (Schiitz  and  Marckwald).8  d-  and/- 
dimethyldiacetyltartrat.es  are  less  soluble  in  benzene,  than  the 
diacetylracemate  ester  (Anschiitz).9  d-  and  /-barium  cam- 
phoronates  form  difficultly  soluble  precipitates,  while  the  r-salt 
is  easily  soluble  in  water  (Aschan).10  Nearly  complete  agree- 
ment in  solubility  was  found  for  d-  and  r-conine,  100  parts  of 
water  dissolving  1.80  parts  of  the  first  and  1.93  parts  of  the 
second  at  19.5°  (Ladenburg).11 

The  solubility  of  the  racemic  compounds  may  be  modified 
also  by  the  fact,  that  even  in  a  concentrated  solution  they  are 
not  in  unchanged  condition,  but  are  partly  dissociated  into 
their  antipodes.  This  has  been  shown  for  racemic  acid,  as 
mentioned,  and  also  for  its  sodium-ammonium  salt  which,  even 
in  strong  aqueous  solution,  may  be  completely  split  up  into 
the  two  tartrates.  See  §27  :  Temperature  of  Transformation. 

Pasteur  :  Dissymmetric  moleculaire,  1860. 
Chautard:  Compt.  rend.,  56,  698. 
Wallach  :  Ann.  Chem.   (I_iebig),  270,  195. 
Wallach:  Ibid.,  253,125. 
Anschiilz:  Her.  d.  chem.  Ges.,  18,  1398. 
Wallach:  Ann.  Chem.  (Liebig),  370,  177. 
Lewkowitsch  :  Her.  d.  chem.  Ges.,  16,  1566. 
Schiitz  and  Marckwald  :  Ibid.,  39,  58. 
Anschiitz:  Ann.  Chem.  (L,iebig),  347,  116. 

10  Aschan  :  Her.  d.  chem  Ges.,  38,  16. 

11  Ladenburg  :  Ibid.,  38,  165. 


MELTIXG-POINT 


24.  Melting-Point.— The  determinations  of  the  melting-points 
of  active  and  racemic  forms  of  many  crystallizable  substances 
have  failed  to  show  any  regularities.  In  some  cases,  the 
melting-point  of  the  racemic  compound  is  higher  than  that  of 
the  active  components,  while  in  other  cases  the  reverse  is  true. 
The  melting-points  may  also  be  the  same.  As  may  be  seen 
from  the  table  below,  quite  different  groups  of  bodies  are 
found  in  each  of  the  three  classes  : 


Active      **~. 


Diff- 


Observer. 


A.   Melting-point  higher  for  the  racemic  than  for  the  active  form. 


Tartaric   acid,  racemic  acid 
H  O 

170° 

20d° 

1A° 

Walden  :  Ber.,  29,  1701. 

IOO 

I  "JO  ^ 

o<+ 
10  ^ 

Walden  :  Ber.,  29,  1698. 

Dimethyl  tart,  and  racem  .  . 

45 
80 

*a"«0 

85 
108 

O^'O 

40 

IQ 

Anschiitz  :  Ber.,  18,  1307. 
Purdie  and  Marshall  :  Ch. 

Isopropylphenylglycolic 

l  =  -i    e 

Ts;6   C 

A7 

Soc.  63,  217. 
Filetti  :   Gazz.  ch.  ,  22,  II, 

Galactonic  acid,  lactone-  < 

go 

921 

1  6"^  ^ 

122 

125'-' 

l68 

33 

395- 
^chnelle    and    T.  :   L. 
Ann.,  271,83.  2Fischer: 
Ber.,  25,  1247. 

ivO'G 

187 

20  1 

•5 
16 

383- 
Smith  '  L  Ann     272  180 

Mannonic  acid,    phenylhy- 
drazide  

2jc 

**->3 
2  •?(•) 

r  c 

E  Fischer  •  Ber     23   378 

Mannoheptonic  acid,  phen- 

22O 

*&* 

°2  C 

XD 

Smith  '  L/   A.nn     272   i8s 

Mannoheptosephenylosa- 

2O7 

-•*:) 

186. 

Galactosephenylosazone  •  •  • 
Gulonic  acid,  phenylhydra- 
zide  

^*O 

195 
148 

206 
I  c/1 

II 

5 

188. 
E.  Fischer:  Ber.,  25,  1256. 

E  Fischer  °  Ber    25  1020 

187 

1O4 

T  C 

\Valden  *  Ber    29   1700 

Isocamphoric  acid.  

10/ 

171   ^ 

IOO  ^ 

X3 

IQ 

Walden  *  Ber    29  1701 

Limonenetetrabromide.  
Limonene-a-nitrolpiperi- 
dide.. 

105 

QA 

•y»a 

124 

I^A. 

AV 
19 

60 

Wallach  :Ber.,  24,  1559. 
Wallach  :  Ber..  24,  I.S.SQ. 

OPTICAL   MODIFICATIONS 


Active 
forms. 

Ra- 
cemic 
form. 

Diff. 

Observer. 

L,imonene-0-nitrolpiperi- 

72 
"7.5 

92.5 

03.5 
137 
152.5 

86.5 

168 
190 
116.5 

152° 
126 

140 
109.5 

150 
160.5 
169.5 

97 

178 
205 

42° 

13 

21 
22.5 

17 
46.5 

17 
10.5 
10 

15 

II 

Wallach  :  Ber.,  24,  1559. 
Wallach  :  Ber.,  24,  1559. 
Wallach  :  Ber.,  24,  1559. 

Wallach  :  L.   Ann.,    270, 
194. 

Wallach  :   L.   Ann.,   270, 
192 

\Vallach  :   L.    Ann.,   270, 
192. 
\Vallach  :    L.    Ann.,    272, 
108. 
Wallach:   L.    Ann.,    272, 
108. 
Wallach  :   L.    Ann.,    286, 

123. 
Baeyer  :  Ber.,  28,  640. 
Marckwald  :  Ber.,  29,  46. 
Marckwald:  Ber.,  29,  46. 

Limonene-a-nitrolanilide  •  • 

Limonenehydrochlornitrol- 

Limonene-a-nitrolbenzyl- 

Limonenehydrochlornitrol- 

Fenchylphenylsulfourea-  .  . 
0-Carvonepentabromide  .  .  . 

Caronesemicarbazide  
a-Pipecolinehydrochloride  - 

B.  Melting-point  of  the  racemic  lower  than  for  the  active  forms. 

176° 
172 

202 

/I54 

162.5 
196- 

200 

207 
132.8 

153 
'     135 

109.5 

153-5° 
160.5 
198 

85 

132.5 
175-5 

191 
118 

149 
125 

22.5° 

ii.  5 

4 

23 

16 
14.8 

4 

10 

19-5 

Walden:  Ber.,  29    1699. 
Walden:  Ber.,  29,  1699. 
Walden:  Ber.,  29,  1700. 

Fischer  and  Smith:  L,. 
Ann.,  272,  182. 

Fischer:  Ber.,  23,  2620. 

Fischer:    Ber.,    23,  2226; 
L.  Ann.,  272,  182. 
Fischer:  Ber.,  27,  1524. 
Lewkowitsch:  Ber.,  16, 
1566. 
Wallach:  Ber.,  24,  1559. 
Wallach:  Ber.,  24,  1559. 

"     L.  Ann.,  270,  176. 

Mannoheptonic  acid, 

Glucosediphenylhydra- 

Man  noheptose-phen  y  1- 

Mannitoltribenzacetal  .... 

Limonene-/3-nitrolanilide  •  . 
'  '  -hydrochlorcarvoxirm 
"  a-benzoylnitrosochlo- 

MELTING-POINT 


Active 
forms. 

Ra- 
cemic 
form. 

Diff. 

Observer. 

40° 
160.5 
II4-5 

95 

121 

142.5 
162.5 

I3I.5 
194 

147 

34° 
159 
98.5 

64-5 
108 

125 

155 

118.5 
186 
131 

6° 

1-5 
16 

30-5 
13 
17.5 
7-5 

13 
8 
16 

Wallach:  L.  Ann.,  272,  108. 
"      L.  Ann.  ,272,  108. 
"      L.  Ann.,  272,  108. 

"      L.  Ann.,  272,  108. 
"      L.  Ann.  ,286,  121. 
"      L.  Ann.,  286,  122. 
v.  Baeyer:    Ber.,  28,  640. 

Marckwald:  Ber.,  29,  46. 
Marckwald:  Ber.,  29,  46. 
Marckwald:  Ber.,  29,  46. 

Oxybenzylidene-fen- 

/3-Carvonetetrabromide  .  .  . 
a-Carvonepentabromide.  •  • 
Carvonesernicarbazide  .... 
a-Pipecoline  salts, 
C  H   N  H  \uCl 

(C6H13N)2.H2PtCl6  ... 
(C6H13N.HI)CdCl2... 

C.  Melting-points  of  the  active  and  racemic  forms  the  same. 

Galactonicacidphenylhy-  i 

drazide "...'..  2oo~-2os° 


Gulonic  acid,    phenylhy- 

drazide 

Phenylgulosazone    

Limonene-o-nitrosochlo- 


Fischer:  Ber.,  27,  3225. 

Fischer:   Ber.,  27,  3225. 
Fischer:  Ber.,  25,  1030. 


^-Monobromcamphor  .  .  . 

92.4-92.7 

uaiiacn:   L,.   Ann.,  252, 
in,  125. 
Kipping     and   Pope:    J. 
Chem.  Soc.,  67,  372. 

In  the  cases  of  those  racemic  bodies  whose  melting-points  are 
found  to  be  lower  than  those  of  the  components  there  is  the 
possibility  that  they  are  not  compounds  but  mixtures,  as  this 
relation  is  characteristic  of  mixtures.  In  fact  this  has  been 
proved  in  the  case  of  gulonic  acid  lactone.  A  mixture  of 
equal  parts  of  the  antipodes  gave  on  evaporation  of  the  aque- 
ous solution  at  first  an  inactive  crystal  mass,  the  melting-point 
of  which  (160°)  was  much  lower  than  that  of  the  active 
forms  ( 1 8 1  ° ) .  But  it  was  recognized  that  this  could  not  be  a 
racemic  compound  because  by  repeated  fractional  crystallization 
it  could  be  split  up  into  antipodes.1  Possibly  the  same  condi- 
tions will  be  disclosed  by  fuller  investigations  of  other  sub- 
stances in  group  B.  See  §  32. 

1  Fischer  and  Stahel:  Ber  d.  chem.  Ges.,  34,  534;  Fischer  and  Curtiss:  Ber.  d.  chem. 
Ges.,  35,  1025. 


86  OPTICAL   MODIFICATIONS 

In  those  cases  in  which  racemic  bodies  have  about  the  same 
melting-point  as  have  the  components,  it  is  also  probable  that 
they  are  merely  physical  mixtures.  The  conditions  then 
resemble  those  which  Kuster1  found  in  isomorphous  mixtures 
where  the  melting-points  lie  between  those  of  the  constituents. 

Then  again,  a  change  in  the  melting-point  has  been  found 
in  certain  substances.  Wallach  observed2  that  the  melting- 
point  of  racemic  y#-carvonepentabromide,  which  was  about 
96°-98°  at  the  start,  and  quite  different  from  that  of  the 
components  (86°-87°),  becomes  lower  by  repeated  crystal- 
lization of  the  preparation.  It  appears  here  that  a  partial 
decomposition  of  the  racemic  compound  must  have  taken  place. 

Walden  has  called  attention  to  the  parallelism  between 
specific  gravity  and  melting-point  of  the  optical  modifications.3 

A  consideration  of  the  above  tables  shows  in  fact,  that  with 
those  bodies  in  which  the  specific  gravity  of  the  racemic  form 
is  greater  than  that  of  the  active  components,  the  same  relation 
holds  for  the  melting-points,  and  vice  versa. 

2.  Liquid  Racemic  Compounds 

25.  On  mixing  equal  amounts  of  the  antipodes  of  liquid 
substances  it  may  happen  that  immediate  solidification  to  a 
crystalline  mass  takes  place,  which  is  inactive  in  solution  ;  in 
such  case  a  true  racemic  compound  certainly  is  formed.  This 
occurs,  for  example,  by  pouring  together  of  d-  and  /-carone- 
oxime  (v.  Baeyer).4 

If,  on  the  other  hand,  the  inactive  mixture  remains  liquid, 
it  is  uncertain  whether  it  should  be  considered  as  a  racemic 
compound.  There  is  evidently  no  ground  for  this,  if  it  be 
found  that  the  physical  properties  of  the  mixture  are' the 
same  as  those  of  the  components.  This  has  been  observed, 
for  example,  with  limonene,  also  with  carvone,  in  respect  to 
specific  gravity  and  boiling-point  (Wallach),5  conine,  with 
respect  to  specific  gravity,  boiling-point  and  solubility  (Laden- 
burg),6  further  with  the  esters  of  /-  and  inactive  glyceric  acid 

Kiister :  Ztschr.  phys.  Chem.,  5,  601  ;  8,  577. 

Wallach:  Ann.  Chem.  (Uebitf),  386,  138. 

Walden  :  Ber.  d.  chem.  Ges.,  29,  1704. 

v.  Baeyer  :  /bid.,  28,  640. 

Wallach  :  Ann.  Chem.  (I^ebig),  286,  138. 

I^adenburg  :  Ibid.,  247,  81  ;  Ber.  d.  chem.  Ges.,  28,  163. 


LIQUID    RACEMIC    COMPOUNDS  87 

and  diacetylglyceric  acid  Frankland  and  (MacGregor).1  The 
agreement  in  the  specific  gravities  of  liquid  inactive  and  active 
isomers,  leads  to  the  conclusion  that  the  inactive  forms  must 
be  considered  as  mechanical  mixtures,  as  I.  Traube  has  shown  by 
the  aid  of  his  atomic  constants  and  molecular  covolume  data.2 

Such  inactive  mixtures  may  differ  in  chemical  behavior, 
from  their  components,  d-  and  also  /-limonene  are  trans- 
formed by  bromination  into  rhombic-hemihedral  crystals  of 
the  tetrabromide,  melting  at  104°,  while  the  mixture  of  the 
two  isomers  (dipentene)  furnishes  rhombic  crystals  melting  at 
124°,  which  are  less  soluble  in  ether  than  the  first,  and  wrhich 
form  a  racemic  compound  (dipentene tetrabromide)  (Wallach).3 
The  racemization  probably  begins  here,  however,  with  the  for- 
mation of  the  crystalline  compound,  and  the  behavior  noted 
gives  no  proof  therefore  that  the  dipentene  is  already  a  real 
combination  of  the  antipodes. 

Elevation  of  the  boiling-point  could  betaken  as  an  indication 
of  raceme  formation,  but  this  has  not  yet  been  observed  in 
a  single  case  with  certainty,  experiment  showing  always 
practical  agreement  in  this  factor.  Besides,  even  with  true 
racemic  compounds,  the  possibility  is  present  of  finding  not 
their  own  boiling-point,  but  that  of  the  components,  because 
at  the  high  temperature  necessary,  dissociation  into  the  last 
may  take  place. 

The  temperature  changes  observed  on  mixing  active  isomers 
have  been  employed  to  decide  the  question  under  discussion. 
In  this  regard,  the  following  facts  are  to  be  considered : 

If  the  two  antipodes  unite  to  form  a  real  racemic  compound, 
which  immediately  separates  in  crystalline  form,  the  increase 
of  temperature  observed  is  due  partly  to  the  heat  of  formation 
and  partly  to  change  in  the  state  of  aggregation.  This  is,  for 
example,  the  case  wrhen  concentrated  solutions  of  d-  and  /- 
tartaric  acid  (Pasteur),  or  d-  and  /-limonenetetrabromide  in 
ether,  are  mixed.4  With  the  tartaric  acid  there  is  also  the 
heat  of  hydra tion,  in  consequence  of  forming  racemic  acid, 

c,H6o6  +  H,O. 

1  Frankland  and  MacGregor  :  J.  Chem.  Soc.,  63,  511! 
-  I.  Traube  :  Ber.  d.  chem.  Ges.,  29,  1394. 

Wallach  :  Ann.  Chem.  (Liebig),  286,  138. 
4  l,adenburg:  Ber.  d.  chem.  Ges.,  28,  1994. 


88  .  OPTICAL   MODIFICATIONS 

If  the  two  antipodes  are  themselves  liquid  substances,  and 
if  no  solid  racemic  body  separates  on  mixing  them,  then  a 
change  of  temperature  may  be  due  :  first,  to  the  heat  of  solu- 
tion or  dilution,  or,  secondly,  to  the  possible  formation  of  a 
liquid  racemic  compound. 

Regarding  the  heat  of  solution  observed  on  pouring  together 
two  miscible  liquids,  this  may  be  shown  according  to  the 
nature  of  the  substances,  and  the  proportions  even,  in  a 
decrease  of  temperature  as  well  as  by  an  increase.  As 
investigations  of  Bussy  and  Buignet,1  and  also  of  Favre,2  have 
disclosed,  the  heat  effect  bears  no  definite  relation  to  change 
of  density  which  takes  place.  Thus,  alcohol  and  ether  mixed 
with  contraction,  carbon  disulphide  and  chloroform  with  expan- 
sion, but  in  both  cases  there  is  a  decrease  in  temperature.  If 
alcohol  and  chloroform  be  mixed  in  different  proportions,  there 
is  always  contraction,  but  in  spite  of  this,  reversed  temperature 
changes  may  be  found,  as  shown  by  the  following  example  : 

Mixing  proportions.  Temp,  change. 
6    niols.  chloroform  -    i  mol.    alcohol  —  2.5° 

i^  mols.  chloroform  —  i  mol.    alcohol  o.o 

i    mol.    chloroform  -j-  6  mols.  alcohol  4   4.2° 

In  general,  as  late  investigations  of  Ladenburg'  have  also 
shown,  large  changes  in  volume  seem  to  correspond  to  large 
temperature  changes.  If  the  contraction  or  dilatation  is  very 
small,  that  is,  if  the  specific  gravity  of  the  mixture  is  very 
nearly  that  of  the  mean  calculated  from  the  mixing  pro- 
portions, a  very  small  temperature  change  is  in  general  noted, 
as  in  the  case  of  methyl  and  ethyl  alcohol,  isobutyl  and  iso- 
amyl  formate,  xylene  and  toluene,  and  soon  (Ladenburg). 
But,  on  the  other  hand,  large  temperature  changes  have  been 
observed  ;  thus,  on  mixing  two  volumes  of  ether  with  three 
volumes  of  carbon  disulphide  there  is  no  change  of  volume, 
but  notwithstanding  this,  there  is  a  fall  of  temperature  of  3.6° 
(Bussy  and  Buignet),  and  this  is  the  case  with  some  very 
similar  liquids,  such  asd-  andAconine,  with  which  Ladenburg1 

1  Bussy  and  Buignet  :  Jahr^sbericht,  1864,  62  1069.    Ann.  chim.  phys.,  [4],  4,  5. 
a  Favre  :  Jahresbericht,  1864,  66.     Compt.  rend.,  59,  783. 
*  L,adenburg  :  Ber.  d.  chem.  Ges.,  28,  1991. 
«  I^adenburg :  /bid.,  28,  164. 


LIQUID    RACEMIC   COMPOUNDS  89 

found  a  fall  of  temperature  of  1.4°.  But  d-  and  /-limonene 
mix  without  appreciable  change  of  temperature.1 

As  the  above  relations  show,  the  temperature  changes 
accompanying  mixing  or  solution  are  of  such  different  kinds, 
that  the  heat  effects  in  consequence  of  a  real  combination  of 
the  antipodes  may  be  quite  uncertain.  Therefore,  neither  an 
increase  nor  decrease  of  temperature  which  may  be  observed  on 
mixing  two  active  isomers,  may  be  taken  as  definitely 
indicating  the  existence  of  racemization. 

Finally,  it  may  be  remarked,  that  it  has  been  found 
impossible  through  cryoscopic  measurements  also  to  prove 
racemization  in  liquid  inactive  bodies.  Thus,  Frankland  and 
Pickard2  found  the  simple  molecular  weight  for  the  inactive 
methyldibenzyl  ester  of  glyceric  acid  dissolved  in  acetic  acid, 
benzene,  nitrobenzene  or  ethyl  bromide. 


26.  The  following  may  be  given  as  the  principal  results  of 
all  of  the  above  comparisons  of  the  properties  of  racemic  com- 
pounds with  those  of  the  active  modifications  : 

r .  True  racemic  compounds  are  found  only  among  crystal- 
lizable  substances.  They  have  always  a  different  crystalline 
form,  and  often  an  amount  of  water  of  crystallization  different 
from  that  of  the  active  isomers.  Further,  they  show,  as  a 
rule,  deviations  in  respect  to  specific  gravity,  melting-point 
and  solubility,  but  often  in  different  directions. 

2.  Inactive    crystalline    masses  may    be  sometimes   simple 
aggregations   or    growths   of    mixed    enantiomorphic   active 
crystals. 

3.  The  existence  of  liquid  racemic'compounds  is  improbable, 
and  up  to  the  present  time  has  not  been  shown. 

The  question  as  to  whether  an  inactive  body  is  a  racemic 
compound  or  racemic  mixture  is  besides,  in  many  cases,  only 
of  secondary  importance.  Both  forms  may  be  split  up  into 
optical  antipodes  in  the  same  wray,  and  in  this  we  have  all 
that  is  really  important  in  the  respective  substances,  that  is, 
their  distinction  from  inactive  configuration  isomers. 

1  I^adenburg  :  Ber.  d.  chem.  Ges.,  28,  1994. 

-  Frankland  and  Pickard  :  J.  Chem.  Soc.,  69,  128. 


QO  FORMATION    OF   RACEMIC    BODIES 

C.  Formation  of  Racemic  Bodies 
Racemic  bodies  may  be  produced  in  the  following  ways  : 

1 .  By  direct  combination  of  the  active  antipodes. 

2.  From  one  of  the  active  forms  by  action  of  higher  tem- 
perature. 

3.  By  the   chemical   transformation   of   asymmetric   bodies 
into  asymmetric  derivatives. 

4.  By  the    conversion    of  inactive    symmetric   bodies  into 
asymmetric  compounds. 

27.  Production  of  Racemic  Bodies  by  Combination  of  Equal 
Amounts  of  the  Antipodes.  Temperature  of  Transition. — Certain 
phenomena  may  appear  here  which  belong  in  the  class  of 
chemical  equilibrium  reactions,  the  important  characteristic  of 
which  is,  that  for  them  a  definite  temperature  exists  which, 
if  passed  in  the  one  direction  or  in  the  other,  leads  to  the 
transition  of  one  system  of  bodies  into  another  or  the  reversion 
of  the  latter  into  the  former.  Thus,  the  breaking  up  of  a 
racemic  body  into  its  antipodes  is  possible,  or,  on  the  other 
hand,  the  reproduction  of  the  racemic  from  the  antipodes. 
The  transition  temperature  has  been  determined  in  but  two 
cases : 

First  :  with  sodium  ammonium  racemate  and  the  two  cor- 
responding tartrates.  When  Pasteur  permitted  a  solution  of 
racemic  acid  which  was  saturated,  half  with  soda  and  half  with 
ammonia,  to  evaporate  spontaneously,  he  obtained  separate 
crystals  of  the  d  and  /  double  tartrate  salt.  But  on  repeating  the 
experiment,  it  did  not  always  succeed  ;  thus,  Staedel1  observed 
only  the  formation  of  the  racemate.  Scacchi'2  first  noticed 
that  the  kind  of  crystal  which  separates  depends  on  the  tem- 
perature at  which  the  evaporation  takes  place,  and  WyroubofF 
then  determined  28°  as  about  the  limiting  temperature  above 
which  racemate,  and  below  which,  on  the  contrary,  the 
tartrates,  crystallize  out.  A  complete  explanation  of  the 
phenomenon  was  first  given  by  van'  t  Hoff  and  Deventer,4  when 

1  Staedel:  Ber.  d.  chem.  Ges.,  n,  1752  (1878). 
1  Scacchi:  Rendiconti  dell  Accad.  di  Napoli.  1865,  250. 
1  Wyrouboff  :  Bull.  Soc.  Chim.,  45,  52  (1886)  ;  Compt.  rend.,  102,  627. 
4  Van't  Hoff  and  Deventer:  Ber.  d.  chem.  Ges.,  19,  2148(1886);  Ztschr.  phys.  Chem., 
i.  165. 


TRANSITION    TEMPERATURE  91 

they  showed  that  we  have  to  deal  with  a  process  here  which 
can  also  take  place  outside  of  solution.  If  a  finely  powdered 
mixture  of  equal  parts  of  right  and  left  sodium  ammonium 
tartrate,  NaNH4C4H4O6 -f  4H2O,  be  sealed  in  a  tube  and 
exposed  to  a  temperature  which  is  kept  below7  27°,  it  remains 
quite  unchanged  ;  but  above  27°  the  formation  of  crystals  of 
the  racemate,  NaNH4C4H4O6  -f  H2O,  sets  in,  water  being 
liberated  at  the  same  time  which  partially  liquefies  the  mass. 
On  the  other  hand,  if  powdered  sodium  ammonium  racemate 
be  mixed  with  water  below  27°  in  the  proportion  of 
2(XaNH4C4H4O6  +  H2O)  :  6H2O,  the  semi-fluid  mass  which 
forms  at  first,  solidifies  after  a  time  to  a  dry  mixture  of  the 
two  tartaric  acid  salts.  Above  27°  this  does  not  happen.  The 
two  reactions  may  be  expressed  by  the  following  equations  in 
which  T=  C4H4O6 : 

Stable  below  27°.  Stable  above  27". 

d  NaXH4  T  —  4H2O  )  \r  [NaNH4  T  +  H2O]2 

/  NaNH4  T  —  4H2O  /  \  6H2O 

The  change  of  one  salt  into  the  other  may  be  recognized  by 
aid  of  a  dilatometer,  which  is  filled  partly  with  a  mixture  of 
the  two  tartrates  and  partly  with  oil;  the  slow  formation  of 
the  racemate  between  26.7°  and  27.7°  is  accompanied  by  a 
marked  increase  in  volume. 

Further  investigations  of  van't  Hoff,  Goldschmidt  and 
Jorissen1  showed  that  the  sodium  ammonium  racemate 
(XaNH4C4H4O6  -f-  H2O),  when  heated  to  about  35°,  under- 
goes a  further  change  as  it  breaks  up  into  sodium  racemate 
and  ammonium  racemate,  according  to  the  equation: 

2[NaNH4r.H20]2  =  [N'a,  T],  -  [(NH4)2^]2  +  4H2O. 

Sodium  ammonium  racemate  can  exist  in  solution,  therefore, 
only  within  the  narrow  temperature  limits  of  27°  to  35°. 

Again,  it  can  happen  that  the  separation  of  the  double 
racemate  may  fail  when  a  mixture  of  d-  and  /-sodium  ammo- 
nium tartrates  is  exposed  to  a  temperature  higher  than  27°, 
for  example,  to  30°,  and  instead  a  separation  of  crystals  follows, 
consisting  of  a  mixture  of  sodium  racemate  and  ammonium 
racemate  as  in  the  last  case.  This  is  especially  true  when 

1  van't  Hoff,  Goldschmidt  and  Jorissen:  Ztschr.  phys.  Chem.,  17,  49. 


92  FORMATION   OF    RACEMIC    BODIES 

crystals  of  the  last   named  salts  are  added  to    the   solution. 
The  change  may  be  represented  in  this  way: 

d  2[NaNH4  T  +  4H20]  V  f 

/2[N.NH47'-f4HfO]J  l 

The  methods  by  which  the  transition  temperatures  of  30° 
and  35°  were  established  consisted  in  tensimetric  observations 
and  determinations  of  solubility. 

Analogous  relations,  according  to  experiments  of  van't 
Hoff,  Goldschmidt  and  Jorissen,1  have  been  found  to  exist  in 
the  case  of  the  potassium  sodium  racemate  [KNaC4H4O6  + 
3H2O]2,  described  by  Wyrouboff,2  and  d-  and  /-Rochelle  salt, 
KNaC4H4O6  -f-  4H2O.  A  solution  formed  from  the  racemate 
or  from  the  two  tartrates  is  found  in  the  following  conditions 
according  to  the  temperature. 

1.  Below  about  —6°  d-  and  /-potassium  sodium  tartrate  exist 
in  solution  together: 

2.  From  about  —  6°  on  the  combination  to  potassium  sodium 
racemate  begins,  and  especially  on  an  addition  of  small  crystals 
of  this  salt: 

d  KNa  T  -  4H20  )  f  [KNa  T  +  3H,O]2 

/ 


-r  4H2O  I  2H2O 

3.  The  double  racemate  exists  up  to  the  temperature  of  41°; 
from  that  point  it  decomposes  into  the  sodium  racemate,  [Na.,  T  J  2, 
and   potassium   racemate,,    [K27^  -f-   2H2O]2  according  to  the 
equation: 

2[KNa7-  +  3H,0],  =  [Na2T]2  +  [K,7>  2H2O]2  -f  8H2O. 

4.  If  the  formation  of  the  potassium  sodium  racemate  from 
the  two  tartrates  fails,  which  may  happen  by  excluding  every 
trace  of  the  first  named  salt,  a  conversion  of  the  tartrates  into 
potassium  racemate  and   sodium  racemate  is  possible.     This 
takes  place  at  a  temperature  of  33°: 

d  2(KNar+  4H,0)  \ 


Therefore  under  varying  conditions  very  different  salts  may 
crystallize  from  the  solution. 

!  van  't  Hoflf,  Goldschmidt  and  Jorissen:  /tschr.  phys.  Chem.,  17,  505. 
3  Wyrouboff:  Ann.  chini.  phys.  [6],  9,  224. 


PRODUCTION    OF    RACEMIC    BODIES    BY   HEAT  93 

Exact  knowledge  of  transition  temperatures  extends  only  to 
the  two  salts  just  described. 

With  a  number  of  substances  it  has  been  observed  that  when 
mixed  solutions  of  their  antipodes  are  allowed  to  evaporate 
under  ordinary  conditions  of  temperature  active  crystals  only, 
never  racemic,  are  formed.  Thus,  Piutti1  did  not  succeed  in 
uniting  d-  and  /-asparagine  to  form  a  racemic  compound,  while 
it  was  possible  with  d-  and  /-aspartic  acid.  As  already 
remarked,  according  to  Fisher  and  Curtiss,2  the  lactone  of  d- 
and  /-gulonic  acid  separates  in  independent  enantiomorphous 
crystals,  wThile,  on  the  other  hand,  a  racemic  calcium  salt  and 
phenylhydrazide  may  be  obtained.  It  has  likewise  been  found 
impossible  to  obtain  by  crystallization  racemic  forms  of  several 
other  bodies,  as  the  zinc  ammonium  salt  of  active  lactic  acid, 
glutaminic  acid,  glutaminic  acid  hydrochloride,  homo-aspartic 
acid  and  camphoric  acid.  In  all  of  these  cases  it  cannot  be 
assumed  that  the  antipodes  do  not  possess  the  property  of 
uniting  to  form  a  racemic  body;  knowledge  of  the  transition 
temperatures  simply  is  lacking. 

28.  Production  of  Racemic  Bodies  from  One  of  the  Active  Forms 
by  Heat. — By  long  application  of  heat,  many  active  substances 
suffer  a  gradual  decrease  in  their  rotating  power,  without 
undergoing  a  change  in  composition.  It  was  at  first  supposed 
that  a  destruction  of  the  active  property  took  place,  but  the 
phenomenon  was  later  recognized  as  one  of  racemization.  In 
consequence  of  the  enlarged  atomic  motion  by  increase  of 
temperature,  a  conversion  into  molecules  of  the  opposite  modi- 
fications follows  until  finally  a  condition  of  equilibrium  is 
established,  in  which  just  as  many  molecules  of  the  ^-form 
are  changed  into  the  /-form  as  vice  versa,  that  is,  in  which  the 
mixture  consists  of  equal  amounts  of  the  two  antipodes.  Van 't 
HofF  has  treated  the  question  from  the  standpoint  of  thermo- 
dynamics. 

The  phenomenon  was  first  observed  by  Pasteur4  in  the  case 
of  tartaric  acid,  when  he  heated  ^-cinchonine"  tartrate  five  or 

1  Piutti:  Ber.  d.  chem.  Ges.,  19,  1694. 

-  Fischer  and  Curtiss  :  Ber.  d.  chem.  Ges.,  25,  1025. 

:!  van  't  Hoff  :  ^agerung  der  Atome  im  Raum,  2nd  ed.,  p.  33. 

4  Pasteur  :  Compt.  rend.,  37,  162  (1853). 


Q4  FORMATION    OF    RACEMIC    BODIES 

six  hours  to  a  temperature  of  165°  to  175°  in  an  oil-bath.  The 
alkaloid  was  changed  first,  being  converted  mainly  into  cin- 
chonicine,  and  then  the  production  of  racemic  acid  gradually 
followed,  which  was  recovered  by  conversion  into  the  calcium 
salt.  /-Cinchonine  tartrate  behaves  in  a  similar  manner.  The 
alkaloid  takes  no  part  in  the  reaction,  it  only  protects  the 
tartaric  acid  from  destruction  by  the  heat.  The  formation  of 
racemic  acid  follows  also  when  dry  tartaric  acid  is  heated  to 
170°  to  180°,  and  likewise,  by  boiling  its  aqueous  or  weak 
hydrochloric  acid  solution  several  days,  which,  however, 
brings  about  a  conversion  of  only  a  few  per  cent.1  Racemiza- 
tion  follows  almost  completely  on  heating  30  grams  of  tartaric 
acid  with  3  or  4  cubic  centimeters  of  water  for  thirty  hours  to 
175°  (Jungfleisch).2  Further,  tartaric  acid,  in  the  form  of  its 
ethyl  ester,  is  very  easily  changed  by  boiling  into  racemic  acid 
(Pasteur).3  The  addition  of  several  bodies  aids  the  change  ; 
when  tartaric  acid  is  mixed  with  some  aluminum  tartrate  and 
heated  in  an  autoclave  to  140°  a  conversion  into  racemic  acid 
follows  quickly,  but  some  mesotartaric  acid  is  produced  at  the 
same  time  (Jungfleisch).4 

Racemization  by  high  and  long  heating  in  closed  tubes  has 
been  observed  in  other  substances,  as : 

l-Aspartic  Acid. — The  transition  takes  place  easily  when 
an  aqueous  solution  of  the  hydrochloric  acid  compound  is 
heated  some  hours  to  170°  or  180°  (Michael  and  Wing).5 

d-  and  l-Mandelic  Acid. — Small  amounts  (3  or  4  grams)  of 
the  dry  substance,  thirty  hours  to  160°  (Lewkowitsch).* 

d-  and  l-Isopropylphenylglycolic  Acid. — Heating  for  forty 
hours  with  water  to  180°  or  200°  (Fileti).7 

d-Camphoric  Acid. — Heating  with  a  little  water  to  170°  or 
180°  (Jungfleisch,8  Friedel).9 

The  active    terpenes    suffer  a    decrease    in  rotation   when 

Dessaignes:  Jahresbericht,  (1856),  463;  (1863),  301. 

Jungfleisch:  Compt.  rend.,  75,  439,  1739. 

Pasteur  :  Loc.  i  it. 

Jungfleisch  :  Compt.  rend.,  85,  805. 

Michael  and  Wing:  Her.  d.  chem.  Ges.,  17,  2984. 

Lewkowitsch  :  Ibid.,  16,  2721. 

Fileti  :  Gazz.  chim.  ital.,  aa,  II,  395. 

Jungfleisch  :  Jahresbericht,  (1873),  631. 

Friedel  :  Compt.  rend.,  108,  978. 


PRODUCTION    OF    RACEMIC    BODIES    BY    HEAT  95 

heated  to  about  250°  to  300°,  but  show  at  the  same  time  an 
elevation  in  the  boiling-point  and  specific  gravity,  from  which 
it  follows  that  polymerization  as  well  as  racemization  has 
taken  place,  d-  as  well  as  /-limonene  and  pinene  are  converted 
into  dipentene,  partly  also  into  terpinene  (Wallach). 

The  temperature  of  racemization  is  not  in  all  cases  as  high 
as  for  the  bodies  given  above.  As  Wallach1  found,  d-  and 
/-limonene  hydrochloride  have  the  property  of  changing 
gradually  even  at  the  ordinary  temperature.  A  preparation 
which  was  examined  when  produced,  and  after  having  been 
kept  several  weeks  showed  a  decrease  in  rotation  from  \oi\D 
=  +  39-5°  to  6.2°,  which,  as  could  be  demonstrated,  was  due 
to  the  conversion  into  the  dipentene  compound.  Besides,  the 
boiling-point  of  the  substance,  which  was  originally  97.5°, 
increased  to  about  170°  (under  j.i  mm.),  which  indicated 
polymerization  at  the  same  time. 

In  some  cases  it  has  been  observed  that  racemization  is 
hastened  by  addition  of  certain  substances  and  is  completed  at 
a  much  lower  temperature.  As  already  mentioned  tartaric 
acid  in  presence  of  aluminum  tartrate  is  easily  converted  into 
racemic  acid.  Active  amyl  alcohol  when  heated  alone  must  be 
maintained  a  long  time  at  250°  to  300°  to  lose  its  rotating 
power,  but  on  treatment  with  sodium  or  with  caustic  potash 
the  change  is  much  more  rapid;  from  the  inactive  product 
obtained  dextroamyl  alcohol  could  be  separated  by  aid  of 
fungi  (Le  Bel).2  On  repeating  this  experiment  Borucki3  found 
that  when  amyl  alcohol  was  heated  with  potash  in  an  auto- 
clave during  ten  hours  to  160°  the  angle  of  rotation,  aD  for  i 
dm.,  decreased  from  1.01°  to  o.  10°,  and  that  by  heating  under 
ordinary  pressure  with  renewed  alkali,  complete  inactivity 
resulted  only  after  465  hours.  According  to  Walden4  almost 
perfect  inactivity  may  be  reached  much  more  rapidly  by  dis- 
solving one-tenth  its  weight  of  sodium  in  the  amyl  alcohol  and 
heating  then  3^  hours  to  200°  or  220°  in  an  autoclave.  Erlen- 
meyer  and  Hell5  have  observed  that  by  treating  </- valeric  acid 

1  Wallach  :  Ann.  Chem.  (Liebig),  270,  190. 
-  t,e  Bel:  Bull.  Soc.  Chim.,  [2],  25,  545. 

3  Borucki:  Inaug.  Diss.,  Berlin,  1866;  Centrbl.,  1887,  p.  580. 

4  Walden:  Ztschr.  phys.  Chem.,  17,  711. 

'•>  Erlenmeyer  and  Hell:  Ann.  Chem.  (I«iebig),  160,  302. 


96  FORMATION    OF    RACEMIC    BODIES 

from  fermentation  amyl  alcohol  with  a  few  drops  of  strong 
sulphuric  acid  and  heating  then  ^  hour  in  a  sealed  tube  to 
250°  complete  inactivity  resulted.  Whether  this  was  due  to 
racemic  formation  or  not  was  not  established.  Active  leucine 
which  is  not  changed  by  heating  with  wrater  to  170°-! 80°  is 
converted  by  addition  of  baryta  water  at  150°-! 60°  into  the  r- 
compound  (Schulze  and  Bosshard).1  The  racemization  of 
terpenes  is  hastened  by  addition  of  sulphuric  acid,  either  con- 
centrated or  diluted  with  alcohol  (Wallach).2 

29.  Racemization  by  Conversion  of  Asymmetric  Bodies  into 
Asymmetric  Derivatives. — If  an  active  molecule  retains  its  con- 
stitution in  a  chemical  change,  that  is,  for  example,  if  a  change 
of  an  acid  into  ester,  salt  or  amide,  or  of  an  alkaloid  into  a 
combination  with  an  acid  is  concerned,  the  activity  is  always 
retained.  This  is  the  case  also  with  simple  transitions,  as  of 
active  amyl  alcohol  into  valeric  acid,  camphor  into  camphoric 
acid,  asparagine  into  aspartic  acid  and  maleic  acid,  amygdalin 
into  amygdalic  or  mandelic  acid,  etc. 

But  under  certain  conditions  the  product  may  be  inactive. 
This  is  particularly  the  case  in  the  production  of  derivatives 
in  which  the  atoms  directly  united  to  the  asymmetric  carbon 
take  a  part  in  the  reaction.  If,  for  example,  in  active  malic 
acid,  CO,H— *CH.OH— CH2— CO2H,  the  hydroxyl  group  in 
combination  with  the  *C  be  replaced  by  Br  by  aid  of  hydro- 
bromic  acid,  racemic  bromsuccinic  acid,  CO2H — *CH.Br — 
CH,— CO2H,  results  (Kekule).3  Further,  /-valeric  acid, 
(C2H5)—  *CH— (CH3)(CO.2H),  is  converted  completely  into 
racemic  bromvaleric  acid,  (C2H5)—  *CBr—  fCHs)(CO2H),  by 
treatment  with  bromine  and  phosphorus  at  a  low  temperature 
followed  by  heating  to  100°  (Schiitz  and  Marckwald).4  The 
same  active  valeric  acid  when  oxidized  in  aqueous  solution  by 
potassium  permanganate  yields  racemic  oxy valeric  acid, 
(C,H6).*COH.(CH3)  (CO2H). 

In  changes  like  the  above,  by  keeping  the  temperatures  as 
low  as  possible,  the  racemization  may  be  often  prevented  and 

1  Schulze  and  Bosshard:  Ztschr.  physiol.  Chem.,  10,  135. 

2  Wallach:  Ann.  Chem.  (I<iebig),  337,  2X3;  339,  11. 
Kekule:  Ibid.,  130,25. 

<  Schiitz  and  Marckwald:  Ber.  d.  chem.  Ges.,  39,58. 


FROM    SYMMETRIC    COMPOUNDS  97 

an  active  derivative  obtained.  Walden1  succeeded  in  con- 
verting maleic  acid  into  dextromonochlorsuccinic  acid  by  the 
action  of  phosphorus  pentachloride  with  addition  of  chloroform 
which  prevented  the  temperature  from  exceeding  62°.  By  the 
same  process2  (PC15  or  PBr5  and  CHC13)  he  converted  a 
number  of  hydroxy  acids  or  their  esters  directly  into  active 
halogen  derivatives,  as,  for  example,  /-dimethyl  and  diethyl 
malate  into  dextrobromsuccinic  esters  ;  ^-diethyl  tartrate  into 
/-ethyl  monobrommalate  ;  /-ethyl  and  propyl  mandelates  into 
dextrophenylchloracetic  esters  ;  /-mandelic  acid  into  ^-phenyl- 
chloracetyl  chloride,  C6H5.CHC1.COC1  (by  heating  with  PC15 
to  160°  under  a  return  condenser  without  addition  of  chloro- 
form); /-calcium  lactate  (without  chloroform)  into  a'-chlor- 
propionyl  chloride,  CHS.CHC1.COC1. 

The  same  reactions  which  bring  about  racemization  when 
taking  place  at  the  *C  permit  the  formation  of  active 
derivatives  from  active  substances  wrhen  the  *C  remains 
untouched.  If  the  substance  contains  several  *C  atoms,  at 
least  one  of  them  must  be  excluded  from  the  reaction 
if  active  derivatives  are  to  be  secured.  From  borneol, 
C10H1T.OH,  active  bornyl  chloride,  C10H17C1,  is  produced  by 
action  of  HC1  or  PC15  (Kachler).3  Camphor  furnished 
by  action  of  bromine  active  bromcamphor,  C10H15BrO 
(Montgolfier).4  In  the  oxidation  of  active  substances  with 
permanganate,  active  oxidation  products  result  in  many  cases ; 
thus,  chitenine,  C19H22N2O4,  from  quinine,  C20H24N2O2(Skraup),5 
chincotenine,  C18H20N2O3,  from cinchonine,  C]9H22N2O  (Hesse).6 

30.  Production    of    Racemic    Compounds  by  Conversion   of  Sym- 
metric    Bodies     into   Asymmetric. — If   a   symmetric   compound, 

Ri 
R3— C— R3,  in  consequence  of  the  substitution  of  one  of  the  two 

R2 
radicals  R.A  ^?3  by  R±  be  converted  into  an  asymmetric  com- 

1  Walden  :  Ber.  d.  chem.  Ges.,  26,  210. 

-'  Walden  :  Ibid.,  28,  1287. 

!  Kachler  :  Ann.  Chem.  (Ijebig),  197,  93. 

4  Montgolfier  :  Ann.  chim.  phys.,  [5],  i4,  140. 

•>  Skraup  :  Ann.  Chem.  (I<iebig),  199,  344. 

'•  Hesse:  Ibid  ,  176,  233. 

7 


98  FORMATION   OF    RACEMIC    BODIES 


pound,  the  formation  of  both  R3—  C—  R4    and    R4—  C—  R3   is  pos- 

R,  R, 

sible.  On  account  of  the  symmetry  of  the  original  molecule 
there  is  no  reason  why  one  of  these  antipodes  only  should  be 
formed  ;  on  the  contrary,  the  production  of  both  with  equal 
rapidity  should  take  place,  and  the  resulting  product  would  be 
racemic.  The  correctness  of  this  view  has  been  shown  by 
experience,  as  it  has  been  possible  to  prove  that  the  inactivity 
of  all  asymmetric  bodies  which  have  not  been  made  from  active 
ones,  depends  in  reality  on  the  production  of  racemic  forms. 
While  it  is  true  that  not  all  of  these  inactive  products  have 
been  split  up  into  their  antipodes,  enough  such  reactions  have 
been  carried  out  to  show  the  generality  of  the  rule. 

31.  Racemic  Compounds  from  Right-  and  Left-Rotating  Isomers 
of  Different  Configurations.  —  Such  bodies,  which  should  be  active, 
have  not  yet  been  produced.  Liebermann1  obtained,  by 
evaporating  an  ethereal  solution  of  equal  weights  of 
^-cinnamic  acid  dibromide  (  [<*]/>  ==  -+•  64°)  and  /-allocimiamic 
acid  dibromide  ([«]/>  =  -  70°),  a  residue  which  on  treatment 
with  carbon  disulphide  could  be  separated  into  the  components. 
E.  Fischer*  has  attempted  to  combine  compounds  with  each 
other  whose  configurations  present  only  partially  the  object- 
reflection  relation,  as  is  the  case  with  : 

^-Gluconic  acid.  /-Mannonic  acid. 

COOH  COOH 

I  I 

H—  C—  OH  H—  C—  OH 

HO—  C—  H  H—  C—  OH 

H—  C—  OH  HO—  C—  H 

H—  C—  OH  HO—  C—  H 

CH.OH  CH.OH 

From  a  mixture  of  equal   parts  of  the  two  acids  which  was 
evaporated    to   a   sirup,    pure   /-mannonic  acid    lactone    only 

1  lyiebermann  :  Her.  d.  chem.  Ges.,  37,  2045. 
8  Fischer  :  Ibid.,  27,  3226. 


RESOLUTION   OF    RACEMIC    BODIES  99 

separated,  and  from  a  mixture  of  the  calcium  salts,  ^-calcium 
gluconate  crystallized  first. 

The  oppositely  rotating  forms  of  camphoric  acid  and  iso- 
camphoric  acid  do  not  unite  to  yield  a  racemte  compound 
(Aschan).1 

A  tendency,  therefore,  toward  the  formation  of  such  half- 
racemic  bodies  does  not  appear  to  exist. 

D.  Resolution  of  Racemic  Bodies 

For  the  decomposition  of  racemic  bodies  into  the  anti- 
podes, we  have  as  yet  three  methods,  wrhich  were  all  dis- 
covered by  Pasteur,  and  first  applied  to  racemic  acid.  These 
are  : 

1.  Resolution  by  crystallization. 

2.  Resolution  by  aid  of  active  compounds. 

3.  Resolution  by  aid  of  fungi. 

The  principles  underlying  these  methods  have  been  explained 
already  and  it  remains  to  discuss  in  this  chapter  the  practical 
methods  of  carrying  out  the  processes. 

i.  Resolution  by  Crystallization.     Spontaneous  Resolution 

32.  This  process  depends  on  the  facts  that  racemic  com- 
pounds in  solution,  under  proper  temperature  conditions,  break 
up  into  their  antipodes  and  that  these  last  may  be  separated  by 
evaporation  of  the  solution  in  the  state  of  enantiomorphic 
crystals  which  may  be  sorted  out  by  aid  of  the  characteristic 
planes  into  active  right  and  left  forms.  Equal  amounts  of  the 
two  antipodes  are  .obtained.  The  transition  temperatures 
explained  in  §  27  must  be  considered  as  these  are  different  for 
different  substances. 

The  method  was  first  applied  by  Pasteur  in  1848  for  the 
splitting  of  racemic  acid  in  the  form  of  sodium-ammonium 
salt  and  may  be  best  carried  out  in  the  following  manner  ::{  An 
aqueous  solution  of  racemic  acid  is  divided  into  two  parts,  one 
being  saturated  with  sodium  carbonate  or  hydroxide  and  the 
other  with  ammonia  in  excess.  The  mixture  is  then  evapo- 

1  Aschan  :  Ber.  d.  chetn.  Ges.,  27,  2001. 

-  Pasteur:  Ann.  chim.  phys.  [3],  24,  442  (1848). 

3  Pasteur:  Ibid.,  28,  56  (1850). 


100  RESOLUTION   OF    RACEMIC    BODIES 

rated  on  the  water-bath  until  crystallization  begins  on  cooling. 
The  crystals  are  redissolved  by  the  aid  of  water  and  a  little 
ammonia  after  which  the  solution  is  allowed  to  stand  in  a  wide 
crystallizing  dish  for  spontaneous  evaporation.  As  explained 
in  §  27  the  temperature  must  be  kept  below  27°.  It  is  advi- 
sable to  remove  a  part  of  the  crystals  each  morning,  because, 
in  consequence  of  the  rise  of  temperature  during  the  day, 
partial  solution  might  follow  with  loss  of  the  hemihedral  faces. 
As  the  solution  gradually  loses  ammonia  a  little  must  be  added 
from  time  to  time,  sufficient  to  maintain  a  weak  alkaline 
reaction.  The  separated  crystals  which  are  illustrated  in  Figs. 
4  and  5,  and  which  often  reach  a  length  of  several  centimeters, 
are  removed  from  time  to  time  by  the  aid  of  pincers  and  sorted 
out  after  examination  with  a  magnifying  glass.  If  the  indi- 
vidual crystals  have  grown  together  or  are  united  into  groups 
it  is  best  to  bring  them  into  solution  by  adding  a  little  water 
and  warming  and  then  repeat  the  whole  crystallization.  The 
separation  of  the  d-  and  /-sodium  ammonium  tartrate  is  facili- 
tated by  placing  the  two  kinds  of  crystals  in  the  evaporated 
liquid  at  the  start  and  as  far  apart  as  possible. 

Very  often  the  crystallographic  examination  is  difficult 
because  the  hemihedral  faces  are  but  imperfectly  developed,  or 
cannot  be  found  at  all.  In  such  a  case  the  question  as  to 
whether  a  crystal  consists  of  the  right  or  left  tartrate  or  of 
the  racemate  may  be  decided  by  a  procedure  suggested  by 
Anschiitz1  which  depends  on  this  that  the  calcium  racemate  is 
much  less  soluble  than  the  two  calcium  tartrates.  The  mother 
liquor  is  separated  from  the  crystals  by  washing  with  a  little 
water,  a  fragment  is  dissolved  in  a  small  volume  of  water  and 
the  solution  is  divided  into  two  parts.  One  part  is  mixed  with 
about  3  cc.  of  a  saturated  solution  of  dextro-calcium  tartrate 
and  allowed  to  stand  some  time;  if  a  precipitate  appears  it 
shows  the  presence  of  the  left  tartrate.  If  a  precipitate  does 
not  form  and  if  the  other  half  of  the  liquid  gives  a  precipitate 
with  a  solution  of  levo-calcium  tartrate  the  presence  of  the 
right  tartrate  is  indicated.  Finally,  if  precipitation  takes  place 
in  both  cases,  racemic  acid  is  shown  to  be  present  in  thecrystal. 

As  Pasteur2  found,  the  d-  and  /-tartrates   separate  always  in 

1  Anschiitz:  Ann.  Chem.  (Iyiebig),  226,  193. 
»  Pasteur:  Ann.  chim.  phys.  [3],  34,  458. 


BY    CRYSTALLIZATION  IOI 

exactly  equal  amounts  at  any  point  m  £he  -crystallization,  for 
if  at  any  time  the  whole  mass  of  crystals  -be  -removed  and  dis- 
solved in  water  the  solution  will  be  foutid  to  -have  no  rotating 
power,  and  the  mother-liquor  likewise  not.  The  two  salts 
must  therefore  possess  exactly  the  same  solubility.  Jung- 
fleisch,  on  the  contrary,  believes1  that  the  right  salt  is  less 
soluble  than  the  left,  inasmuch  as  he  found  more  of  the  first 
in  the  early  part  of  the  crystallization,  and  more  of  the  second 
in  the  last  part. 

The  separation  of  the  two  tartrates  may  be  accomplished  as 
Gernez2  found,  in  this  way:  The  original  solution  prepared  by 
heat  is  carefully  kept  free  from  crystals  of  the  salt  or  from 
dust  and  allowed  to  cool  down  until  it  reaches  the  super- 
saturated condition,  wrhen  a  few  crystals  of  the  d-  or  /-sodium 
ammonium  tartrate  are  throwrn  in.  Then  the  separation  of  the 
corresponding  salt  follows,  while  the  other  remains  in  solution. 

Besides  racemic  acid  the  following  racemic  bodies  have  been 
resolved  by  crystallization: 

r- Fermentation  lactic  acid,  in  the  form  of  its  zinc-ammonium 
salt,  ZnNH4(C3H5O3)3  -f-  3H2O,  which  breaks  down  into  the 
d-  and  /-  lactates,  ZnNH4(C3H5O3)3  +  2H2O  (Purdie.)3  This 
takes  place  when  to  a  concentrated  solution  of  the  racemic 
compound,  brought  to  supersaturation  by  cooling,  crystal  frag- 
ments of  one  of  the  lactates  are  added,  which  brings  about  a 
separation  of  the  corresponding  salt.  The  crystal  fragments 
needed  for  this  are  prepared  by  splitting  the  r-lactic  acid  by 
means  of  the  more  easily  performed  strychnine  method.  If 
the  solution  of  the  r-zinc-ammonium  salt  alone  be  allowed  to 
crystallize  spontaneously  at  the  ordinary  temperature  most  of 
the  salt  separates  as  such. 

Solutions  of  the  following  four  compounds  furnish 
simultaneously  crystals  of  the  d-  and  /-modifications,  which 
can  be  distinguished  crystallographically,  when  their  aqueous 
solutions  are  allowed  to  evaporate  at  the  ordinary  temperature. 

dl-Gulonic  acid  lactone,  formed  by  mixing  the  antipodes 
(Fischer  and  Curtiss).4  Racemic  crystals  are  not  formed. 

i  Jungfleisch:  Bull.  Soc.  Chim.  [2],  41,  226. 
-  Gernez:  Cotnpt.  rend.,  63,  843. 

3  Purdie:  J.  Chem.  Soc.,  63,  1144  to  1151. 

4  Fischer  and  Curtis  :  Ber.  d.  chem.  Ges.,  25,  1046. 


102  RESOLUTION   OF   RACEMIC    BODIES 


by,  auction  of  ammonia  on  esters  of  maleic  and 
fumaric  Qcid  .(Korner  and  Menozzi),1  or  from  the  antipodes 
(Piutti).-'  Racemic  crystals  are  not  formed  under  the  same 
conditions. 

r-Homoaspartic  acid,  formed  by  the  action  of  alcoholic 
ammonia  on  the  ethyl  esters  of  citra-,  mesa-  and  itaconic  acids 
(Korner  and  Menozzi  )t? 

r-GIutaminic  rtf/V/fromr-glutamide  (Menozzi  and  Appiani).4 
The  holohedric  crystals  of  the  r-acid  on  repeated  crystallization 
from  water  yield  crystals  with  right-  and  left-hemihedral  sur- 
faces. 

2  .  Resolution  by  Active  Compounds 

33-  This  method  is  based,  as  explained  in  §  18,  on  the  un- 
equal solubilities  shown  by  the  salts  of  a  d-  and  /-acid  with 
the  same  active  base  (alkaloid),  or  of  a  d-  or  /-base  with  the 
same  acid  {e.g.  tartaric  acid).  It  was  first  applied  by  Pasteur5 
in  the  decomposition  of  racemic  acid,  by  which  he  found  that 
when  a  hot  aqueous  solution  of  the  acid  was  mixed  with 
molecular  proportions  of  different  cinchona  bases  to  saturation 
there  separated  on  cooling,  not  the  racemic  acid,  but  the  tartaric 
acid  salt  ;  with  quinine  or  quinicine  the  first  crystallization  con- 
tained </-  tartaric  acid,  but  /-tartaric  acid,  on  the  contrary, 
with  cinchonine  or  cinchonicine.  Later  the  method  was 
applied  to  the  resolution  of  many  other  racemic  acids,  and  of 
these,  first  to  malic  acid  by  Bremer6  in  1880.  Then  it  was 
used  with  bases,  and  first  with  synthetic  conine  whose  resolu- 
tion was  carried  out  by  Ladenburg7  in  1886  by  means  of  d- 
tartaric  acid.  The  process,  which  has  already  rendered  good 
service  in  many  instances,  aids  especially  in  the  separation  of 
the  component  in  the  less  soluble  salt  in  pure  condition,  while 
on  the  other  hand,  the  purification  of  the  component  remain- 
ing in  the  mother-liquor  offers,  frequently,  considerable  diffi- 
culty, as  it  cannot  be  easily  separated  from  the  first.  But  in 

Korner  and  Menozzi  :  Ber.  d.  chem.  Ges.,  ai,  Ref.  87. 

I'iutti  :  Ibid.,  19,  1694. 

Korner  and  Menozzi  :  Ibid.,  27,  Ref.  121. 

Menozzi  and  Appiani  :  Ibid.,  24,  Ref.  399  :  27,  Ref.  121. 

Pasteur-  Compt.  rend.,  36,  197;  37,  162;  Ann.  chiin.  phys.  [3],  38,  437. 

Bremer:  Ber.  d.  chem.  Ges.,  13,  352. 

I,adenburg:  Ibid.,  19,  2582. 


BY   ALKALOIDS  103 

most  cases,   it  is  a  question  of  securing  one  of  the  antipodes 
only,  the  second  being  obtainable  in  some  other  way. 

a.  Resolution  of  Racemic  Adds  by  Aid  of  Alkaloid 

As  remarked  in  §18,  the  alkaloids  exhibit  no  regular 
behavior  with  respect  to  which  one  of  the  optical  modifications 
of  an  acid  they  unite  with,  to  form  the  less  soluble  salt;  the 
same  base  precipitates  the  d-salt  of  one  acid,  and  the  /-salt  of 
another.  But  in  the  case  of  the  cinchona  bases,  the  rule 
appears  to  obtain,  that  if  those  of  the  formula  C19H22N2O 
(cinchonine,  cinchonidine,  cinchonicine)  precipitate  the 
/-modification,  then  those  of  the  formula  C20H24N2O2  (quinine, 
quinicine,  quinidine)  yield  the  less  soluble  salt  with  the 
^-modification.  In  general,  by  preliminary  tests,  it  is  neces- 
sary to  find  the  most  suitable  alkaloid,  that  is,  the  one  which 
yields  well  crystallizable  salts  with  the  acid  in  question. 

At  present,  in  the  splitting  of  the  acids,  the  following 
alkaloids,  which  are  all  monacid  bases,  are  most  commonly 
employed  : 

Cinchonine. — Crystallized  :  C19H22N2O  ===  294.  Dextrorota- 
tory. Difficultly  soluble  in  cold  or  warm  water.  Soluble  at 
20°  in  126  parts  of  alcohol  of  84  per  cent,  by  volume. 

Cinchonidine. — Crystallized  :  C19H22N2O  =  294.  Levorotatory. 
At  10°  soluble  in  1680  parts  of  water  or  in  19.7  parts  of  80 
per  cent,  alcohol  by  volume. 

Quinine.—  Crystallized  :  C20H24N2O2  +  3H2O  =  378.  Levo- 
rotatory,  soluble  in  773  parts  of  boiling  water  and  in  1.13 
parts  of  absolute  alcohol  at  20°. 

Quinidine.—  Crystallized  :  C20H24N2O2  -f  24-  H2O  =  =  369. 
Effloresced:  C20H24N2O2  -f  2H2O  =  360.  Dextrorotatory. 
Soluble  in  750  parts  of  boiling  water  and  in  26  parts  of  80 
volume  per  cent,  alcohol  at  20°. 

Strychnine. — Crystallized:  C21H22N2O2  —  334.  Levorotatory. 
Soluble  in  2,500  parts  of  boiling  water.  Insoluble  in  absolute 
alcohol.  Soluble  in  120  parts  of  cold  or  in  10  parts  of  boiling 
alcohol  of  80  volume  per  cent. 

Brucine.— Crystallized:  C23H26N2O4  -f  4H2O  =  446.  Levo- 
rotatory. Soluble  in  150  parts  of  boiling  water,  easily  soluble 
in  alcohol. 


104  RESOLUTION   OF   RACEMIC    BODIES 

Morphine.— Crystallized:  C17H]9NO3  -f  H2O  =  303.  Levo- 
rotatory.  Difficultly  soluble  in  cold,  readily  soluble  in  hot 
water.  Soluble  in  40  parts  of  cold  or  in  30  parts  of  boiling 
absolute  alcohol. 

The  alkaloids  and  racemic  acids,  the  latter  taken  with  the 
simple  molecular  weight,  have  been  usually  combined  in  the 
molecular  proportions  of  i :  i .  With  the  monobasic  acids  the 
neutral  salts  are  formed,  and  with  the  dibasic  acids,  acid  salts, 
which  have  the  advantage  of  easier  crystallization.  In  some 
cases  (as  racemic  acid,  cinnamic  acid  dibromide)  it  has  been 
found  advantageous  to  take  2  molecules  of  acid  to  i  of  the 
base,  which  leaves  half  of  the  acid  and  in  form  of  one  of  the 
antipodes,  mainly  in  uncombined  condition. 

The  crystallization  of  the  less  soluble  salt  and  its  separation 
from  the  more  soluble  one,  is  accomplished  in  several  ways, 
depending  on  the  nature  of  the  substances  :  (i)  By  cooling 
the  hot  saturated  solution;  (2)  By  slow  evaporation  of  the 
solution  at  the  ordinary  temperature  and  fractional  crystal- 
lization; (3)  By  adding  a  crystal  of  the  less  soluble  salt  to 
the  strongly  concentrated  or  supersaturated  solution  (sowing, 
inoculation).  It  has  been  found  here,  that  crystals  may  be 
used,  which  do  not  contain  the  modification  of  the  acid  to  be 
separated,  but  the  one  with  opposite  rotation.  For  example, 
the  addition  of  a  crystal  of  /-cinchonine  malate  to  a  solution  of 
racemic  cinchonine  malate  causes  a  separation  of  the  a^-salt, 
a  phenomenon  which  Bremer1  has  explained  from  the  obser- 
vations of  Groth2  on  quartz,  sodium  chlorate,  and  sodium 
periodate,  to  depend  on  the  tendency  shown  by  enantio- 
morphous  crystals  to  form  twins  consisting  of  the  oppositely 
rotating  varieties. 

Below  is  given  a  resume  of  the  racemic  acids  which  have 
been  split  by  the  aid  of  alkaloids,  along  with  a  discussion  of 
the  most  important  observations  made  in  the  experiments. 

Racemic  acid,  as  is  well  known,  was  first  broken  up  by 
Pasteur  with  initial  separation  of  : 

1  Bremer:  Ber.  d.  chem.  Ges.,  13,  352. 

2  Groth  :  Pogg.  Ann.,  138,  214. 


BY    ALKALOIDS  105 

Proportions  used. 
Base.  Acid. 

a.  The  /-tartrate 

By  cinchonine  from  alcoholic  solution1 i         : 

cinchonicine  from  aqueous  solution- i         : 

b.  The  rf-tartrate 

By  quinine  from  alcoholic  solution1 i         : 

quinicine  from  aqueous  solution2 i         : 

brucine  from  alcoholic  solution1 J 

I      2        : 

For  the  separation  of  the  /-acid,  which  is  always  the  desired 
product,  cinchonine  serves  best  and  may  be  used  with  advan- 
tage in  the  manner  suggested  by  Marckwald3  in  w^hich  for  2 
mols  of  C4H6O6  -  -  300.  i  mol  of  C19H22N.,O  =  -  294,  that  is 
about  equal  weights  of  each,  is  taken.  To  the  boiling  aqueous 
solution  of  the  racemic  acid  the  cinchonine  is  added  in  small 
portions,  and  enough  wrater  then  to  maintain  a  clear  solution. 
On  cooling  /-cinchonine  tartrate  crystallizes  out,  and  after 
standing  a  day,  may  be  filtered  off.  The  yield  is  about  two- 
thirds  of  the  theoretical.  After  a  second  crystallization  from 
hot  water  the  salt  is  decomposed  by  ammonia,  and  from  the 
solution  separated  from  the  cinchonine  by  filtration  the  /-tar- 
taric  acid  is  thrown  down  b}'  lead  acetate.  The  lead  salt  is 
decomposed  by  hydrogen  sulphide,  or  with  larger  amount, 
better  by  dilute  sulphuric  acid  for  recovery  of  the  free  acid. 
From  the  mother-liquor  of  the  /-cinchonine  tartrate,  which 
contains  mainly  the  free  ^/-acid  along  with  small  amounts  of 
the  /-acid  and  the  cinchonine  salts  of  both,  crystals  of  acid  d- 
cinchonine  tartrate  separate  after  a  time  and  can  be  wrorked 
up  for  recovery  of  the  base.  The  liquid  filtered  from  these  is 
divided  into  two  halves,  one  of  which  is  exactly  saturated  with 
soda  and  the  other  with  ammonia,  and  after  filtration  of  the 
separated  cinchonine,  these  are  united  and  concentrated  by 
evaporation.  After  cooling  ^/-sodium  ammonium  tartrate 
crystallizes  first.  The  mother-liquor  is  then  allowed  to  evap- 
orate until  a  portion  tested  in  the  polariscope  is  found  to  be 
inactive  or  slightly  levorotatory.  The  racemate  is  now  pres- 
ent which  can  be  converted  into  free  acid  and  treated  anew 
with  cinchonine. 

1  Pasteur:  Ann.  chim.  phys.,  [3],  38,  437. 

2  Pasteur:  Compt.  rend.,  37,  162. 

3  Marckwald:  Ber.  d.  chem.  Ges.,  29,  42. 


106  RESOLUTION   OF   RACEMIC   BODIES 

Malic  acid. — The  r-acid  obtained  by  reduction  of  racemic 
acid  by  means  of  hydriodic  acid,  was  converted  by  Bremer1  into 
the  acid  cinchonine  salt,  and  to  the  concentrated  solution  a  crys- 
tal of  the  acid  cinchonine  salt  of  common  malic  acid  from 
mountain-ash  berries  was  added.  Crystallization  followed,  and 
after  conversion  into  acid  ammonium  malate  furnished  this  salt 
in  the  right-hand  modification.  As  the  corresponding  salt  of 
ordinary  malic  acid  is  levorotating  in  all  concentrations,'2  this 
shows  the  production  of  the  antipode.  From  the  mother- 
liquor  of  the  ^-cinchonine  malate,  the  ordinary  /-acid  ammo- 
nium malate  could  be  obtained,  but  not  in  pure  condition. 

Methoxysucdnic  acid,  CO2H— CH(O.CH3)— CH2— CO2H.- 
a,  with  cinchmiine,  i  :  I,  in  aqueous  solution  evaporated  over 
sulphuric  acids  yields  first  crystals  of  the  acid  ^-salt,  and  from 
the  mother-liquor,  the  /-salt.  Both  antipodes  are  obtained 
pure  (Purdie,  Marshall  and  Bolam).3 

b,  with  strychnine,  i  :  i  in  water.  The  /-salt  is  somewhat  less 
soluble.  The  concentrated  supersaturated  solution  was  treated 
with  a  crystal  of  the  /-salt,  which  caused  separations  of  the 
corresponding  compounds.  Both  antipodes  were  obtained 
pure  (Purdie  and  Bolam).4 

Ethoxysuccinic  acid  with  cinchonidine ,  i  :  i.  Crystals  of  the 
af-salt  separate  first  on  cooling  the  hot  aqueous  solution 
(Purdie  and  Walker).5 

Isopropoxysuccinic  add  with  strychnine.  With  the  base  and 
acid  in  proportion,  2:1,  the  neutral  /-salt  crystallizes  first,  and 
then  the  ^-salt.  With  i  :  i  the  acid  /-salt  separates  first, 
while  the  af-salt  forms  an  uncrystallizable  sirup,  which  can  be 
brought  to  crystallization  by  conversion  into  the  neutral  salt. 
Both  antipodes  are  pure  (Purdie  and  Bolam).6 

Pyrotartaric  acid  with  strychnine,  i  :  i .  By  evaporation  of 
the  aqueous  solution,  the  </-salt  separates  first.  By  repeated 
crystallization,  separation  of  the  acid  and  reconversion  into 

Bremer:  Ber.  d.  chem.  Ges.,  13,  351. 

Sec  Schneider  :  Ann.  Chem.  (I<iebig),  207,  274. 

Purdie  and  Marshall :  J.  Chem.  Soc.,  63,  217  ;    Purdie  and  Bolam  :  \Ibid.,  67,  944. 

Purdie  and  Bolam  ;  Ibid.,  67,  946. 

Purdie  and  Walker  :  Ibid.,  63,  236. 

Purdie  and  Bolam  :  Ibid.,  67,  952. 


BY    ALKALOIDS  107 

the  strychnine  salt,  the  ^-acid  was  obtained  in  pure  condition, 
but  not  the  /-acid   (Ladenburg).1 

Lactic  acid  with  strychnine,  i  :  i .  The  aqueous  solution  sub- 
jected to  fractional  crystallization  gave,  at  first,  products  which 
on  conversion  into  the  ammonium  or  zinc  salt  yielded  these  in 
the  right-rotating  form,  that  is,  they  contained  the  /-acid.  From 
the  last  crystallizations,  the  ^-acid  (salts,  levorotatory)  was 
obtained.  By  repeated  crystallization  of  the  strychnine  salts, 
both  antipodes  were  obtained  pure  (Purdie  and  Walker).2 

a-Oxybutyric  acid,  CH3.CH2.CHOH.CO,H,  with  brucine, 
The  salt  of  the  /-acid  crystallizes  first  (Guye  and  Jordon).3 

Valeric  acid,  CH3— CH2— *CH.CH3— CO2H,  (from  ethyl- 
methyl  malonic  acid)  with  brucine  i  :  i.  On  cooling  the 
solution  prepared  by  the  aid  of  heat,  the  /-salt  .separates  first. 

By  oft-repeated  recrystallization  of  the  less  soluble  fractions, 
(/-salt)  the  rotation  of  the  liberated  acid  was  brought  up  to  a 
maximum  (\_a]D=  —17.85°).  The  ^/-acid  could  not  be 
obtained  in  the  same  strength.  The  reason  for  the  difficult 
separation  is  found  in  the  fact,  that  d-,  /-,  and  r-brucine 
valerate  are  isomorphous  with  each  other.  The  crystals  are 
monoclinic  hemimorphous  (Schiitz  and  Marckwald).4 

Galactonic  acid  with  strychnine. — The  lactone  of  the  r-acid 
is  dissolved  in  70  per  cent,  alcohol  and  boiled  with  an  excess 
of  finely  powdered  strychnine.  The  filtrate  is  evaporated 
after  addition  of  water,  which  throws  out  part  of  the  base,  to 
the  condition  of  a  thin  sirup.  On  cooling,  fine  needles 
crystallize  which  consist  largely  of  the  af-salt;  the  same  is  true 
of  the  second  crystallization.  The  mother-liquor  contains  the 
/-salt.  Both  antipodes  are  secured  by  repeated  recrystallizations 
of  the  strychnine  salts.  The  lactone  of  the  */-acid  rotates 
strongly  to  the  left,  that  of  the  /-acid  to  the  right  (Fischer).5 

Mannonic  acid  with  morphine. — From  the  solution  obtained 
by  boiling  the  r-acid  with  morphine  the  ^-salt,  after  evapo- 
rating to  a  sirup,  is  separated  in  the  form  of  crystals  which  are 

1  lyadenburg  :  Ber.  d.  chern.  Ges.,  28,  1170. 
-  Purdie  and  Walker  :  J.  Chem.  Soc.,  61,  757. 

3  Guye  and  Jordon  :  Compt.  rend.,  120,  562. 

4  Schiitz  and  Marckwald  :  Ber.  d.  chem.  Ges.,  29,  52. 

5  E.  Fischer:  Ibid.,  25,  1256. 


108  RESOLUTION   OF    RACEMIC    BODIES 

freed  from  mother-liquor  by  washing  with  methyl  alcohol. 
The  </-salt  only  may  be  obtained  pure  (Fischer).1 

Mandelic  acid  with  cinchonine,  i  :  i .  This  is  dissolved  in 
boiling  water,  and  after  cooling  a  crystal  of  the  </-saltis  added, 
and  the  liquid  allowed  to  evaporate.  The  yield  of  the  </-salt 
is  about  80  per  cent,  of  the  theoretical.  After  evaporation 
and  long  standing,  the  mother-liquor  deposits  crystals  of  the 
/-salt.  The  </-acid  may  be  obtained  pure,  but  the  /-acid  is 
best  made  from  the  amygdalin  (Lewkowitsch).2 

Tropic  acid,  C6H5.*CH.CH2OH.CO2H,  with  quinine  in. 
If  the  base,  dissolved  in  dilute  alcohol,  be  added  to  a  hot 
aqueous  solution  of  the  acid,  and  the  mixture  evaporated  at 
100°,  to  beginning  crystallization,  the  af-salt  separates  in  pure 
white  crystals.  The  mother-liquor  on  further  concentration 
leaves  an  oil  which  gradually  solidifies  to  glassy  crystals  of 
the  /-salt.  Both  salts  may  be  purified  by  recrystallization. 
For  the  </-acid,  [or]/,  =  -f-  71  ° ;  the  /-acid  could  not  be  obtained 
pure  (Ladenburg  and  Hundt).3 

Phenyl-ctfi-dibrompropionic  acid  (cinnamic  acid  dibromide), 
C6H5.*CHBr.*CHBr.CO2H.  From  the  r-compound  the  follow- 
ing difficultly  soluble  salts  were  separated: 


With   cinchonine, 
"     cinchonidine, 
"     quinidine, 
"     strychnine, 
"     strychnine, 
"     brucine, 


base  :  2  acid,  from  alcohol  solution  the  /-acid4 
"      :  i     "         "     benzene       "  "   /-acid5 

"      :   i     "         "      alcohol        "          "  tf-acid5 
"      :  i     "         "         "  "          "   /-acid6 

«      :  2     "         «         «  «          .. 


2 


With  strychnine  and  2  molecules  of  acid  the  neutral  salt, 
C21H22N2O2.C9HHBr,O,,  is  always  precipitated. 

The  separation  of  the  pure  antipodes  which  was  undertaken 
by  Liebermann8  by  the  strychnine  method  is  difficult.  It  is  best 
to  proceed  in  this  way:  Dissolve  20  grams  (2  mols)  of  the 
cinnamic  acid  dibromide  in  400  cc.  of  absolute  alcohol  and  add 

Fischer:  Ber.  d.  chem.  Ges.,  23,  379. 

I^cwkowitsch  :  Ibid.,  16,  1573. 

Ladenburg  and  Hundt:    Ibid.,  aa,  2590. 

Erlenmeyer,  Jr.:  Ibid.,  36,   1659;  Hirsch  :  Ibid.,  27,887. 

Hirsch:  Ibid.,  37,  888. 

I,.  Meyer,  Jr.:  Ibid.,  35,  3121;  Liebermann  :  Ibid.,  26,  247. 

Hirsch:  Ibid.,  27,  887. 

Liebermann:  Ibid.,  26,  247  and  829. 


BY    ALKALOIDS  1 09 

then  ii  grams  (i  mol)  of  strychnine  as  follows:  Dissolve  the 
alkaloid  by  aid  of  heat  in  an  excess  of  hydrochloric  acid  and 
while  still  hot  add  excess  of  ammonia,  which  yields  a  crystal- 
line easily  filtered  precipitate.  This  is  washed  with  a  little 
water  and  alcohol,  and  then,  after  puncturing  the  filter-paper, 
is  washed  into  the  cinnamic  acid  solution  by  the  aid  of  220  cc. 
of  absolute  alcohol.  After  solution  is  effected  by  aid  of  heat, 
the  mixture  is  allowed  to  stand  about  twenty  hours,  in  which 
time  20  to  25  per  cent,  of  the  acid  separates  as  strychnine  salt 
of  the  ^-form.  (With  i  molecule  of  base  to  i  of  acid  the  /- 
form  separates  first.)  For  separation  of  the  free  acid  the  salt 
is  suspended  in  wrater,  acidified  with  hydrochloric  acid  and 
shaken  with  ether,  and  the  ethereal  solution,  after  a  second 
shaking  with  water,  evaporated.  The  highest  observed  rota- 
tion amounts  to  [<*]/>  =  4-  68.3  for  12  to  15  per  cent,  solution 
in  alcohol.  From  the  mother-liquor,  after  a  second  treatment 
writh  strychnine  (i  of  base  :  2  of  acid),  more  of  the  d-sa\t  and 
then  the  salt  of  the  /-acid  may  be  obtained.  The  latter  acid 
has  been  secured,  however,  with  rotation  up  to  [<*]/>  = 
45.8°  only. 

Allocinnamic  acid  dibromide  could  be  separated  by  aid  of 
cinchonidine  in  benzene  solution  from  which  the  salt  of  the 
/-acid  crystallized.  The  highest  observed  polarization  of  the 
acid  was  [<*]/?=  -83.2°.  The  af-acid  could  not  be  obtained 
pure  (Liebermann1). 

Phenyl-a  fi-dichlorpropionic  acid,  (cinnamic  acid  dichloride) 
with  strychnine,  i  molecule  of  base,  (40  grams)  and  i  molecule 
of  acid  (45  grams),  dissolved  in  500  cc.  of  99.5  per  cent,  alcohol 
gave  crystals  of  the  </-salt  after  standing  40  hours.  By 
separating  the  acid  from  the  crystals,  and  treating  again  with 
strychnine,  the  ^-acid  was  directly  secured  with  maximum 
rotation.  The  mother-liquors  from  the  first  separation,  after 
four  treatments  with  strychnine,  furnished  the  pure  /-acid 
(Liebermann  and  Finkenbeiner).2 

Phenyldibrombutyric  acid  (phenylisocrotonic  acid  dibromide) , 
C6H5.*CHBr.*CHBr.CH2.CO2H,  with  brucine,  i  :  i.  From 
the  alcoholic  solution,  the  af-salt  separates  on  standing,  the 

1  Liebermann  :  Ber.  d.  chein.  Ges.,  27,  2041. 

-  L,ieberman  and  Finkbeiner  :  Ber.  d.  chem.  Ges.,  26,  883  ;  27,  889. 


I  10  RESOLUTION   OF    RACEMIC    BODIES 

crystallization  being  induced  by  rubbing  with  a  glass  rod. 
The  yield  is  about  three-fourths  of  the  theoretical.  By 
extracting  the  salt  with  enough  hot  alcohol  to  leave  about 
one- third  undissolved,  it  may  be  obtained  in  quite  pure 
condition.  On  evaporating  the  mother-liquor  to  dryness,  the 
/-salt  separates,  partly  crystalline.  With  the  proportion 
of  i  molecule  of  base  to  2  of  acid,  a  small  amount  of  the 
</-salt  separates,  but  in  purer  form  (L.  Meyer  and  Stein).1 

Phenyl-a-bromlacticacid,  C6H5.*CHOH.*CHBr.CO2H  -f  H2O 
with  cinchonine.  The  df-salt  crystallizes  in  white  needles  from 
the  solution  in  absolute  alcohol  ;  the  much  more  soluble 
/-salt  is  obtained  as  a  sirup  which  finally  solidifies  to  a  horny 
mass  (Erlenmeyer,  Jr.).2 

hopropylphenylglycolic  add,  C6H4.C.,H7.*CHOH.CO2H,  with 
quinine  and  cinchonine.  If  one  molecule  of  quinine  and  one  of 
the  acid  be  dissolved  in  hot  alcohol,  and  then  treated  with  hot 
water,  and  allowed  to  cool,  the  /-quinine  salt  separates.  The 
acid  is  liberated  from  the  mother-liquor  and  combined  in  hot 
aqueous  solution  with  cinchonine.  On  cooling,  the  cinchonine 
salt  of  the  */-acid  separates  first  (Fileti).3 

CH— CH2— *CH— C02H 

Dihydro-o-phthalic  acid,  ,  with  strych- 

CH— CH  =  C— CO2H 

nine,  i  :  i.  In  fractional  crystallization,  the  d-sa\t  separates 
first  from  aqueous  solution  (Proost).4 

b.  Resolution  of  Raccmic  Bases  by  Tartaric  Acid. 

This  method,  first  applied  by  Ladenburg'  for  the  breaking 
up  of  synthetic  conine,  has  been  carried  out  by  converting 
the  racemic  base  by  treatment  with  ordinary  ^-tartaric  acid 
into  a  mixture  of  the  bitartrates  of  the  d-  and  /-bases  and 
separating  these  by  fractional  crystallization.  In  this  way  it 
was  possible  to  obtain  more  or  less  readily  that  modification  in 
pure  form  which  was  contained  in  the  less  soluble  salt,  while, 
on  the  contrary,  the  other  was  always  obtained  in  a  condition 
with  much  lower  rotation.  In  order  to  obtain  the  latter  also 

I,.  Meyer  and  Stein  :  Ber.  d.  chem.  Ges.,  37,  890. 

Erlenmeyer,  Jr.  :  Ann.  Chem.  (Uebig),  371,  159 :  Ber.  d.  chem.  Ges.,  34,  2830. 

Fileti  :  Gazz.  chim.  ital.,  33,  II,  395;  Ber.  d.  chem.  Ges.,  36,  Ref.  89. 

Proost ;  Ber.  d.  chem.  Ges.,  37,  3185. 

Ladenburg:  Ibid..  19,  2582. 


BY   TARTARIC    ACID  III 

in  a  pure  state,  Marckwald1  suggested  that  the  mother-liquors 
from  the  precipitation  with  ^-tartaric  acid  be  decomposed  with 
separation  of  the  base  and  that  this  by  addition  of  /-tartaric 
acid  be  converted  into  the  /-bitartrate,  which  salt  is  now  the 
more  readily  crystallizable.  In  this  way  the  separation  of  the 
antipodes  is  complete.  Other  active  acids  than  tartaric  have 
not  been  tried  as  yet. 

The  following  racemic  bases  have  been  split: 
/CH, CH.CH3 

a-Pipecoline,    CH0<  \VTT  By    saturation  of  the 

•\CH2-CH./^ 

racemic  base  with  one  molecule  of  tartaric  acid  in  aqueous  solu- 
tion, evaporation  to  a  sirup  and  addition  of  a  minute  crystal 
of  ^/-conine-^-bitartrate  Ladenburg2  obtained  the  salt  of  the  d- 
base  as  a  white  tallow-like  mass,  while  the  /-base  remained  in 
the  liquid  pressed  out.  After  repeated  crystallization  of  the 
solid  salt  pure  d-  pipecoline  could  be  separated  by  distillation 
with  caustic  soda  (an  =  31.9°  for  i  dm. ) ;  the  /-base  could  not 
be  isolated.  Marckwald3  added  to  the  sirup  of  the  ^/-bitartrate 
of  the  racemic  base  crystals  of  r-pipecoline  racemate 
(C6H13N.C4H6O6  -f-  H2O,  monoclinic)  by  which  crystallization 
of  </-pipecoline-</-bitartrate  (C6H13N.C4H6O6  -f  2H2O,  mono- 
clinic,  hemimorphous)  was  induced.  This  phenomenon  is 
singular  as  the  two  salts  are  different  with  respect  to  crystal- 
line form  and  amount  of  water.  By  rubbing  the  crystal 
magma  with  a  little  water,  draining  with  the  pump,  dissolving 
in  a  little  hot  water  (about  4  cc.  to  10  grams  of  salt)  and  cool- 
ing the  d-d  salt  was  obtained  perfectly  pure.  After  separating 
a  further  small  amount  of  crystallizable  substance  from  the 
mother-liquor,  the  separated  sirup  was  distilled  with  caustic 
soda  and  the  collected  mixture  of  a  small  amount  of  the  af-base 
with  much  of  the  /-base  was  converted  into  bitartrate  by  the 
addition  of  /-tartaric  acid.  Crystals  of  /-pipecoline-/-bitartrate 
now  separated.  By  again  separating  the  bases  from  the 
mother-liquor  and  treating  first  with  the  d-  and  then  with 
/-tartaric  acid  a  nearly  quantitative  separation  of  the  r-pipeco- 
line  into  the  active  forms  (aD  —  ±  32°  for  i  dm. )  was  reached. 

i  Marckwald;  Ber.  d.  chem.  Ges.,  39,  43. 
-  I,adenburg:  Ann.  Chem.  (L,iebig),  24y,  65. 
;  Marckwald:  Ber.  d.  chem.  Ges.,  29,  43. 


112  RESOLUTION   OF    RACEMIC    BODIES 

fi-Pipecoline. — The  solution  of  the  bitartrate  evaporated  on 
the  water-bath,  yields  racemic  crystals,  but  by  slow  evapo- 
ration in  the  cold,  crystals  of  the  /-base  are  formed.  The 
af-base  was  not  secured  (Ladenburg).1 

/CH2  —  *C.H.C.,H5 

a-Ethylpiperidine,  CH./  >NH         — By    the  aid    of 

X^H2 — CH2 

af-tartaric  acid,  the  af-base  may  be  obtained  pure  (Ladenburg).'2 

/CH,-CH.C3H7 

a-N-Propylpiperidine,  CH./  >NH 

^CH2 — CH2 

Synthetic  conine. — This  was  obtained  by  Ladenburg3  from 
a-propylpiperidine  as  follows  :  To  the  concentrated,  but  not 
sirupy  solution  of  the  ^/-bitartrate,  small  crystals  of  the 
df-conine-df-bitartrate  were  added.  (These,  as  obtained  by 
Schorm4  from  natural  conine,  were  rhombic  crystals  having 
the  composition,  C8H15N.C4H6O6  -j-  2H2O.) 

A  crystal  magma  formed  from  which,  by  pressing  and 
recrystallizing,  the  debase  was  obtained  pure,  and  showing  the 
same  rotating  power  as  the  natural  conine,  [«]/>—+ 18.3°. 
It  is  also  possible  to  evaporate  the  moderately  dilute  solution 
of  the  tartrates  of  the  racemic  base  at  the  ordinary  temperature, 
and  then  purify  by  repeated  crystallization,  the  crystals  of 
d?-conine-</-bitartrate  wrhich  separate  first.5  The  /-form  was 
not  obtained  in  pure  condition. 

QJJ  *CH  CH 

Copellidine,  CH./  1N>NH. — By    evaporating   the 

\*CH.C2H5-CH/ 

aqueous  solution  of  the  tartrates,  the  salt  of  the  </-base 
crystallizes  first.  The  rotation  of  the  alkaloid  is  [<*]/?==  + 
36.5°  The  /-form  was  not  obtained  pure  (Levy  and  Wolff  en - 
stein)." 

Isocopellidine. — From  the  solution  of  the  bi tartrates,  the  salt 
of  the  /-base  crystallizes  first,  [<*]/>=  -25.9°.  The  d- base 
could  not  be  obtained  pure  (Levy  and  Wolffenstein). 

Propylenediamine,   CH3— *CH.NH2— CH2NHr—  One  mole- 

1  I,adenburg :  Ber.  d.  chem.  Ges.,  37,  75. 

2  leaden  burg :  Ann.  Chem.  (L,iebig),  247,  7'- 

3  I^adenberg :  Ber.  d.  chem.  Ges.,  19,  2582  ;  Ann.  Chem.  (i,iebig),  347,  ^5. 

4  Schorm :  Ber.  d.  chem.  Ges.,  14,  1768. 
6  L,adenburg  :  Ibid.,  37,  3065. 

•  Levy  and  WolfTenstein  :  Ibid.,  38,  2270. 


BY   STRONG   SULPHONIC    ACIDS  113 

cule  of  the  base  dissolved  in  water  with  two  molecules  of  tar- 
taric  acid  deposits  crystals  on  evaporating,  which  contain  the 
/-base,  [#]/?=  -20.96°. — The  </-base  was  not  obtained 
(Baumann).1 

xCH,— CH2 

Tetrahydroquinaldine,  CgH^  . — The    aqueous 

\NH-*CH.CH3 

solution  of  the  bitartrate  yields  monoclinic  hemimorphous 
crystals  of  the  salt  containing  the  </-base.  The  rotation  of  the 
base  is  [**]/>==  +  56°.  The  /-base  is  not  known  (Ladenburg).2 
[See  below.  Tr] . 

i,  5-Tetrahydronaphthylenediamine. — The  aqueous  solution 

H       NH.    °f  t^ie  ^-bitartrate,  evaporated  to  a  sirup,   and 

H    \/          treated    with   a    small     crystal    of   ^-conine- 

/\    */\  ^-bitartrate,    furnished    a  deposit  of  crystals 

HC       C       CH     which  held  the  /-base.     Rotation  of  the  salt 

I  I         la']z>  =  —  7-5°  fc>r/  =  3-96.     After  standing 

>v     xv      x     -    several  months,   the  separated  mother-liquor 

C       c  furnished    crystals   of    the   bitartrate  of   the 

XH,  H2  ^-base.     Rotation  of  this  salt :  [<*]  D  —  -f  8. 15° 

f or  p  =  2 . 44  °   ( Bamberger ) . 3 

a-Phenylethylamine,  C6H5*CH.CH,.NH2.— The  separation  as 
bitartrate  was  tried  first  by  Kraft,4  but  without  success,  and 
later  by  Loven5  who  succeeded.  The  concentrated  hot  solu- 
tion gave,  on  cooling,  needle-shaped  crystals  with  i|  H.,O,  from 
which  the  impure,  slightly  dextrorotatory  base  was  separated  ; 
from  the  mother-liquor  prismatic  anhydrous  crystals  slowly 
separated  which  furnished  a  strongly  left-rotating  base. 

c.   Resolution  by  Stronger  Acids 

Pope  and  Peachey6  have  recently  suggested  the  use  of  strong 
optically  active  acids  as  agents  of  resolution  in  place  of  tartaric 
acid,  ^-^-chlorcamphorsulphonic  acid,  ^-or-bromcamphorsul- 
phonic  acid  and  ^-camphorsulphonic  acid  are  compounds 
which  suffer  relatively  great  dissociation  in  aqueous  solution 

1  Baumann  :  Ber.  d.  chem.  Ges.,  28,  1179. 

2  Ladenburg  :  Ibid.,  27,  76. 

!  Bamberger  :  Ibid.,  23,  291. 
*  Kraft :  Ibid.,  23,  2783. 
''  IvOv£n  :  Ibid.,  29,  2313. 

0  Pope  and  Peachey:  J.  Chem.  Soc.,  73,  893  and  75,  1066. 
8 


114  RESOLUTION   OF   RACEMIC    BODIES 

and  in  their  action  with  weak  bases  may  be  compared  to  the 
mineral  acids.  Among  other  applications  the  following  may 
be  quoted: 

Tetrahydropapaverine,  C.20H.,5NO4. — By  combining  the 
racemic  base  in  aqueous  solution  with  the  calculated  amount 
of  */-ar-bromcamphor  sulphonic  acid  and  warming  to  effect  solu- 
tion the  combination,  C^H^NO^.C^I^BrO.HSOg,  is  formed. 
On  cooling  long  needles  of  the  /-salt  separate,  as  this  is  the 
less  soluble.  On  concentrating  and  cooling  again  more  of  the 
salt  may  be  secured.  For  the  purifiedcry  stals  [<*]/>  =  -  30° 
was  found.  In  the  mother-liquor  the  </-salt  is  left  but  could 
not  be  obtained  in  pure  crystalline  form. 

By  decomposing  the  /-salt  with  ammonia  the  /-base  is 
obtained  [<*]/>  =  -  143.4°.  From  the  resinous  df-salt  the  corre- 
sponding base  with  \<*\D  =  -  -j-  153.7°  was  secured  (chloroform). 

In  the  same  resolution  df-tf-chlorcamphorsulphonic  acid  was 
employed  also  with  good  results. 

The  authors  tried  Reychler's  camphorsulphonic  acid,  but 
the  salts  formed  remained  in  a  very  soluble  sirupy  form  and 
could  not  be  well  separated. 

Tetrahydroquinaldine,  C10H13N. — This  was  resolved  by  the 
aid  of  ^-a-bromcamphorsulphonic  acid  as  described  above. 
An  alcoholic  solution  of  the  /-salt  gave  \_<*\D  ='•  +  41  -5  °-  For 
the  base,  separated  by  distillation  in  a  current  of  steam  with 
a  slight  excess  of  soda,  [V]^  =  --  58.12  was  found. 

Camphoroxime ,  C,0H16.NOH. — The  racemic  oxime  was 
resolved  by  action  of  </-camphorsulphonic  acid.  Sixty  grams 
of  the  oxime  and  90  grams  of  the  sulphonic  acid  were  mixed 
in  boiling  acetone.  On  cooling  a  crystalline  precipitate  forms 
and  more  may  be  obtained  from  the  mother-liquor.  On 
recrystallizing  the  whole  of  the  fractions  from  boiling  ether 
two  products  are  finally  obtained,  the  less  soluble  being  </-cam- 
phoroxime  df-camphorsulphonate,  and  the  more  soluble  the 
/-camphoroxime  ^-camphorsulphonate.  For  the  first  [a]  7, 
-f-  4.3°  was  found  (c -~  1.7508  in  absolute  alcohol)  and  for 
the  oxime  from  it  \oi\D  -  -  41.3°.  The  oxime  from 
the  /-camphor  oxime  ^/-camphor  sulphonate  gave  [/*]/, 
+  41.7°. 


BY   ESTERIFICATION  115 

The  resolution  of  <*-benzylphenylallylmethyl  ammonium 
iodide  was  likewise  accomplished  by  aid  of  ^/-camphor  sulphonic 
acid1  (see  §  14)  and  very  recently  the  same  authors  have 
described  the  resolution  of  an  asymmetric  sulphur  compound 
by  use  of  this  optically  active  sulphonic  acid.2  This  compound 
is  methylethylthetine  and  from  the  bromide  by  addition  of  the 
silver  salt  of  ^-camphorsulphonic  acid  the  corresponding 
^-methylethylthetine  ^-carnphorsulphonate  was  obtained. 
This  has  the  composition: 


C,H5v       /CH2C02H' 
C10H15O.S03/     \CH3 


By  decomposing  the  alcoholic  solution  of  this  salt  by  addi- 
tion of  hydrochloric  acid  and  platinum  chloride,  the  platinum 
compound, 

C9H5          CH2CO,H 


.PtCl4, 

CK       \CH3 

is  obtained,   for  which  \_oi]D  -•  -\-  4.6°  was  found  (c  =  1.34, 
water). 

Resolution  by  Esterifi  cation  or  Saponification. 

The  processes  first  described  are  properly  physical,  as  no  real 
chemical  alteration  follows  in  the  combinations  to  produce 
new  crystalline  structures.  Essentially  different  in  principle 
is  a  method  recently  worked  out  by  Marckwald  and  McKenzie.3 

Two  optically  active  antipodes  must,  in  general,  exhibit  the 
same  behavior  in  all  chemical  reactions.  But  this  no  longer 
holds  if  the  reaction  takes  place  between  them  and  another 
asymmetric  compound.  If  the  change  in  question  is  one 
which,  like  the  formation  of  a  salt,  depends  simply  on  the 
affinity  of  acid  and  base,  no  difference  may  be  observed,  but  on 
the  other  hand,  a  difference  may  be  expected  in  proportion  as 
the  progress  or  direction  of  the  reaction  is  dependent  on  the 
space  relations  of  the  atoms  in  the  molecules  of  the  combining 
substances.  In  particularly  marked  degree,  the  formation  of 
esters  is  a  reaction  of  this  nature.  The  rapidity  of  esteri- 
fication  depends  to  a  remarkable  degree  on  the  structure  of  the 

1  J.  Chem.  Soc.,  75,  1127. 

2  Pope  and  Peachey:  Ibid.,  77,  1072. 

::  Marckwald  and  McKenzie  :  Ber.  d.  chem.  Ges.,  32,  2130  (1899). 


Il6  RESOLUTION   OF    RACEMIC    BODIES 

carbon  chain  of  the  acid.  The  velocity  of  esterification  for  the 
acids  of  the  type,  R.CH,CO2H,,  is  about  twice  as  great  as  for 
the  acids  of  the  type,  R'R".CH.CO,H,  and  much  greater  than 
for  the  acids,  R'R"R"'C.CO2H. 

These  relations  while  pronounced  in  the  aliphatic  acids  are 
more  clearly  marked  among  some  of  the  aromatic  acids,  a  fact 
which  was  pointed  out  by  v.  Meyer.1  It  would  appear 
probable,  therefore,  that  the  velocity  of  esterification  of  two 
oppositely  active  acids  with  the  same  optically  active  alcohol 
might  not  be  the  same.  This  question,  Marckwald  and 
McKenzie  tested  by  a  simple  experiment.  Equivalent  molec- 
ular amounts  of  racemic  mandelic  acid  and  menthol  were 
heated  for  an  hour  to  155°,  and  at  the  end  of  the  time,  the 
uncombined  acid  was  separated  from  the  reaction  product.  It 
was  found  to  be  left-rotating,  from  which  it  follows  that 
/-mandelic  acid  forms  an  ester  with /-menthol  more  slowly  than 
^-mandelic  acid. 

In  a  practical  experiment  50  grams  of  r-mandelic  acid  and 
50  grams  of  menthol  were  heated  to  155°  through  one  hour. 
In  the  reaction  mass  the  unchanged  acid  wras  separated  by 
dilute  ammonia,  and  finally,  after  separating  traces  of  the 
esters  and  menthol  with  it,  the  mandelic  acid  wras  precipitated 
by  sulphuric  acid.  The  recovered  acid  was  taken  up  com- 
pletely by  ether  and  after  evaporation  of  the  ether  was  found 
to  weigh  33.8  grams.  The  specific  rotation  was  found  to  be 
[a]/>  =  -  3.3°,  showing  that  it  now  contained  0.72  gram  of 
/-mandelic  acid.  In  the  paper  quoted,  the  authors  describe 
the  separation  and  identification  of  this  acid  in  pure  form. 

Experiments  were  then  made  with  the  mixture  of  esters 
and  unchanged  menthol  left  in  ether  solution  after  separation 
of  the  uncombined  mandelic  acid.  The  ether  was  evaporated, 
the  residue  mixed  with  3.5  grams  of  potassium  hydroxide  in 
solution  and  boiled  some  hours.  This  liquid  was  evaporated 
and  treated  with  water  to  dissolve  the  potassium  salt.  The 
solution  obtained  was  heated  to  drive  out  traces  of  menthol, 
treated  with  sulphuric  acid  and  extracted  with  ether.  In  this 
way  a  mandelic  acid  was  obtained  as  a  saponification  product, 
and  amounted  to  8. 7  grains  Its  specific  rotation  was  \_a]D  = 

1  v.  Meyer  :  Her.  d.  chem.  Ges.,  27,  i5<So;  28,  1254. 


BY    AID    OF    FUNGI  Iiy 

-f  3.  i°,  indicating  the  presence  o.  164  gram  of  the  ^-acid. 

The  remaining  menthyl  ester  was  treated  with  alcoholic 
potash  now  to  complete  saponification  and  the  mandelic  acid 
separated  as  before.  2.7  grams  were  obtained  and  this  had  a 
specific  rotation  of  [a]/,  =  -  10.4°,  corresponding  to  o.  188 
gram  of  /-mandelic  acid. 

The  authors  have  therefore  demonstrated  the  possibility  of 
resolution  by  their  general  processes.  They  point  out  further 
that  their  application  may  be  expected  in  the  resolution  of 
racemic  alcohols  rather  than  of  acids,  for  which  the  other 
methods  are  more  convenient. 

3.  Resolution  by  Aid  of  Fungi 

34.  As  already  mentioned  in  §  19  this  separation  depends  on 
the  phenomenon  that  when  in  solutions  of  racemic  bodies 
spores  of  certain  fungi  are  sowed  and  allowed  to  grow,  one 
of  the  antipodes  disappears  while  the  other  remains  untouched. 
Only  one  of  the  two  active  forms  is  thus  secured. 

A  number  of  general  observations  on  the  mode  of  action  of 
the  fungi  have  already  been  made.  In  this  place  we  are  con- 
cerned with  certain  matters,  which,  inasmuch  as  they  have 
received  but  little  consideration  in  the  chemical  literature,  call 
for  a  detailed  discussion. 

Data  on  the  Fungi  Suitable  for  Resolution.      Pure  Cultures  and 
Methods  of  Experimentation. 

BY  DR.  P.  LINDNER. 

Since,  by  aid  of  pure  culture  methods,  proof  has  been  given 
by  the  biological  work  of  the  last  decade,  that  the  mode  of 
development  of  most  of  the  lower  fungi  presents  a  certain 
constancy  and  is  by  no  means  as  complex  as  was  formerly  sup- 
posed, the  question  of  species  has  again  assumed  greater  im- 
portance and  interest.  The  mycologist  of  to-day  will  no 
longer  risk  designating  the  green  growth  on  a  piece  of  bread 
or  orange  peel  as  Penicillium  glaucum,  without  previously 
informing  himself  by  microscopic  examination  or  by  cultures. 
It  has  been  found  possible  to  establish  a  large  number  of 
species  which  have  the  green  color  of  the  spore  masses  in  com- 
mon, but  which  in  spite  of  apparent  macroscopic  similarity  in 


Il8  RESOLUTION   OF   RACEMIC    BODIES 

form    show    distinct    differences    from   a   morphological   and 
biological  standpoint. 

When  one  has  to  refer  to  data  in  the  older  literature  on 
Penicillium  glaucum  he  must  always  feel  uncertain  as  to 
whether  the  author  consulted  had  in  hand  the  organism  now 
so  designated  or  something  else. 

Also  the  statements  concerning  yeasts  in  the  older  literature 
must  to-day  be  received  with  caution.  Wine  yeast,  for 
example,  has  been  often  used  for  splitting  racemic  bodies. 
But  we  know  now  that  common  wine  yeast  may  be  a  mixture 
of  many  different  varieties.  If  some  one  of  these  should  be 
furnished  us  in  the  form  of  a  pure  culture  it  could  happen  that 
a  very  different  result  would  follow  from  a  splitting  experi- 
ment from  one  previously  recorded. 

In  view  then  of  our  advanced  knowledge  in  the  consideration  of 
the  fungi  the  task  of  studying  each  one  in  isolated  pure  form 
and  determining  its  action  on  nutritive  media  becomes  of  the  first 
importance. 

Scientific  aspirations  in  this  direction  are  greatly  advanced 
by  the  fortunate  circumstance  that  there  are  mycologic  insti- 
tutes like  that  of  Krai  (Prague,  Kleiner  Ring)  which  collect 
the  various  species  discovered  and  described  by  different 
authors,  make  pure  cultures  of  them  and  preserve  them  there 
for  sale. 

It  remains  then  for  the  experimenting  chemist  to  protect 
the  pure  culture,  as  received,  from  infection,  and  to  increase 
it  in  such  a  manner,  that  the  substance  to  be  investigated  may 
be  brought  completely  under  its  action.  It  will  be  explained 
below  how  all  this  may  be  most  conveniently  done. 

As,  however,  there  is  no  difficulty  in  securing  spores  of 
fungi  from  the  air  or  water,  and  bringing  them  into  the  con- 
dition of  pure  cultures,  one  may  often  proceed  to  a  certain 
degree  independently.  Care  should  be  taken  to  submit  finally 
a  portion  of  the  pure  culture  to  a  mycologist  for  exact  deter- 
mination of  species  before  publishing  the  results  of  investi- 
gations. 

How  may  the  spores  contained  in  the  air,  or  water,  or  other 
liquid  be  recognized  and  obtained  pure  ?  Suppose  we  wish  to 
examine  the  air  of  the  laboratory  for  fungi.  We  can  employ 


BY   AID   OF   FUNGI  1 19 

crystallization  dishes  or  glass  cylinders.  Two  dishes,  one  fit- 
ting over  the  other,  or  a  glass  cylinder  closed  with  a  plug  of  cot- 
ton, are  placed  in  the  oven  and  heated  two  hours  to  a  temperature 
of  about  150°  C.,  the  flame  under  the  oven  is  extinguished, 
and  the  glasses  are  allowed  to  cool  in  it.  When  this  is  accom- 
plished, we  allow  the  lowrer  dish  or  glass  cylinder  (such  a 
cylinder  as  is  used  with  a  specific  gravity  spindle)  to  stand 
open  one  to  tw7o  hours.  In  this  time  a  number  of  fungus 
spores  settle  from  the  air  onto  the  inner  glass  surfaces.  On 
account  of  their  minuteness,  these  are  not  visible  to  the  eye, 
and  because  of  their  relatively  small  number,  they  can  not 
be  found  by  a  strong  magnifying  glass  or  with  the 
microscope.  But  they  become  distinctly  visible  when  a  proper 
food  is  offered  them,  best  a  nutritive  gelatine.  Most  con- 
veniently beer- wort  gelatine  or  plum-decoction  gelatine  may  be 
prepared.  To  i  liter  of  beer- wort  or  plum-decoction  (each 
with  about  10  to  15  per  cent,  of  extract)  about  100  grams  of 
fine  white  gelatine  may  be  taken.  The  gelatine  mixture, 
prepared  by  dissolving  at  water-bath  heat  and  filtering,  is 
filled  into  test-tubes  which  are  plugged  with  cotton,  and  then 
exposed  to  steam  heat  one-half  hour(in  a  Koch's  sterilizer). 

The  contents  of  a  test-tube  is  poured  at  a  temperature  of 
20°  to  30°  C.,  into  the  exposed  glass  dish  or  cylinder.  The 
first,  with  its  cover  in  position,  after  the  hardening  of  the 
gelatine,  is  placed  in  a  moist  chamber,  that  is,  under  a  bell- 
jar,  the  air  in  which  is  kept  moist  by  wet  filter-paper  or 
by  equivalent  means.  The  gelatine  poured  into  the  glass 
cylinder  is  allowed  to  harden  around  the  sides,  which  may  be 
accomplished  by  holding  the  vessel  in  a  nearly  horizontal 
position  and  allowing  cold  hydrant  wrater  to  flow  over  it,  it 
being  meanwhile  slowly  rotated  to  effect  an  even  distribution. 
After  two  or  three  days  a  growth  begins  to  appear  everywhere 
in  the  gelatine  where  the  spores  lie  embedded,  and  this  later 
develops  to  a  branching  mycelium.  In  the  majority  of  cases, 
these  mycelia  are  pure,  t  that  is,  other  organisms  have  not 
grown  in  with  them.  Sufficient  indication  of  this  is  usually 
given  by  ocular  examination  alone.  The  term  'mycelium'  is 
applied  to  the  sum  of  the  threads  or  hyphae  growing  out  of 
the  fungus  spore.  While  some  of  these  play  the  part  of 


120 


RESOLUTION   OF    RACEMIC    BODIES 


rootlets,     others  grow  in  the  air   (so-called  air-hyphae)  and 
develop  to   fructification  (Fig.  6).     The  following  illustration 


*> 


Fig.  6.  Mucor  Mucedo. — Form  and  ramifications  of  a  full  grown  M rct'/non,  developed 
from  the  spore,  a.  fix  the  fruit  stem  and  s  the  sporangium.     After  Brefeld. 

gives  a  clear  representation  of  these  relations.  This  shows  a 
kind  of  mucor  Mucor  Mucedo},  which  may  be  easily  obtained 
from  bread,  malt,  horse-dung  and  decaying  fruits  kept  in  moist 


BY    AID    OF    FUNGI  121 

places.  At  a  is  shown  the  developed  spore  ;  /  is  an  air-hypha 
which  at  its  end  is  in  the  act  of  forming  a  spore-case  or 
so-called  sporangium.  With  darkening  in  this  spherical 
organ  maturity  is  reached.  If  we  touch  it  with  a  previously 
sterilized  needle,  the  sporangium  skin  breaks  and  a  large 
number  of  spores  cling  to  the  needle.  If  this  is  now  dipped 
into  sterile  nutritive  solution,  a  new  development  of  spores 
begins  similar  to  that  just  described.  In  a  few  days  the 
whole  liquid  is  permeated  by  the  fungus  filaments,  and  on 
the  surface,  new  air-hyphge  appear  and  grow  toward  fructifi- 
cation. Figure  7  shows  the  structure  of  the  sporangium.  The 
external  wall  or  skin  is  covered  with  numerous  small  crystalline 
needles  of  calcium  oxalate.  The  club-like  bunch  shown  in  the 
center  is  the  so-called  columella  (little  column)  ;  it  is  shown 
free  in  Fig.  8  after  the  sporangium  has  been  broken  and 
emptied.  The  columella  is  originally  a  simple  transverse  wall 
which  separates  the  sporangium  from  the  sporangium  stem. 


Fig.  7.  Mucor  Mucedo.    Young  fruit  stem.          Fig.  8.  Old  fruit  stem.     Brefeld. 

If  in  the  study  of  the  air  a  spore  of  Penicillium  glaucum 
had  become  imbedded  we  would  not  observe  as  fine  a  develop- 
ment of  air-hyphae.  Fructification  begins  early  and  a  very 
low  turf  only  is  formed  which  becomes  covered  with  masses  of 
white  spores  turning  later  to  bluish  green.  Under  the  micro- 
scope we  can  see  on  the  ends  of  the  air-hyphae  the  growth  of 
lateral  bunches  or  branches  with  finger-like  spore-supporting 
organs,  so-called  sterigmata.  When  a  spore  is  fully  developed 
a  new  one  is  immediately  formed,  which  remains  loosely  united 
to  the  first.  This  process  repeats  itself  and  by  undisturbed 
growth  gives  rise  to  beautiful  spore  chains  resembling  strings 


122  RESOLUTION    OF    RACEMIC    BODIES 

of  pearls  and  containing  fifty  or  more  members.     See  Figs.  9 


Fig.  9.     Penicillium  glaucum.     Hvphse.  Fig.  10. 

(From  Biefeld.  Hot.    Unters.    liber  Penicillium. 

Schimmelpilze,  i.     Heft,  1872.) 


Piece  of  asexually  fructifying 
urn.    Mvcelia.    From  Brefeld. 


and  10.  Fig.  10  further  shows  that  this  mold,  as  distinguished 
from  Mucor  Mucedo,  contains  transverse  walls  in  the  stem  in 
large  numbers;  in  other  words  the  stems  are  divided. 

In  order  to  take  these  spores  from  the  spore  case  by  the  aid 
of  a  needle  this  is  best  dipped  first  in  the  nutrient  medium  or 
in  sterile  water. *  The  spores  are  dry  and  would  not  cling  to  a 
dry  needle  very  well;  but,  as  distinguished  from  Mucor 
spores,  they  are  not  moistened  immediately  as  the  contents,  and 
apparently  the  membrane  also  contains  fat.  They  distribute 
themselves  uniformly  over  the  droplet  on  the  needle-point  in 
the  form  of  a  thin  dry  layer.  In  consequence  of  these  pecu- 
liarities this  mold  is  spread  very  rapidly  through  the  air  ;  the 
physiologist  attempting  to  produce  pure  cultures  has  much  to 
fear  from  its  ubiquity. 

In  appearance  and  behavior  Aspergillus  glaucus,  Fig.  n, 
stands  close  to  Penicillium  glaucum.  Here,  also,  long  spore 
chains  grow  on  sterigmata,  but  the  latter  are  all  situated  on 
club-like  expansions  of  the  undivided  fruit  stalk.  Several 

1  The  distilled  water  of  the  laboratory  is  not  sterile;  it  often  contains  100,000  or 
more  germs  to  the  cubic  centimeter. 


BY    AID    OF    FUNGI 


123 


Fig.  ii. 


varieties  have  also  branched  sterigmata,— 
the  Sterigmatocysti. 

Frequently  mycelia  develop  on  the  gela- 
tine unaccompanied  by  fructification,  even 
with  Penicillium  and  Aspergillus  varieties. 
As  broken-off  pieces  of  the  filaments  are  ca- 
pable of  growth,  it  is  sufficient  to  pick  up  a 
little  of  the  mycelium  with  a  needle  and  de- 
posit it  in  a  nutrient  medium. 

While  the  common  molds  as  Penicillium 
glaucum,  Aspergillus  glaucus,  and  others, 
may  nearly  always  be  obtained  from  the 
air,  yeasts  are  found  less  often.  As  these 
find  the  most  favorable  conditions  of  growth 
in  nature  on  sweet  fruits,  it  follows  that 
they  are  most  commonly  met  with  in  the 
autumn.  As  compared  with  the  mold  my- 

•    •  «  1         •         .1  Aspergillus  glaucus. 

celia,    they    grow    almost   invisibly    in  the  (Burotiumherberionun) 

,  ,  .    ,,       •       , ,       c  c  Spore-chain,  m  Mvcel. 

nutrient  gelatine,  and  especially  in  the  form  After  Kny,  wan  charts. 
of  small,  white  pinhead-like  colonies.  It 
is  only  occasionally  that  one  finds  colonies  that  are  spread  out 
superficially  ;  these  consist  then  generally  of  aerobiotic  mold 
yeasts.  It  is  very  difficult,  even  by  the  aid  of  the  microscope,  to 
determine  directly  what  form  of  yeast  one  has  found.  In  order 
to  reach  a  certain  comparison  with  forms  already  known,  there 
is  required  usually  a  long  series  of  culture  experiments  which 
may  consume  weeks  or  months.  If  one  desires  to  further  culti- 
vate one  of  the  colonies  found  in  the  gelatine  in  a  new  nutri- 
ent solution,  the  inoculation  must  take  place  with  a  sterilized 
needle.  It  is  sufficient  if  only  a  part  of  a  colony  remains 
clinging  to  the  needle,  as  this  much  will  contain  thousands  of 
cells  capable  of  development. 

That  which  appears  to  us  very  strange  in  the  behavior  of 
the  yeasts  is  the  fact  that  physiologically  very  differently 
acting  forms  exhibit  almost  no  differences  in  the  appearance  of 
their  cells.  After  having  mixed  four  or  five  different  varieties 
in  a  little  drop,  we  are  often  no  longer  able  from  the  micro- 
scopic image  to  pick  out  the  separate  cells.  The  cell  forms, 


124  RESOLUTION    OF    RACEMIC    BODIES 

Figs.  12  to  14,  which  represent  ,S.  ellipsoideus,  may  be  found  in 
a  large  number  of  beer  and  wine  yeasts.  Simple  pictures  or 
drawings  of  the  cells  are  therefore  quite  insufficient  as  a  means 
of  characterizing  a  definite  yeast  variety. 


Fig    12.  Sacchar.  ellibs.    Conidia        Fig.  13.  Sacchar.  ellips.    Developed  spores.  After 
in  which  internal  formation  Brefeld  from  F.  v.  Tavel :  "Morphologic 

of  spores  has  begun.  derPilze."    Jena  1892. 

The  distinction  between  yeast  cells  in  budding  condition 
offers  the  same  difficulties  as  the  distinction  between  mold 
mycelia  in  which  no  special  seed  forms  have  been  developed. 

With  the  yeasts,  besides  by  bud- 
ding, there  is  a  second  method  of 
fructification  ;  viz. ,  through  the  for- 

Fie   14    Sacchar.  ellips.    Sporangia  .  -          ,  f—^.   . 

the  spores  in  which  are  swollen     matlOn  of  endogenous  Spores.       TlllS 

form  of  seed  which  is  shown  in  the 

two  illustrations  never  comes  to  development  in  fermenting 
liquids,  and  then  also  on  account  of  its  morphological  simplicity 
it  affords  few  characteristic  points  of  differentiation  to  settle  the 
question  of  species.  In  germination  the  spore  passes  imme- 
diately to  the  budding  condition  again. 

In  making  use  of  the  yeast  colonies  obtained  in  air  investi- 
gations it  is  necessary  to  recognize  that  while  in  all  probability 
we  have  secured  pure  material,  a  certain  guarantee  for  it  is 
lacking.  This  can  be  secured  only  by  the  method  introduced 
by  Hansen  of  cultivation  from  a  cell.  With  yeasts  this  method 
of  cultivation  may  be  applied  without  difficulty.  But  with 
the  bacteria  it  often  fails  because  of  their  extreme  minuteness. 
However,  the  colonies  grown  in  gelatine,  as  distinguished 
from  the  yeasts,  present  often  characteristic  color  differences, 
so  that  by  the  eye  alone  a  conclusion  may  be  reached  as  to 
different  forms  present  by  the  simple  variations  in  their  gross 
appearance.  A  greater  variety  in  general  is  observed  also  with 
respect  to  shape  and  size  of  the  single  cells.  By  aid  of  the 
methods  of  pure  culture  it  has  been  found,  as  with  the  yeasts 
and  molds,  that  what  were  formerly  regarded  as  simple  forms 


BY    AID    OF    FUNGI  125 

may  be  resolved  into  several  species.  So,  for  example,  the 
Bacterium  tentio  of  the  older  authors  is  no  longer  regarded  as 
a  single  species,  but  the  name  is  used  as  a  collective  descrip- 
tion. The  different  varieties  of  Proteus,  as  P.  vulgaris,  Zenkeri, 
hominis,  exhibit  about  the  same  behavior  that  was  formerly 
given  as  characteristic  of  B.  termo.  For  bacteria  also  the  rule 
is  true  that  it  is  easier  to  obtain  a  pure  culture  than  to  deter- 
mine its  species. 

From  the  remarks  just  made,  it  appears  clear  that  the 
investigations  of  the  older  authors  /» 

on  the  action  of  organisms  on  race-      & 

mic  bodies  must  be  repeated  under  0  rj    /I 

such  conditions  that  only  pure  cul-    || 
tures  and  germ-free  solutions  may 
be  employed,  and  further  that  care 

must  be  taken  to  prevent  the  ingress  1^<^*mJ^5ffii™ 
of  any  infection  during  the  progress       Pringsh  :  jahrb.  27,  i  (1895). 
of  the  experiment. 

To  make  a  nutrient  solution  germ-free  is  not  difficult  ;  it  is 
simply  necessary  to  boil  it  a  long  time  or  frequently  for  short 
intervals,  the  neck  of  the  flask  being  closed  by  a  wad  of 
cotton.  This  last  may  be  dispensed  writh  in  the  so-called 
Pasteur  flask,  the  neck  of  which  is  continued  by  a  long  bent 
tube. 

Formerly,  experiments  on  resolution  or  splitting  were 
usually  carried  out  by  mixing  the  racemic  body,  3  to  5  grams 
to  the  liter,  with  nutrient  salts  ;  e.  g. ,  with  one  gram  of  potas- 
sium phosphate  and  0.2  gram  of  magnesium  phosphate.  In 
working  with  molds,  a  little  phosphoric  or  sulphuric  acid  was 
added  to  prevent  the  rapid  growth  of  bacteria.  A  small 
amount  of  the  special  organism  used  was  sowed  in.  This  must 
then  grow  gradually  and  develop  its  splitting  power.  It 
appears  to  me  to  be  better  to  add  no  nutrient  salts  to  the 
solution  of  the  racemic  body,  but  to  seed  the  organism 
employed  in  larger  amount.  This  should  be  previously  grown 
in  a  specially  good  nutrient  solution.  In  the  case  of  yeasts, 
for  example,  the  cells  could  be  cultivated  in  sterilized  wort  or 
wine-must,  the  fermented  liquid  poured  off,  and  the  residue 
washed  with  sterilized  and  cooled  distilled  water.  To  the 


126  RESOLUTION   OF    RACEMIC    BODIES 

vessel  containing  the  racemic  body,  the  so-purified  yeast 
material  is  then  added.  The  action  is  much  more  rapid,  and 
the  development  of  accidentally  admitted  germs  avoided. 
Molds  may  be  similarly  separated  from  the  nutrient  solution. 
But  the  preparation  of  an  active  bacterial  sediment  offers 
greater  difficulties.  I  employ  for  this  purpose  long  glass 
tubes,  5  or  6  centimeters  wide,  narrowed  at  each  end,  which  are 
completely  filled  with  the  turbid  nutrient  solution  and  placed 
in  a  horizontal  position.  The  sediment  finds  now  a  large 
surface  for  settling  and  collects  here  as  a  relatively  firm  layer 
which  almost  wholly  remains  when  the  liquid  is  poured  away. 
The  sterilization  of  the  tube  is  effected  by  steaming  and  sub- 
sequent addition  of  a  sterilized  cotton  plug.  The  nutrient 
solution  poured  off  from  the  sediment  (accomplished  by 
forcing  air  in  through  the  cotton  filter),  may  be  replaced 
directly  by  the  solution  of  the  racemic  body.  After  sufficiently 
long  action  the  liquid  may  be  drawn  off  and  fresh  added. 
This  arrangement  of  the  experiment  which  would  be  suitable 
also  for  yeasts  and  molds,  as  the  air  necessary  for  the  growth 
of  the  organisms  may  easily  be  forced  in  through  the  cotton 
filter,  permits  continuous  operation  to  a  certain  degree.  With 
the  molds,  the  tube  should  not  be  quite  filled  with  liquid,  but 
an  air  space  should  be  left  in  which  an  active  mold  surface 
may  be  formed.  With  these  conditions  it  is  likely  that  the 
solution  under  experiment  could  be  allowed  to  flow  through 
slowly  and  continuously.  The  action  here  should  be,  for  this 
reason,  a  very  rapid  and  complete  one,  as  organism  and  liquid 
offer  a  large  contact  surface. 

Information  concerning  the  preparation  of  nutrient  solu- 
tions and  nutrient  gelatine,  the  sterilization  of  vessels  and 
liquids,  the  production  of  pure  cultures  and  the  further  culti- 
vation of  the  same  in  larger  apparatus  on  the  technical  scale  may 
be  found  in  the  work  of  Lindner  :  "  Mikroskopische  Betriebs- 
controle  in  den  Gahrungsgewerben  mit  einer  Einfiihrung  in 
die  Hefereincultur,  Infectionslehre,  und  Hefenkunde.  Mit 
vier  Lichtdrucktafeln  und  105  Textabbildungen.  Verlag, 
Paul  Parey,  Berlin."  On  molds  and  their  cultivation  much 
information  will  be  found  in  the  work  of  Wehmer  :  ' '  Beitrage 
zur  Kc-nnlniss  einheimischer  Pilze."  In  Part  I,  the  citric  acid- 


BY    AID    OF    FUNGI  1 27 

producing  molds  are  discussed  and  the  green  molds  thus  far 
described  of  the  genera  Aspergillus  {Eurotium)  Sterigmato- 
cystis,  Penicillium  and  Citromyces  are  compared  in  tabular  form. 
Part  II  treats  specially  of  the  rotting  of  fruit  and  the  varieties 
of  fungi  which  grow  preferably  on  or  in  solutions  of  organic 
acids.  Part  III  (which  has  not  yet  appeared,  1898)  will  con- 
tain a  monograph  of  the  genus  Aspergillus.  Part  I  was  pub- 
lished in  1893  by  Hahn,  Hannover  and  Leipzig,  the  following 
parts  by  Gustav  Fischer,  Jena.  Finally,  attention  must  be 
called  to  the  book  by  Zopf,  "  Die  Pilze,"  Breslau,  1890,  pub- 
lished by  Edward  Trewendt,  as  the  chapter  on  physiology  has 
been  well  worked  out. 

To  chemists  who  wish  to  concern  themselves  with  the  study 
of  racemic  bodies  it  may  be  recommended  to  visit  fermentation 
laboratories  such  as  are  found  in  Berlin,  Munich,  Vienna, 
Copenhagen,  Xew  York,  Chicago,  and  elsewhere.  It  may  be 
possible  to  obtain  from  these  even  large  quantities  of  pure 
cultures  of  yeasts  or  fungi  materials. 


According  to  a  compilation  by  Winther1  the  following  active 
forms  have  been  obtained  by  the  aid  of  fungi: 

/-  Tartaric  acid  by  Pasteur2  from  ammonium  racemate  by 
addition  of  a  spontaneously  fermented  ammonium  tartrate 
solution,  and  then  by  aid  of  Penicillium  glaucum? 

d-  Tartaric  acid  was  obtained  by  Lewkowitsch4  by  the  action 
of  an  unidentified  schizomycete  (vibrio),  occurring  in  impure 
Penicillium  cultures,  on  ammonium  racemate. 

l-Gly eerie  acid  from  the  racemic  ammonium  salt  by  aid  of 
Pen icilliu  m  gla  ucu  m  ( Le wko witsch  ) . 5 

d-Gly eerie  acid  was  obtained  by  Frankland  and  Frew6  from 
r-calcium  glycerate,  to  whose  solution  peptone,  salts  and 
calcium  carbonate  were  added,  by  the  action  of  Bacillus 
ethaceticus.  Left-rotating  calcium  glycerate  is  produced  which 
yields  right-rotating  free  glyceric  acid  by  treatment  with 
oxalic  acid.  After  long  heating  on  the  water-bath,  solutions 

1  Winther:  Ber.  d.  chem.  Ges.,  28,  3022. 
-  Pasteur:  Compt.  rend.,  46,  615  (1858). 

3  Pasteur  :  Ibid.,  51,  298  (1860). 

4  I^ewkowitsch :  Ber.  d.  chem.  Ges.,  16,  1572. 

5  1,6  wko  witsch:  Ibid.,  16,  2720. 

6  Frankland  and  Frew:  J.  Chem.  Soc.,  59,  96. 


128  RESOLUTION    OF    RACEMIC    BODIES 

of  the  acid  yield  a  slightly  soluble  left-rotating    anhydride. 

d- Lactic  acid  was  obtained  by  Lewkowitsch,1  also  by 
Linossier  from  fermentation  ammonium  lactate  by  the  action  of 
Penicillium  glaucum,  P.  Frankland  and  MacGregor3  observed 
the  formation  of  left-rotating  calcium  lactate,  which  furnished 
the  right-rotating  free  acid,  in  the  spontaneous  fermentation 
of  solutions  of  the  racemic  calcium  salt  to  which  calcium  car- 
bonate, peptone,  and  nutritive  salts  had  been  added.  Sarcolactic 
acid  rotates  to  the  left. 

d-Ethoxysuccinic  add  was  obtained  by  Purdie  and  Walker4 
from  the  r-ammonium  salt  by  Penicillium  glaucum.  The  salts 
also  are  right-rotating. 

l-Aspartic  acid. — A  moldy  solution  of  the  r-acid  in  the  air 
becomes  left-rotating  (Engel).5 

l-Glutaminic  acid  split  off  by  Penicillium  glaucum  (Schulze 
and  Bosshard,6  Menozzi  and  Appiani).7 

Active  leucine,  rotating  to  the  right  in  water,  and  to  the  left 
in  hydrochloric  acid  solution,  was  obtained  from  the  racemic 
product  by  Schulze  and  Likiernik8  by  the  aid  of  Penicillium. 
glaucum,  the  racemic  compound  having  been  formed  by  the 
action  of  hydrocyanic  acid  on  isovaleraldehyde  ammonia.  It 
was  obtained  also  from  the  r-compound  produced  from  fer- 
mentation of  caproic  acid  (Schulze).9 

By  the  use  of  beer  yeast  the  following  have  been  obtained 
from  racemic  sugars: 

l-Glucose  (E.  Fischer),10 
l-Mannose  (E.  Fischer),11 
l-Galactose  (E.  Fischer  and  Hertz),12 
I- Fructose  (E.  Fischer).13 

Lewkowitsch  :  Ber.  d.  chem.  Ges.,  16,  2720. 

I.inossier  :  Bull.  Soc.  Chim.,  [3],  6,  10. 

Frankland  and  MacGregor:  J.  Chem.  Soc.,  63,  1028. 

Purdie  and  Walker  :  Ibid.,  63,  229. 

Engel :  Compt.  rend.,  106,  1734. 

Schulze  and  Bosvh.ml     /.tschr.  physiol.  Chem.,  10,  143. 

Menozzi  and  Appiani  :  Chem.  Centrbl.,  1894,  i,  674. 

Schulze  and  I.ikiernik  :  Ber.  d.  chem.  Ges.,  34,  671. 

Schulze:  Ibid...  36,  56  ;  Ztschr.  physiol.  Chem.,  10,  138. 

-cher:  Ber.  d.  chem.  Ges.,  33,  2620. 
»   Fischer:  Ibid.,  33,  382. 
'-'  Fischer  and  Hertz:  Ibid.,  35,  1259. 
18  Fischer:  Ibid.,  33,  389  ;  37,  2031. 


RESOLUTION    BY   AID   OF    FUNGI  I2Q 

l-a-Propyleneglycol  was  formed  in  a  3  per  cent,  aqueous 
solution  of  the  racemic  compound  made  from  glyceric  acid 
after  sowing  an  impure  fungus  culture  from  cheese,  in  wThich 
Bacterium  termo  was  abundantly  present.  The  preparation  must 
be  perfectly  freed  from  empyreumatic  matters.  Propionic  and 
lactic  acids  were  found  as  products  of  the  fermented  part  (  LeBel ) . * 

The  following  active  alcohols  have  been  made  from  dilute 
aqueous  solutions  of  the  synthetic  preparations  and  all  by  aid 
of  Penicillium  g  la  ucum  : 

l-Methylethyl  carbinol    (Combes  and  Le  Bel),2'3 
l-Methyl-N-propyl  carbinol  (Le  Bel),3 
l-Methylbutyl  carbinol  (Combes  and  Le  Bel),2 
d-Ethylpropyl  carbinol  (Combes  and  Le  Bel),2'3 
d-Methyl-N-amyl  carbinol  (Le  Bel).3 

d-Methylethyl  carbincarbinol  was  obtained  through  fungi 
from  a  mixture  of  r-  and  /-amyl  alcohol  with  destruction  of  the 
latter  (Le  Bel).4 

d-Mandelic  add  was  obtained  by  Lewkowitsch5  by  addition 
of  a  few  spores  of  a  pure  Penicillium  culture  to  a  solution  of 
3  grams  of  the  r- ammonium  salt  in  a  liter  of  water  containing 
i. 25  grams  of  nutrient  salts  with  a  little  sulphuric  or  phos- 
phoric acid  and  carefully  sterilized. 

l-Mandelic  acid  was  formed  in  nine  out  of  twelve  experi- 
ments by  application  of  an  impure  Penicillium  culture,  in  which 
,5*.  ellipsoideus  and  an  undetermined  fungus  (vibrio?)  w7ere 
finally  recognized  in  the  liquid  (Lewkowitsch).6  The  acid 
from  amygdalin  is  left-rotating. 

d-Cinnamic  acid  dichloride  has  been  separated  by  aid  of 
Aspergillus  fumigatus  and  also  by  yeast  (Stavenhagen  and 
Finkenbeiner).7 

l-hobutylpropylethylmethyl  ammonium  chloride  was  obtained 
by  Le  Bel8  from  the  synthetic  compound  by  use  of  a  Penicillium 
culture  which  was  not  quite  pure. 

1  Le  Bell:  Bull.  Soc.  Chim.,  [3],  9,  678;  Compt.  rend.,  93,  53?. 

2  Combes  and  Le  Bel  :  Bull.  Soc.  Chim.,  [3],  7,  551. 

3  LeBel:  Ibid.,   [3],  9,676. 

4  LeBel  :  Compt.  rend.,  87,  213. 

r>  Lewkowitsch  :  Ber.  d.  chem.  Ges.,  15,  1505  ;  16,  1569. 
r-  Lewkowitsch  :  Ber.  d.  chem.  Ges.,  16,  1571. 

7  Stavenhagen  and  Finkenbeiner:  Ber.  d.  chem.  Ges.,  27,  456. 

8  Le  Bel:  Compt.  rend.,  112,  725. 

9 


130  FORMATION   OF   ACTIVE   ISOMERS 

E.  Formation  of  Active  Isomers 

35.  i.  From  Inactive  Materials.  Artificial  Preparation  of  Active 
Compounds. — The  phenomenon,  that  active  bodies  as  occurring 
in  nature  were  always  found  to  be  inactive  when  prepared  syn- 
thetically, led  formerly  to  the  opinion  that  substances  endowed 
with  the  power  of  optical  rotation  could  be  produced  only 
within  the  animal  or  vegetable  cell.  This  view  which  was 
maintained  particularly  by  Pasteur1  had  to  be  abandoned  when 
in  1873  Jungfleisch"  succeeded  in  producing  tartaric  acid  com- 
pletely by  synthesis,  starting  with  ethylene  which  was  con- 
verted into  the  dibromide,  ethylene  cyanide,  succinic  acid, 
dibromsuccinic  acid  and  finally  racemic  acid,  \vhich  wras  split 
up  into  active  components.  Since  it  has  been  recognized  that 
the  inactivity  of  asymmetric  synthetic  compounds  depends  on 
their  racemic  structure,  many  of  them  have  been  produced  in 
active  forms.  Among  such  which  are  found  in  nature,  conine 
may  be  especially  referred  to,  the  complete  synthesis  of  which 
was  accomplished  by  Ladenburg  in  the  following  manner:8 
Starting  with  acetic  acid  this  is  converted  into  acetone,  isopro- 
pyl  alcohol,  glycerol,  allyl  bromide,  trimethylene  bromide,  tri- 
methylene  cyanide,  pentamethylene  diamine,  piperidine,  pyri- 
dine,  o'-picoline,  or-ally!  pyridine  and  finally  into  a-propyl 
piperidine  =  r  conine,  from  which  by  splitting  with  tartaric 
acid  the  af-form,  identical  with  the  natural  conine,  is  secured. 

A  special  method  for  the  synthesis  of  active  compounds, 
has  recently  been  tried  by  Boyd4  as  he  attempted  to  determine 
whether,  when  asymmetric  bodies  were  formed  in  a  magnetic 
field,  one  of  the  antipodes  wrould  not  be  predominant,  leaving 
the  product  endowed  with  rotating  power  and  not  racemic. 
Benzoyl  formic  acid  was  converted  into  mandelic  acid  by 
treatment  with  sodium  amalgam  in  vessels  kept  in  a  magnetic 
field  of  7,000  to  8,000  C.  G.  S.  units,  but  it  was  found  that 
the  product  was  quite  inactive,  and  also  when  the  reaction 
was  carried  out  in  presence  of  active  substances,  such  as 
df-tartaric  acid  or  /-mandelic  acid.  Likewise,  in  the  bromi- 
nation  of  stilbene,  racemic  stilbene  bromide  was  formed.  The 

1  Pasteur:  Compt.  rend.,  81,  128. 

*  Jungfleisch:  Bull.  Soc.  Chim.  [2],  19,  194;  Compt.  rend.,  76,  286. 

»  Ladenburg:  Ber.  d.  chem.  Ges.,  32,  1403;  Ann.  Chem.  (Uebig),  347,  80. 

«  Boyd :  Inaug.  Dissertation,  Heidelberg,  1896. 


FROM    INACTIVE   MATERIALS  131 

magnetic  rotation  to  which  the  molecules  are  subjected  during 
formation,  leaves  no  permanent  result. 

Relative  to  the  synthesis  of  active  substances,  these  con- 
ditions follow  from  the  doctrine  of  asymmetric  carbon  atoms 
as  first  pointed  out  by  van't  Hoff  (Chimie  dans  1'espace, 
1875,  p.  20-28)  : 

a.  If  a  compound  formed  from  ;a  symmetric  substance  has 
but  one  asymmetric  carbon  atom,  then  a  single  racemic  body 
always  results.     The    same    is    true  when  the  molecule  of  a 
resulting  active  compound    contains  two  asymmetric  carbon 
atoms,  but  consists  of  two  similar  halves.     For  example,  from 
succinic   acid  only  one  racemic  dibromsuccinic  acid  may  be 
made. 

b.  If  a  molecule  containing  two  asymmetric  carbon  atoms, 
but  not  consisting  of  two  similar  halves,  is  derived  from  an 
inactive  substance,   the  production    of    two  racemic   pairs  is 
possible,    the   splitting   of   which    must    lead    to  four  active 
isomers.     It  is  not  necessary    that    the    two  racemic   bodies 
should  be  formed  in  equal  amounts,  but,  because  of  different 
degrees  of  stability,  the  formation  of  one  may  be  favored,  and 
that  of  the  other  entirely  suppressed. 

For  example,  cinnamic  acid,  C6H5CH  =  CH.CO.2H,  may 
yield  the  following  cinnamic  acid  dibromides  : 


«5  65  65  65 

II  II 

H—  C—  Br          Br—  C—  H  H—  C—  Br         Br—  C—  H 

H—  C—  Br          Br—  C—  H  Br--C—  H  H—  C—  Br 

II  I  I 

CO2H  CO2H  CO2H  CO,H 

First  racemic  body.  Second  racemic  body. 

According  to  Liebermann  and  Hartmann,1  the  inactive 
bromination  product  of  cinnamic  acid  does  not  probably  con- 
tain the  two  racemic  pairs,  but  only  one,  the  splitting  of  which 
up  to  the  present  time  has  led  to  antipodes  with  rotations, 
\_oi\D  =-.  :  -j-  55°  and  —  41°.  The  other  racemic  compound  has 
been  obtained  by  Liebermann2  by  bromination  of  the  labile 
allocinnamic  acid,  and  decomposed  approximately  into  com- 
ponents with  \_a\  -  --  -f  64°  and  —  71°. 

1  Liebermann  and  Hartmann  :  Ber.  d.  chem.  Ges.,  26,  1664. 
a  Liebermann  :  Ibid.,  27,  2037. 


132  FORMATION   OF   ACTIVE   ISOMERS 

36. — 2.  From  Active  Materials. — The  following  cases  may 
appear  : 

a.  A  body  with  one  asymmetric  carbon  atom  may  be  converted 
into  a  compound  with  two  such  atoms.  According  to  the  van 't 
Hoff-Le  Bel  theory,  an  active  molecule,  CR1R2R3R4,  whose 
right-rotating  configuration  is  shown  by  I  below,  must  furnish 
two  isomeric  products,  la  and  Id,  which  are  not  corresponding 

i 

antipodes,    by   the   introduction    of   the    group,    R5 — C — R6. 

They  possess,  therefore,  different  properties,  and  may  be  pro- 
duced in  unequal  amounts.  Likewise  from  the  left-rotating 
configuration,  II,  the  not-antipode  isomers,  Ila  and  lid  are 
formed  : 

Id. 

J 

R4-C-R2 
R6-C-R5 

R3 
II.  Ila.  lid. 

I1  I'  I' 

R2— C— R4          R2— C— R4         R,— C— R4 

RS  RS — C — R6         R6 — C  — RS 

R3  RS 

In  this  case  the  original  right-  or  left-rotating  substance 
does  not  yield  a  racemic  body  by  the  chemical  change,  but  a 
mixture  of  two  active  isomers  which  must  possess  unequal 
rotating  powers.  The  relations  are  therefore  different  from 
what  they  are  in  the  syntheses  from  inactive  bodies. 

Among  the  above  four  isomers,  each  two  form  true  antipodes  ; 
viz.,  la  with  11^,  and  Id  with  Ila,  which  may  be  combined 
to  form  two  racemic  compounds.  A  mixture  of  these  two 
last  must  result  when  the  racemic  form,  I  -f-  II,  of  the  original 
substance  is  subjected  to  the  chemical  reaction,  the  final 
product  being  then  inactive. 

As  a  matter  of  course,  the  case  remains  the  same  if  the  new 
asymmetric  carbon  atom  is  produced,  not  through  addition , 


I. 

la. 

RI 

RI 

R4-C-R2 

R4-C-R2 

R3 

R5-C-R6 

1 

R3 

FROM    ACTIVE    MATERIALS  133 

but  from  one  of  the  symmetric  carbon  atoms  already  present 
in  the  molecule. 

The  above  relations  pointed  out  by  van't  Hoff,  may  be 
expressed  in  the  following  manner  if  the  two  asymmetric 
groups  in  the  four  isomers  be  represented  by  ±  A  and  ±  B  : 

f     i_      A     I       n 

The  original  -f  compound  furnishes  the  bodies:          _  ^_  g 
-compound  " 

and  the  two  pairs  of  antipodes  are : 

+  A  +  B\  ,     +  A  — 

-A-B]    and    -A  + 

If  the  specific  rotations  of  the  four  isomers  are  known,  the 
rotating  powers  of  the  groups  A  and  B  may  be  calculated. 
•  These  theoretical  predictions  have  been  frequently  confirmed 
by  experiment.  If,  for  example,  limonene  be  converted  into 
the  nitrosochloride  compound,  C10H16.NOC1,  by  treatment 
with  amyl  nitrite  and  hydrochloric  acid  with  addition  of  acetic 
acid,  which,  with  great  probability,  gives, 


CH3        CH2 

CH3  CH2 

Y 

Y 

*CH 

*CH 

/\ 

/\ 

H2C        CH2 

H2C        CH2 

I          | 

1          1 

H2C        CH 

H2C         CH.NO 

Y 

*CC1 

1 

1 

CH3 

CH3 

Limonene. 

Lirnonenenitrosochloride. 

there  are  always  formed  from  the  latter  substance,  according  to 
Wallach,1  two  isomers  (a  and  fi}  which  may  be  easily  sepa- 
rated by  their  different  solubilities  in  ether.  There  results 
from 

+  Limonene  {-nitrosochloride  [a]f=  +  3,3.4° 

fa-  "  "  —  —  V4.8 

-  Limonene  |  ^  „  «  =  _  242.2 

The  two  « -compounds  on  the  one  hand,  and  the  two  /?-com- 
pounds  on  the  other,  represent  optical  antipodes. 

1  Wallach:  Ann.  Chem.  (Liebig),  252,  108 ;  270,  171. 


134  FORMATION   OF   ACTIVE    ISOMERS 

In  the  reaction  the  a-nitrosochlorides  are  formed  in  larger 
amounts  than  the  ^-products;  the  first  crystallize  in  well- 
formed  monosymmetric  prisms  which  dissolve  easily  in  ether, 
but  decompose  quickly  on  keeping;  the  latter  are  finely  crys- 
talline, difficultly  soluble  in  ether,  and  much  more  stable. 
Chemically  the  a-  and  y#-isomers  behave  in  a  similar  manner; 
the  latter,  however,  in  benzene  solution  show  a  double  molec- 
ular weight  (Wallach).1 

Dipentene  (^-/-limonene)  is  an  inactive  product  which  is  a 
mixture  of  two  racemic  bodies  (Wallach).2 

Of  the  two  asymmetric  carbon  atoms  in  the  limonene  nitroso- 
chlorides,  one  may  be  easily  destroyed.     This  happens  when 
each  compound  is  treated  with  alcoholic  potash  solution   by 
which,  with  loss  of  H  -f-  Cl,  they  become    transformed   into, 
carvoximes,  Cj0Hl4.NOH  : 


CH3  CH2 

CH3  CH2 

Y 

C 

1 

1 

*CH 

*C 

/\ 

/\ 

H2C        CH2 

H2C         CH2 

1          1     ' 

1          1 

H2C         CH.NO 

HC         C=NOH 

*CC1 

Y 

1 

| 

CH3 

CH3 

Limonenenitrosochloride. 

Carvoxime. 

The  carvoxime  appears  only  in  twro  forms  (d  and  /),  and 
therefore,  from  the  a-  and  yS-nitrosochloride  of  the  same  kind, 
the  same  product  must  result.  This  was  found  by  Wallach5 
to  be  the  case,  a  change  in  the  direction  of  rotation  following: 

From  +    j«-_nitrosochloride  j   ^^  _  carvoxime  [a]z)  =  _  39  ^ 

{£  «<  "      -h  carvoxime      "  ==  +  39.7. 

b.  If  in  a  body  which  contains  several  asymmetric  carbon  atoms ; 
the  number  of  the  latter  be  increased  by  one,  the  same  conditions 
which  have  just  been  discussed  must  obtain,  —the  new  substance 

1  Wallach:  Ber.  d.  chem.  Ges.,  28,  1308. 

2  Wallach  :  Ann.  Chem.  (Liebig),  270,  175. 
»  Wallach  :  Ibid.,  346,  227. 


FROM    ACTIVE    MATERIALS  135 

must  exist  in  two  isomeric  forms.  E.  Fischer1  has  furnished 
the  experimental  proof  of  this  as  he  found  that  from 
<*-glucoheptose,  C7HUO7,  ([«]/>  =  -  19.7°,  c=  10,  water) 
two  different  glucooctonic  acids,  CfeH16O9,  may  be  obtained  by 
the  cyanide  reaction,  of  which  the  one,  as  lactone,  has  the 
rotation,  [**]/>  =-  -f  45-9°,  and  the  other  -j-  23.6°  (in  water, 
r—  10).  In  these  cases,  it  has  been  well  established  that  the 
configuration  formulas  are  : 

COOH        COOH 

CHO  H— C— OH     HO— C— H 

H— C— OH  H— C— OH      H— C— OH 

I  I  I 

H— C— OH  H— C— OH      H— C— OH 

I  I  I 

HO— C— H  HO— C— H      HO— C— H 

I  I  I 

H— C— OH  H— C— OH      H— C— OH 

H— C— OH  H— C— OH      H— C— OH 

I  I  I 

CH2OH  CH.OH         CH2OH 

a-Glucoheptose.  Glucooctonic  acid. 

In  the  same  way  two  isomeric  rhamnohexonic  acids, 
C7HUO:,  whose  lactones  have  the  rotations  [d]D  =-.  -f  83.8° 
and  +43.3°,  are  formed  from  rhamnose,  C6H12O5  (Fischer  and 
Piloty).2  On  the  contrary  from  mannose,  C6H12O6,  by  aid  of 
the  cyanide  reaction,  only  one  of  the  mannoheptonic  acids, 
CTH14O6,  could  be  obtained ;  ^-mannose  furnished  a  left- 
rotating  acid  lactone  ([0?]^  =  -  74.2°)  ;  /-mannose  a  right- 
rotating  ([of\D=  -\-  75. 2°).  The  two  corresponding  antipodes 
were  therefore  formed  which  united  to  produce  a  crystalline 
compound.  This  case  shows  that  the  formation  of  one  of  the 
two  possible  isomers  may  be  particularly  favored  ( Fischer,8 
Smith,4  Hartmann).5 

c.  Increase  of  the  number  of  asymmetric  carbon  atoms  takes  place 
also  by  the  combination  of  active  bases  with  active  acids,  in  which 
case  two  pairs  of  antipodes  with  different  properties  must 

1  Fischer  :  Ann.  Chem.  (lyiebig),  270,  64. 

'-  Fischer  and  Piloty  :  Ber.  d.  chem.  Ges.,  23,  3104. 

3  Fischer  and   Hirschberger :  Ibid.,  22,   370;   Fischer    and  Passmore  :    Ibid. ,23, 
2226. 

4  Smith  :  Ann.  Chem.  (Liebig),  272,  182. 

5  Hartmann  :  Ibid.,  272,  190. 


136  FORMATION   OF   ACTIVE    BODIES 

result.  Of  salts  of  this  kind,  the  following  have  been  made  : 
Marckwald1  has  combined  d-  and  /-or-pipecoline  with  d-  and 
/-tartaric  acid,  forming  acid  tartrates,  the  water  of  crystalli- 
zation, melting-points,  and  crystalline  forms  of  which  he 
determined.  He  did  the  same  with  the  salts  from  racemic 
acids  and  bases.  The  results  were  : 

Melting-point. 


-f-  Tartaric  acid  -f  pipecoline 


The  acid  tartrates  of  d-  and  l-limonene-a-nitrolbenzylamine, 
C10H16.NO.NH.CH2C6H5,  were  examined  by  Wallach  and 
Conrady2  with  respect  to  their  rotation.  The  solutions  in 
aqueous  alcohol  contained  0.97  to  1.38  per  cent  of  salt  : 


Water  of 

Anhy- 

crystalli-                                              Hydrated  drous 
zation.          Crystalline  form.            salt.         salt. 

•• 

{monoclinic        } 
hemimorphous     >• 
enantiomorphous  j 

65- 
66° 

III- 
II2C 

"                       ? 

45- 

126° 

"  I 

46° 

— 

I 

"                monociinic 

85° 

— 

-f  tartaric  acid  -f-  base,  [a]D=  —  49.9 


(± 
{± 


"  =  +  69-6° 
"  =    -  69.9° 


From  this  the  rotations  follow  : 


-f-  base  =  —  60°  -|-  acid  =  +  10° 

"       =   =   +  60  "  -   10° 

In  the  two  bases  a  change  of  rotation  follows  on  combination 
with  tartaric  acid. 

The  following  observations  have  been  made  by  Fileti3  on 
salts  of  d-  and  /-isopropylphenylglycolic  acid  (  \oi\  D  =  zb 
135°)  with  quinine  and  cinchonine  : 

Melting-point-          [<*]z> 

-f  Isopropylphenylglycolic   acid  —  quinine,      192-193°  79-4° 

204-205  -  118.4 

-f-  "         "  "      -f  cinchonine     201  -f-  136.8 

167  +    83.4 

From  this  the  differences  in  the  two  not-antipodic  isomers  are 
apparent. 

1  Marckwald  :  Ber.  d.  chem.  Ges.,  39,  43. 

2  Wallach  and  Conrady  :  Ann.  Chem.  (Uebig),  353,  148. 

*  Fileti  :  Gazz.  chim.  ital.,  aa,  II,  395  ;  Ber.  d.  chem.  Ges.,  a6,  IV,  89. 


IN   THE   ANIMAL   OR   VEGETABLE    CELL  137 

37. — 3.  Formation  of  Active  Bodies  in  the  Animal  or  Vegetable  Cell. 
— In  the  production  of  asymmetric  bodies  in  the  vegetable 
cell  from  inactive  materials,  it  might  be  expected,  as  in 
artificial  syntheses,  that  the  two  antipodes  would  be  formed 
and  racemic  bodies  result.  Secondly,  it  might  be  possible  that 
of  the  different  configurations  of  a  molecule,  several,  or  indeed 
all  might  be  formed  at  the  same  time.  As  far  as  experience 
has  shown,  up  to  the  present  time,  however,  of  such  possible 
plant  isomers,  only  one  is  produced,  and  this  generally  one  of 
the  active  forms.  Of  the  hexoses  only  the  right-rotating 
^- glucose,  of  the  ketoses,  only  the  left-rotating  ^-fructose 
appears  (E.  Fischer),1  of  the  four  tartaric  acids,  only  the 
active  right-rotating  form.  The  same  thing  is  seen  in  whole 
groups  of  vegetable  substances,  such  as  the  bitter  principles 
and  alkaloids,  which  have  all  been  found  in  one  of  the  two 
active  forms  only.  In  the  turpentine  oils  from  the  different 
species  of  pine,  as  well  as  in  other  ethereal  oils  there  is  found 
either  ^-pinene  and  aMimonene,  or,  on  the  other  hand,  /-pinene 
and  /-limonene  ;  but  at  the  same  time  dipentene  may  also  be 
contained  in  them,  and  we  have  here  a  case  of  the  formation 
of  a  racemic  body  in  the  plant. 

A  suggestion  of  the  manner  in  which  new  active  bodies  may 
be  made  from  others  already  present  in  the  plant-cell  has  been 
given  by  E.  Fischer.2  This  is  based  on  the  fact  that  in  the 
artificial  building  up  of  sugars  from  others  of  a  smaller 
number  of  carbon  atoms  by  aid  of  the  cyanhydrin  reaction,  the 
once  existing  asymmetry  of  the  molecule  is  further  continued. 
Imagine,  for  example,  the  conversion  of  mannose  by  the 
addition  of  cyanhydric  acid  three  times  into  mannononose,  and 
this  then  so  split  up  that  the  original  hexose  would  be 
reproduced,  then  the  second  compound  writh  three  carbon 
atoms  would  be  also  an  active  system  ;  the  first  active  molecule 
has  produced  a  second  one.  In  the  same  manner  from  the 
active  substances  in  the  chlorophyl  grains,  which  are  held  by 
vegetable  physiologists  to  be  the  seat  of  the  formation  of 
sugar,  this  latter  body  could  be  formed  by  the  taking  up  of 
carbonic  acid  or  formaldehyde,  condensation,  and  final  splitting 

1  E.  Fischer:  Ber.  d.  chem.  Ges.,  27,  3230. 

2  E.  Fischer  :  Ibid.,  27,  3231. 


138  TRANSFORMATION  OF  THE  ACTIVE  ISOMERS 

off.  As  sugar,  in  turn,  is  used  by  the  plant  in  the  formation 
of  other  organic  substances,  these  furnish  the  material  for  the 
production  of  new  chlorophyl  grains  which  again  build  up 
sugar,  and  thus,  a  direct  and  continuous  creation  of  asym- 
metric molecules  takes  place.  Similar  views  have  been 
expressed  by  Stohmann.1 

In  what  manner  the  first  active  substance  is  formed  in  the 
plant-cell  can  not,  of  course,  be  explained,  nor  also,  the  reason 
why  in  one  body  the  formation  of  a  right-rotating  and  in 
another,  of  a  left-rotating  modification  is  preferred.  The 
assumption  that  both  forms  are  simultaneously  produced  and 
one  immediately  destroyed,  that  is,  used  to  build  up  other 
substances,  appears  untenable,  as  the  last  process  could  not 
take  place  momentarily,  and  racemic  bodies  should  then  be 
found  in  part  in  plants,  which,  as  remarked  above,  is  very 
seldom  the  case. 

In  the  animal  organism  which  is  formed  mainly  of  asym- 
metric substances,  and  receives  such  as  food,  the  production  of 
new  active  compounds  by  addition  and  decomposition  can 
follow.  With  this,  there  is  the  possibility  that  inactive 
bodies  present  may  take  part  in  the  changes,  and  so  be  con- 
verted into  active  substances.  This  is  shown,  for  example,  by 
the  observation  that  brombenzene  taken  into  the  organism  ap- 
pears in  the  urine  as  active  bromphenylmercapturic  acid.2 

It  is  remarkable  that  the  proteid  bodies  of  the  animal 
kingdom,  and  also  of  the  vegetable,  show,  without  exception, 
left  rotation.  On  the  other  hand,  the  bile  acids  nearly  all  ro- 
tate to  the  right. 

F.  Transformation  of  the  Active  Isomers 

38.  Reciprocal  Transformation  of  the  Antipodes.  —  A  general 
method  by  which  active  bodies  may  be  half  converted  into 
oppositely  rotating  antipodes  consists  in  converting  them  into 
racemic  forms  and  splitting  these.  In  this  way  Lewkowitsch3 
obtained  from  /-mandelic  acid  the  ^-acid.  Piutti4  by  treating 

1  Stohmann  :  Ztschr.  f.  Biologic,  Jahrg.,  1894. 

2  Jaff6  :  Her.  d.  chem.  Ges.,    ia,   1092  :    Baumann  and   Preusse  :    Ztschr.  physiol. 
Chem.,  5,  309;  Baumann  :  Ber.  d.  chem.  Ges.,  15,  1731. 

3  Lewkowitsch:  Ber.  d.  chem.  Ges.,  16,  2722. 

«  I'iutti:  Gaz.  chim.  Hal.,  17,  126;  Jahresbericht,  (1887),  1664. 


TRANSFORMATION  OF  THE  ACTIVE  ISOMERS  139 

</-asparagine  with  alcohol  and  hydrochloric  acid  obtained  the 
racemic  monoethyl  ester  of  aspartic  acid,  from  which  by  treat- 
ment with  ammonia  he  obtained  asparagine  again  in  the 
racemic  form,  and  this  was  finally  split  by  crystallization. 
This  method,  however,  has  but  a  limited  application  because 
with  a  large  number  of  substances  racemization  can  be  brought 
about  with  difficulty  or  not  at  all. 

A  quite  distinct  process  for  the  transformation  of  the  anti- 
podes was  applied  by  Walden1  in  the  case  of  malic  acid.  By 
treating  the  common  /-acid  ([«]/>  =  -  5°  to  5.3°  in  acetone, 
c  =  13  to  16)  with  phosphorus  pentachloride  with  addition  of 
chloroform,  thus  avoiding  high  temperature,  active  mono- 
chlorsuccinic  acid  results  and  in  the  right-rotating  form.  By 
now  replacing  the  chlorine  in  this  by  hydroxyl  (by  boiling  the 
aqueous  solution,  neutralized  with  potassium  carbonate,  with 
silver  nitrate)  malic  acid  results,  and  this  rotates  just  as  much 
to  the  right  as  the  original  acid  did  to  the  left.  On  the  other 
hand,  the  */-acid  so  obtained  yields  /-monochlorsuccinic  acid  on 
treatment  with  phosphorus  pentachloride  and  from  this  /-malic 
acid  may  be  reproduced.  We  have  thus  a  perfect  cycle  of 
changes.  The  conversion  of  either  of  the  two  malic  acids 
into  the  other  ma}r  be  brought  about  by  converting  the  corre- 
sponding dimethyl  ester,  wThich  has  the  same  rotation  into  the 
dimethyl  chlorsuccinic  ester  by  aid  of  phosphorus  pentachloride, 
and  in  this  conversion  the  direction  of  rotation  changes. 

An  explanation  of  the  peculiar  change  in  rotation  and  mol- 
ecular configuration  which  follows  in  the  substitution  of  hy- 
droxyl by  chlorine  under  the  action  of  PC15  has  been  attempted 
by  Armstrong.2 

Of  a  different  kind  are  a  number  of  observed  changes  of 
active  bodies  into  oppositely  rotating  isomers,  inasmuch  as  the 
latter  are  not  the  true  antipodes  of  the  original  substances, 
which  follows  from  the  fact  that  racemic  compounds  do  not 
result  as  end  products.  The  inversion  of  /-menthone  into 
d'-menthone,  or  the  reverse,  which  follows  by  the  action  of 
weak  or  strong  sulphuric  acid,  hydrochloric  acid  or  alcoholic 

1  Walden:  Ber.  d.  chem.  Ges.,  29,  153. 

2  Armstrong:  Proceedings  Chem.  Soc.,  (1896),  page  45.     On  the  change  of  d-lactic 
acid  into /-lactic  acid,  see  Purdie  and  Williamson  :  J.  Chem.  Soc.,  69,  837. 


140 


MODIFICATIONS  OF   INACTIVE  CONFIGURATION 


potash,  and  which  was  discovered  by  Beckmann1  is  a  case  in 
point.  In  the  same  way  /-ecgonine  and  /-cocaine  may  be  con- 
verted by  heating  into  right-rotating  isomers  (Einhorn  and 
Marquardt).2 

See  further  the  chapter  on  the  direction  of  rotation  of  the 
derivatives  of  active  bodies. 

39.  Reciprocal  Transformation  of  Active  Isomers  of  Different 
Configurations.  —  Such  changes  were  discovered,  as  is  known,  by 
E.  Fischer,3  and  especially  in  the  acids  of  the  sugar  group.  They 
occur  when  these  acids  are  heated  with  quinoline  or  pyridine  to 
I3o°-i50°,  in  which  the  addition  of  the  bases  is  employed 
mainly  to  prevent  the  production  of  lactones  which  interfere 
with  the  reaction.  According  to  experience  up  to  the  present, 
a  change  of  position  of  the  H  and  OH  on  the  asymmetric 
carbon  attached  to  thecarboxyl  group  follows,  and  this  reaction 
appears  to  be  always  reversible,  so  that  the  product  is  a  mix- 
ture of  the  original  acid  with  the  one  newly  formed.  Thus, 
the  following  stereoisomeric  acids  have  been  reciprocally  con- 
verted, the  one  into  the  other.4 


C5H1006 


/-Arabonic  acid 

*1  9  v>        ^TL 

d-Gluconic  acid 

A     •   •  X  •     x 

1     X  X  •  X    " 

/-Gluconic  acid 

X 
df-Galactonic  acid 


X  X  •  X 

.  .  x  • 


x  •   •  X 


/-Ribonic  acid 
A   xxx    X 

d-Mannonic  acid 

A     • • XX     v 
^    XX  •    •     A 

/-Mannonic  acid 

A    X  X  •   •      x 
••XX' 

^/-Talonic  acid 
A    ^xxx    A- 


/-Gulonic  acid  |^      /-Idonic  acid 


A     *  x  *   ' 
**     X  •  X  X 


•  X  •  X 
X  •  X  • 


Besides  these  cases  others  are  known. 
G.  Inseparable  Modifications  of  Inactive  Configuration 

40.    As  already  explained  in  the  chapter  on  the  number  of 
isomers  possible  in  bodies  with  asymmetric  carbon  atoms  (§  16) 

1  Beckmann:  Ann.  Chem.  (Liebig),  250,  342;  289,  362. 

2  Einhorn  and  Marquardt:  Ber.  d.  chem.  Ges  ,  23,  468,  979. 
8  E.  Fischer  :  Ibid.,  23,  799  ;  24,  2137,  3622  ;  27,  3193. 

*  In  the  formulas  A  =  CH2OH,  X  =  CO2H,  •  =  H,  X  =  OH. 


MODIFICATIONS  OF  INACTIVE  CONFIGURATION  14! 

this  type  may  appear  in  such  molecules  whose  formulas  may 
be  divided  into  two  equal  halves.  The  inactivity  may  be 
explained  by  the  equally  strong  but  oppositely  directed  rotating 
power  of  the  two  halves  which  compensate  each  other. 

The  correctness  of  this  view  follows  from  the  fact  that  when 
the  symmetry  of  such  a  molecule  is  destroyed,  an  active  pro- 
duct results.  This  was  shown  first  by  E.  Fischer.1  As  he 
found,  the  inactive  mucic  acid,  CO2H— (CHOH)4— CO2H, 
yields  by  reduction  racemic  galactonic  acid,  CHO— 
(CHOH)4 — CO2H,  which  may  be  split  into  active  components, 
and  conversely  these,  as  well  as  the  galactoses,  may  be  con- 
verted by  oxidation  into  inactive  non-separable  mucic  acids. 

Inactive  isomers  of  this  kind  are  found  in  the  following 
classes  of  symmetric  bodies  : 

i.  In  chain  structure  compounds  with  an  even  number  of  car- 
bon atoms. — In  this  case,  according  to  §  16,  the  number,  i,  of 

n 

inactive  modifications  is  given  by  the  formula,  i  =  2 2  ,  where 
n  is  the  whole  number  of  asymmetric  carbon  atoms.  The 
bodies  of  this  group  which  are  known  are  mainly  these  : 

Among  those  with  n  =  2,  where  i=i,  there  is,  first  of  all, 
the  meso-  or  antitartaric  acid  discovered  by  Pasteur2  in  1853, 
in  which  the  impossibility  of  resolution  and  consequent  dif- 
ference from  racemic  acid  (paratartaricacid)  was  shown.  The 
configuration  of  this,  as  also  that  of  erythritol,  whose 
inactivity  has  also  been  «hown,  must  be  given,  according  to 
§16,  by 

COOH  CH2OH 

I  I 

H— C— OH  H— C— OH 

I  I 

H— C— OH  H— C— OH 

COOH  CH2OH 

Mesotartaric  acid.  Erythritol. 

A  further  number  of  such  symmetric  bodies  as  the  di-  and 
tetrasubstituted  succinic  acids,  also  erythritol  derivatives, 
hydrobenzoin,  etc. ,  are  undoubtedly  likewise  inactive. 

Among  compounds  with  n  =4,  and  consequently  i  =  2  we 
have  : 

1  E.  Fischer:  Ber.  d.  chem.  Ges..  25,  1247,  1260. 

2  Pasteur  :  Compt.  rend.,  37,  162.    See  Pryzbytek  :  Ber.  d.  chem.  Ges.,  17,  1415. 


142  MODIFICATIONS   OF  INACTIVE   CONFIGURATION 


CH2OH 

COOH 

COOH 

I 

I 

I 

H—  C—  OH 

H—  C—  OH 

H—  C—  OH 

I 

1 

1 

HO—  C—  H 

HO—  C—  H 

H—  C—  OH 

I 

1 

1 

HO—  C—  H 

HO—  C—  H 

H—  C—  OH 

| 

| 

1 

H—  C—  OH 

H—  C—  OH 

H—  C—  OH 

1 

1 

1 

CH2OH 

COOH 

COOH 

Dulcitol. 

Mucic  acid. 

Allomucic  acid. 

With  the  octitols  and  their  corresponding  acids,  four  isomers 
with  inactive  configuration  are  possible,  but  we  are  not  yet 
acquainted  with  them. 

Naturally  no  change  follows  in  the  above  relations,  if  an 
even  number  of  carbon  atoms  with  two  similar  radicals 
attached  (CHa  groups)  are  introduced  into  the  middle  of  the 
molecule,  as  is  the  case  with  : 

Dimethyladipic  acids, 

( CO2H— *CH.  CH3 )— CH2— CH2— ( *CH.  CH,— CO2H ) . 
Diallyl  bromides,  (CH2Br— *CHBr)—  CH2— CH2— (*CHBr— CH.2Br). 

and  others. 

2 .  In  chain-structure  compounds  with  an  uneven  number  of 
carbon  atoms. — Here  the  number  of  possible  isomers  is 
dependent  on  the  form  of  combination  of  the  radicals  with  the 
middle  carbon  atom. 

a.  If  the  middle  carbon  atom  besides  being  united  with  the 
two  symmetric  groups  is  joined  to  two  other  radicals,  similar 
to  each  other,  as  in  the  tf-dimethylglutaric  acids, 

(CO,H—  *CH.CH3)— CH2— (*CH.CH3-C02H), 
then  the  number  of  inactive  isomers  may  be  calculated  by  the 
formula  used  for  the  bodies  of  the  last  group. 

b.  If,  on  the  other  hand,  the  middle  carbon  atom,  besides 
being  attached  to  the  symmetric  groups,  is  joined  to  two  other 
dissimilar  radicals,  then  the  number  of  inactive  isomers  may  be 


found  by  the  formula,  i  =  2  ,  where  n  is  the  number  of 
asymmetric  carbon  atoms,  the  middle  carbon  atom  being  included 
as  one.  In  reality,  •  however,  this  atom  should  not  be  con- 
sidered as  asymmetric,  because,  as  a  glance  at  the  following 
configuration  formulas  will  show,  a  plane  of  symmetry  may  be 


MODIFICATIONS  OF  INACTIVE    CONFIGURATION  143 

passed  through  the  same,  and  the  dissimilar  radicals  joined  to 
it.     If  this  middle  carbon  atom  is  excluded,   the  number  of 

n 

inactive  isomers  is  given  by  the  formula,  t  =  2  2 
The  following  are  bodies  of  this  class  : 


CH,OH 

CH2OH 

C02H 

C02H 

1 

1 

i 

H—  C—  OH 

H—  C—  OH 

H—  C—  CH, 

H—  C—  CH3 

H—  C—  OH 

HO—  C 

:—  H 

H—  C—  CH3 

H3C-C—  H 

H—  C—  OH 

H—  C—  OH 

H—  C—  CH3 

H—  C—  CH3 

CH2OH 

C 

:H,OH 

C02H 

CO2H 

Adonitol  (ribitol"). 

Xvlitol. 

, 

Ribotrioxylglutaric     Xylotrioxyglutaric      Trimethylglutaric  acids, 
acid.  acid'. 

Bodies  which  contain   five,  or  according  to  the  above  con- 
siderations four,  asymmetric  carbon  atoms,  furnish  four  inac- 
tive isomers   of  which  at  present    tf-glucoheptonpentoldiacid, 
OH     OH     H       OH     OH 

I          I          I          I          I 
C0.2H C C C C C C02H 

I          I          I          I          I 
H        H        OH     H        H 

and  ar-glucoheptitol  are  known. 

3.  In  cis-form  cyclic  compounds.  The  simplest  case  is  given 
by  the  i,2-trimethylenedicarboxylic  acids,  where,  as  is  known, 
three  isomers  are  possible: 

Trans  forms:  Cis  form: 

III. 

H  CO2H          CO.,H  H  CO2H  CO2H 

J  I 

C- -C 

f\      H     /\ 
H     \|/      H 

1  I  -I 

Active.  Active.  Inactive. 


I. 

: 

C02H 

1 

c 

II. 
CO,H 

H 

\    H, 

'      H 

A\?/ 

/C0, 

Racemic  form. 

The  asymmetric  symbols,  I  and  II,  which  stand  in  the  relation 
of  object  and  image  to  each  other,  correspond  to  the  active 
forms,  wrhile  the  third  symbol  possesses  a  plane  of  symmetry, 
passing  through  the  group  CH2,  and  therefore  represents  an 
inactive  type.  In  an  analogous  way  are  related  the  hexahydro- 


144 


MODIFICATIONS    OF  INACTIVE  CONFIGURATION 


phthalic  acids,  the  hexahydroisophthalic  acids,  the  ^-tetrahydro- 
terephthalic  acids,  and  others,  in  which  the  racemic  modification 
(trans  form)  and  the  structural!}'  inactive  (cis)  form  are  known. 

41.  Differences  in  the  Properties  of  Racemically  Inactive  and 
Structurally  Inactive  Isomers. — These  have  been  observed  with 
respect  to  : 

a.  Water  of  Crystallization. — For  example  : 

Calcium  mesotartrate CaC4H4O6  -f  3CH2O  (Anschiitz)1 

Calcium  racemate CaC4H4O6  -f  4H,,O 

Calcium  d-  and  /-tartrate CaC4H4O6  -f  4H2O 

Free  mesotartaric  acid,  like  racemic  acid,  crystallizes  with 
one  molecule  of  water ;  the  inactive  tartaric  acids,  on  the 
contrary,  are  anhydrous. 

b.  Melting -Point.  — As  may  be  seen  from  the  following  obser- 
vations, the  melting-point  of  the  racemic  modification  is  gen- 
erally higher  than  that  of  the  inactive  modification,  although 
the  reverse  relation  also  appears.     In  the  last  cases,  however, 
including  erythritol  and  some  of  its  derivatives,  it  is  possible 
that  mixtures,  rather  than  racemic  compounds,  were  examined  : 


Racemic- 
ally 
inactive. 

Configu- 
rationally 
inactive. 

Diff. 
R—C 

Observer. 

Racemic  or  tartaric  acid,  anhyd. 

205-206° 
IQd 

140-143° 
1  2O 

+  64° 

1     7.1 

f  Bisch. 
\  andW.2 
Walden3 

1^4 

128 

T  /4 
1     f\A 

LTf* 

y  Q.J/  oon^ 

1    °4 

1       Afifn} 

<  < 

229 
122    127 

QQ    IOI 

i  4°\yj 

1     2/1    C 

t<     3 

T^rvthritol 

72 

yy  iui 

rTQ 

I     •'^•O 
A(\ 

/* 

8l 

I  7^ 

40 

<<     5 

°O 

Mo 

0^ 

t  < 

i  ,  2-Trimethylenedicarboxylic  acid 

y° 
i75 

*33  '34 
139 

37-5 
+  36 

+    27 

Buchner  s 

^1v) 

iy^ 

23 

J2-Tetrahydroterephthalic  acid  .  . 

220 

150-155 

43 
+  67 

v.  Baeyer9 

1  Anschiitz  :  Ann.  Chem.  (I^iebig),  326,  197. 

2  Bischoff  and  Walden  :  Ber.  d.  chem.  Ges.,  aa,  1815. 
Walden  :  Ztschr.  phys.  Chem.,  8,  467. 

/bid.,  p.  487- 

Griner  :  Compt.  rend.,  116,  723;  117,  553. 

Buchner  :  Ber.  d.  chem.  Ges.,  33,  703. 

v.  Baeyer  :  Ann.  Chem.  (Liebig),  358,  218. 

Perkin  :  J.  Chem.  Soc.,  59,  813. 

v.  Baeyer  :  Ann.  Chem.  (Uebig),  351,  308. 


MODIFICATIONS   OF    INACTIVE   CONFIGURATION  145 

c.  Solubility. — In  the  cases  which  have  been  studied,  the 
compounds  inactive  by  configuration  have  been  always  more 
readily  soluble  than  the  racemic  forms.  One  hundred  parts 
of  water  dissolve : 


Racemic- 
ally 
inactive. 

Confi^u- 
rationally 
inactive. 

Active. 

Observer. 

Tartaric  acids, 
Acid  potassium 

anhydrous  at  15° 
tartrate  at  19°  ... 

17.1     pts. 
0-555  " 

125.0  pts. 

12.5     " 

132.2  pts. 
0.535" 

Bischoff& 
Walden1 

z72Tetrahydrote 

'"  >  cold  water  .  . 

0.170  " 

2.70  "  1       —        v.Baeyer2 

d.  Constant  of  Dissociation,  K,  determined  from  electrical 
conductivity.  The  following  observations  exhibit  no  regularity 
in  this  relation: 


• 

Racemic- 
ally 
inactive. 

Configu- 
rationally 
inactive. 

Diff. 
R—C. 

Observer. 

Racemic  acid,  mesotartaric  acid, 

0.097 

0.060 

-f  0-037 

_i_  o  0068 

Walden5 

«          4 

Diethylsuccinic  acid  

O  O2d^ 

O  O'i/lt 

o  0008 

,, 

o  026 

o  006 

4< 

OOQCC 

O  OO^^ 

o 

<i         5 

1  Bischoff  and  Walden  :  Ber.  d.  chem.  Ges.,  22,  1817. 

2  v.  Baeyer:  Ann.  Chem.  (Liebig),  251,  307. 

3  Walden:    Ber.    d.    chem.    Ges.,   22,  1820;  Ostwald:  Ztschr.  phys.  Chem.,   3,  372 
Berthelot:  Ann.  chim.  phys.  [6],  23,  90. 

4  Walden:  Ztschr.  phys.  Chem.,  8,  467. 

5  Walden:  loc.  cit.,  p.  487. 


10 


PART   SECOND 


Physical  Laws  of  Circular  Polarization 


FUNDAMENTAL  RELATIONS 

With  one  and  the  same  active  body,  the  angle  through 
which  the  plane  of  transmitted  polarized  light  is  rotated, 
depends  on  the  following  three  factors  : 

1.  On  the  length  of  column. 

2.  On  the  wave  length  of  the  light  ray. 

3.  On  the  temperature  of  the  active  substance. 

42.  Relation  of  Rotation  to  Length  of  Column. — Observations  car- 
ried out  by  Biot1  in   1817  led  to  the  following  empirical  rules 
which  hold  strictly  true  for  solid  as  well  as  liquid  active  bodies  : 

1 .  The  angle  through  which    the  plane  of  polarization  of  a 
ray  of  given  wave  length    is    rotated    is  proportional  to  the 
length  of  the  active  column. 

2.  If  the  ray  is    allowed    to    pass    through    a  number  of 
separate  layers,  the  final  deviation  of  the  plane  is  equal  to  the 
sum  of  the  single  deviations  if  the  layers  or  columns  all  rotate 
in  the  same  direction,  or  equal  to  their  differences  in  case  they 
possess  opposite  rotating  powers. 

In  comparing  the  rotations  of  different  active  substances  it 
is  customary,  according  to  Biot's  suggestion,  to  reduce  the 
angle  of  rotation  of  solid  bodies  to  that  of  a  plate  of  i  mm. 
thickness  and  of  liquids  to  that  of  a  column  i  dm.  in  length. 

43.  Dependence  of  the  Angle  of  Rotation  upon  the  Wave-Length  of 
the  Ray.     Rotation  Dispersion. — The  rotation  of  the  plane  of  po- 
larization experienced  by  rays  of  different  colors  in  passing 
through  an  active  layer  is  least  for  red  and  greatest  for  violet 
light ;  it  increases,  therefore,  with  decrease  in  the  wave-length 
of  the  light.     Biot  drew  the  conclusion  from  his  measurements 
on  quartz  plates  that  the  angle  of  rotation,   a,   is  inversely 

1  Biot:  M6m.  de.  1'  Acad.,  a,  41,  91  (1817).     Ann.  chiin.  phys.  [2],  10,  63  (1819). 


ROTATION    DISPERSION  147 

proportional  to  the  square  of  the  wave-length,  A  ;  but  later  ob- 
servation showed  that  this  rule  is  only  approximately  true.  A 

n 

formula  of  the  form  a  =  A  -f  ^  ,  with  the  constants  A  and  B, 

is  likewise  inadequate  to  express  the  relation  exactly,  but 
Boltzmann1  has  shown  that  the  formula 

A        B 

(I)  «  =  V+V 

corresponds  to  the  observations  in  a  satisfactory  manner.  The 
law  of  rotation  dispersion  is  still  better  given  in  a  theoretic- 
ally derived  formula  by  E.  Lommel,2  which  contains  the  two 
constants,  a  and  A*: 


A2    T- 


(ID 


In  order  to  determine  the  constants  of  both  expressions  for 
a  given  substance,  the  angles  of  rotation,  al}  a^  a3J  ...  ob- 
served for  a  number  of  rays  of  known  wave-length, 
Aj,  A2,  A3  . .  .  must  be  found  by  measurements.  A  and  B  may 
then  be  calculated  from  each  pair  of  exact  observations,3 
and  finally  from  the  results  of  all  the  possible  combinations, 
the  mean  may  be  taken,  or  the  method  of  least  squares  may 
be  applied.  In  order  to  obtain  convenient  numerical  values, 
the  wave-lengths  are  best  expressed  in  millimeters,  for  example, 
hc=  0.0006562. 

The  formulas  (I)  and  (II)  may  be  employed  also  to  deter- 
mine the  wave-length  of  any  kind  of  light  by  measuring  the 

1  Boltzmann:  Pogg.  Ann.,  Jubelb.  (1874),  p.  128. 

2  E.  lyommel:  Theorie  der  Drehung  der  Polarisationsebene,  Wied.  Ann.,  14,  523 
(1881);    Das  Gesetz  der  Rotations-dispersion,  Wied.  Ann.,  20,  579  (1883). 

3  From  the  Boltzmann  equations  : 

__A_        B_        and  __^4    ,    B_f 

there  follow  : 

A  = and  B  =  " 

I  I  I 

~\  t    ~\  4  ifa     TfJ"  1~2      \4 

/Vr    A.tl          A.n    Aj  AIt    A, 


148  PHYSICAL   LAWS   OF    CIRCULAR    POLARIZATION 

angle  of  rotation  produced  in  it  by  any  substance,  the  rotation 
dispersion  of  which   is   known  ;  for  example,   quartz.     If  we 

A        B 
apply  the  Boltzmann  formula,  a  =-.  ~TT  ~l~  "TT  >  and  take 

A  B 

-  =  a     and      -  =  b, 
a  oc 

we  have  next  to  determine  the  value, 
a 


from  which  the  desired  wave-length,   expressed  in  millionths 
of  a  millimeter  (A</0,  is  given  by 


if  the  millimeter  scale  wave-lengths  are  used  in  calculating  A 
and  B. 

From  the  L,ommel  formula  there  follows: 


2  or 

The  methods  by  which  the  angles  of  rotation  for  a  number 
of  rays  of  known  wave-length  were  measured  and  from  this 
the  rotation  dispersion  of  a  substance  determined  are  described 
in  Part  IV.  Observations  thus  far  carried  out  are  based 
either  on  the  Fraunhofer  sun  lines  or  on  the  lithium,  thallium, 
or  sodium  line,  or  finally  on  certain  kinds  of  approximately 
monochromatic  light  obtained  by  so-called  ray  filters.  Up  to 
the  present  time  exact  data  have  been  given  mainly  for  the 
following  substances: 

44.  Rotation  Dispersion  of  Crystals,  i.  Quartz. — Several  series 
of  observations  on  this  substance  are  on  record,  among  which 
the  older  ones  by  Broch1  ( 1852) ,  Stefan2  (1864) ,  Soret  and  Sara- 
sin3  ( 1876) ,  may  be  excluded  as  the  influence  of  temperature  was 
not  sufficiently  considered,  in  reference  to  which  it  was  first 
shown  by  Dubrunfaut4  and  later  by  v.  Lang5  that  it  exercises  a 
not  unimportant  effect  on  the  rotating  power  of  quartz.  Soret 

1  Broch:  Dove's  Repert.  d.  Phys.,  7,  115;  Ann.  chim.  phys.  [3],  34,  119  (1852). 

8  Stefan:  Wien.  Ber.,  50,  II.;  Pogg.  Ann.,  iaa,  631,  1864. 

3  Soret  and  Sarasin:  Pogg.  Ann.,  157,  447  (1876). 

«  Dubrunfaut:  Compt.  rend.,  33,  44  (1846). 

*  v.  Lang:  Wien.  Ber.,  71,  II,  707  (1875).     Pogg.  Ann.,  156,  422  (1875). 


ROTATION   DISPERSION   OF   QUARTZ 


149 


and  Sarasin1  then  published  two  new  series  of  observations  which 
are  based  accurately  on  a  temperature  of  20°,  and  which  may 
now  be  looked  upon  as  the  most  reliable.  These  observations 
cover  29  lines,  from  wave-length  214—760  ////;  those  referring 
to  the  visible  lines  from  A  to  H  are  given  in  the  table  below. 
A  quartz  plate  having  a  thickness  of  30  mm.  was  used  in  the 
observations  under  I,  while  a  plate  with  a  thickness  of  60  mm. 
served  for  the  observations  under  II.  Some  exact  observations 
by  V.  v.  Lang  are  given  also.2 

QUARTZ.    ANGLE  OF  ROTATION  FOR  i  MM. 


Observed  by 

Fraunhofer 
lines. 

Wave-lengths 
according  to 
Angstrom 

Soret  and  Sarasin. 
Temperature  20°. 

Mean. 

Calculated  by 
the  formula 

\  in  fjifi. 

of  lyOnimcl. 

I. 

ii. 

A 

760.4 

I2.66803 

I2.62801        12.65°          12.78° 

a 

718.36 

14.304 

14.298 

14.30             14.37 

B 

686.71 

i  ^.746 

15.75              !5.78 

C 

656.21 

17.318 

17.307 

17.31              17-34 

A 

589.513 

21.684 

21.696 

21.69             21.70 

A 

588.912 

21.727 

21.724 

21.725           21.74 

E 

526.913 

27-543 

27.537 

27.54             27.51 

F 

486.074 

32.773 

32.749 

32.76             32.69 

G 

430./25 

42.604* 

42.568s 

42.59 

42.51 

h 

410.12 

47.48i 

47.492 

47-49           47-36 

H 

396.81 

5LI933 

51.182* 

51.19           50.97 

v.  Lang. 

Lines. 

\ 

v.  Lang 

Rays. 

A 

Temp.  o°. 

Temp.  20*. 

C 

656.21 

17.299° 

Li 

670.8 

16.402° 

16.460° 

D 

589.21 

21.727             Na 

589.2 

21.597 

21.660 

F 

486.07 

32.722             77 

535-  14 

26.533 

26.61  15 

1  Soret  and  Sarasin:  Compt.  rend.,  95,  635  (1882); 

2  V.  v.  Lang:  Wien.  Ber.,  74,  II.,  209  (1876). 


Arch  de  Geneve,  8,  5,  97,  201. 


Further  measurements  have  been  made  by  Wasastjerna  (Wied.  Beibl.,  15,  in 
(1891)  )  but  the  temperatures  are  not  given.  The  rotation  of  infra  red  rays  in  quartz 
has  been  investigated  by  P.  Desains  (Compt.  rend.,  84,  1056(1877));  Mussel  (Wied- 
Ann.,  43,  498  (1891)  )  and  Carvallo  (Compt.  rend.,  114,  288;  Ann.  chim.  phys.  [6],  26, 
113  (1892)  ).  The  observations  of  Soret  and  Sarasin  extend  to  the  ultraviolet  rays. 

3  Observations  of  less  certainty. 

4  According  to  Kayser  (Landolt-Bornstein,  Phys.  chem.  Tab.,  p.  383). 

5  Calculated  from  the  data  for  o°  by  means  of  Gumlich's  temperature  formula. 


150          PHYSICAL   LAWS   OF    CIRCULAR    POLARIZATION 

The  observations  of  Soret  and  Sarasin  may  be  expressed  by 
the  Boltzmann  dispersion  formula  with  the  constants: 

_  7.108  2930       0.147  7086 
ioU'  lo'U4     ' 

(X  in  millimeters) 

and  also  by  the  formula  of  Lommel: 


a  == 


in  which 

log  a  =  0.855  5912,  log  A;  =  7.935  1257  —10. 
(X  in  thousandths  of  a  millimeter  /*) 

The  angles  of  rotation  calculated  in  this  way  are  given  in 
the  last  table. 

Rotation  of  Quartz  for  Sodium  Light.1 — Among  observations 
in  this  direction,  those  recently  carried  out  by  Gumlich"  in  the 
physikalisch-technischen  Reichsanstalt  must  be  considered  the 
most  accurate.  In  these  investigations,  about  twelve  right- 
and  left-rotating  round  quartz  plates,  50  to  60  mm.  in 
diameter,  from  1.2  to  10.5  mm.  in  thickness  (measured  to 
o.i  //),  and,  as  nearly  as  possible,  with  plane  parallel  surfaces 
(maximum  difference  in  thickness  0.5^)  were  used.  They 
were  ground  perpendicularly  to  the  optical  axis  as  perfectly  as 
possible,  and  special  measurements  showed  that  the  axis  error, 
that  is,  the  angle  between  the  optical  axis  and  normal  to  the 
plate  surface,  was  never  more  than  16'.  The  sodium  light 
employed  (from  sticks  of  soda  in  oxy hydrogen  lamp)  passed 
first  through  prisms3  and  a  slit,  the  latter  of  which  served  to  cut 
out  foreign  rays.  The  determination  of  the  angle  of  rotation 
was  made  by  aid  of  a  Lippich  half -shadow  apparatus  and  in 
order  to  eliminate  the  error  from  lack  of  perfect  parallelism  in 
the  plates,  the  latter  were  adjusted  in  four  positions,  90°  apart. 
To  determine  the  effect  of  temperature,  the  measurements 
were  made  in  a  room,  the  temperature  of  which  could  be 

i  See  later,  Part  IV. 

*  E.     Gumlich  :     Wissenschaftl.      Abhandlungen     der     Physikalisch-technischen 
Reichsanstalt,  a,  201  (1895);     Ztschr.  fur  Instruinentenkunde,  1896,  p.  97. 

*  Two  Wernicke  hollow  prisms  containing  ethyl  cinnaniatc. 


ROTATION   OF   QUARTZ 


varied  between  o°  and  30°.  The  investigations  led  to  the 
following  results  : 

Pure  sodium   light   is  rotated  by  a  quartz  plate,    i  mm.  in 
.  thickness  at  a  temperature  of  20°, 

21.7182°  rfc  0.0005, 

provided  the  light  passes  through  the  plate  exactly  in  the 
direction  of  the  optical  axis.  Under  other  conditions  the 
rotation  is  somewhat  larger  ;  when  the  plates  were  set  exactly 
perpendicular  to  the  entering  light,  the  angle  was,  on  account 
of  the  axis  error,  in  the  mean  21.7223°  ±:  o.ooio. 

The  angles  of  rotation  for  right-  and  left-handed  plates 
were  found  to  be  exactly  the  same,  and  it  was  further  found 
that  quartzes  from  different  localities  (Brazil,  Japan,  Switzer- 
land) showed  no  appreciable  variations. 

A  difference  in  the  behavior  of  unequally  intense  lights 
(oxy hydrogen  lamp,  L/andolt  lamp)  could  not  be  recognized 
with  certainty  when  the  purification  of  the  light  from  foreign 
rays  was  effected  by  the  spectrum  method.  But  when  this 
was  done  by  other  methods  (Lippich's  ray  filter  with  potassium 
dichromate  and  uranous  sulphate)  appreciable  differences 
appeared. 

Other  observers  have  found  earlier  the  following  figures  as 
expressing  the  rotation  of  quartz  for  sodium  light  at  20°  :  l 


Broch(i846) 21.67. 

Stefan  ( 1864) 2 1.  67. 

Wild    (1864) 21.  67. 

Mascart  (1872) 21.746. 

v.   Lang  (1875) 21.661. 


v.Lang    (1876) 21.724. 

Joubert  (1878) 21.723. 

Soret  and  Sarasin  (1882).   21.723. 

Soret  and  Guye  (1892/3).   21.  718 

and  729. 


Effect  of  Temperature  on  the  Rotating  Power  of  Quartz. — 
This  is  exerted,  as  first  shown  by  v.  Lang,2  in  the  sense  that 
with  an  increase  of  temperature,  an  increase  in  the  rotation 
follows.  The  increase  may  be  expressed  by  the  following 
formulas  in  which  at  represents  the  angle  at  a  higher  tem- 
perature, and  or0  that  at  a  lower  temperature. 

Within  mean  temperatures  Gumlich3  found  for  right-  and 
left-rotating  quartz  and  sodium  light  : 

1  See  Gumlich  :  Loc.  cit.,  p.  246. 

2  v.  Lang  :  Pogg.  Ann.,  156,  422  (1875). 

3  Gumlich  :  Loc.  cit.,  p.  230. 


152 


PHYSICAL   LAWS   OF   CIRCULAR    POLARIZATION 


=  ao  (i  4-  Q.o.,144  t  +  o.o6i46  t.2)  \ 


(        o°  and  -$o° 


and  for  smaller  differences  in  temperature  : 
at  =  aQ  (i  +  0.031470 

Other  observers  have  given  coefficients  which  agree  with  this, 
thus: 


v.  Lang,1   a  =  OQ  (i  -f-  0.03149  /),  holding  between   20°  and  100°, 

Sohncke,2  a,  =  a,,  (i  -f-  0.03148  /),         "  "          23°     "    100°, 

Joubert,3    <*/=  ao  C1  +  °-°3T49  0>         "  "  °°     "    Joo0, 

o.t=  a0  (i  -f  0.031463  1  +  o.o7329  /»)         —20°     "    100°. 

For  low  temperatures,  Soret  and  Guye4  found  : 

«'  +  °o  C1  -f  0.031326  /),  holding  between  —55°  and  +23°, 
<*'-h«o  (i  +  0.031265  /),        "  —72°"     +  18°. 

According  to  Le  Chatelier5  the  rotation  increases  irregularly 
at  high  temperatures.  Based  on  observations  made  by  him, 
that  quartz  undergoes  a  sudden  change  in  dimensions  at  570°, 
he  calculates  the  following  formulas  : 

Between  o°  and  570°  : 

«/  =  °v  (i  +  o.o496  /  +  o.o62i7  f1}. 

At  570°  there  is  an  increase,  d  a  =  0.043  ao- 

Above  570°  this  expression  holds  :6 

a  =  u0  (1.165  +  o.o4is  (t  —  570°)). 

The  angles  of  rotation  found  by  Le  Chatelier  are  : 


/ 

Diff. 

»ry 

^P 

A  =  518 

A  =  500 

A  =  448  MM 
'     Mg-line 

20° 

17-25 

21.72          28.62 

30.78 

39-24 

280 

260 

18.06 

22.68          29.82 

32.16 

40.80 

415 

135 

18.60 

23.40          30.60 

32.90 

42.OO 

560 

145 

19.38 

24.30       32.04 

34.56] 

44.10 

600 

40 

20.10            25.26       .33.18         35.76 

45.60 

900 

300 



25.32 

[33.24 

36.00 

45-84 

In  these  figures  the  sudden  strong  increase  between   560' 
and  600°  may  be  recognized. 


v.  Lang  :  IJDC.  cit. 

Sohncke  :  Wied.  Ann.,  3,  516. 

Joubert :  Compt.  rend.,  87,  497. 

Soret  and  Guye  :  Ibid.,  115,  1295  ;  116,  75. 

Le  Chatelier  :  Ibid.,  109,  244  (1889). 

Confirmed  by  Gumlich  :  I^oc.  cit.,  p.  230. 


ROTATION   DISPERSION   OF   CRYSTALS 


153 


According  to  v.  Lang,1  Sohncke2  and  Le  Chatelier3  the  tem- 
perature coefficient  remains  constant  for  rays  of  all  wave- 
lengths, but  more  exact  measurement  would  probably  disclose 
differences  here. 

The  rotation  of  quartz  at  low  temperatures  has  been  care- 
fully investigated  by  Soret  and  Guye.4  For  a  plate  having  the 
thickness  of  i  mm.  at  12°  the  following  rotations  of  the 
sodium  ray  wrere  found: 


t=  —71.5        -55-3°     -42.3' 


o° 
21.655 


+  17-7° 
21.719 


+  22.7C, 

=     51.470         21.505         21.537         21.655         21.719         21.730. 

These  observations  may  be  expressed  with  satisfactory 
accuracy  by  the  interpolation  formula  of  Joubert  given  above. 

2.  Sodium  Chlorate,  NaClO3.— The  angles  of  rotation  of  the 
regular  crystals  were  determined  by  Guye5  and  also  by 
Sohncke6  for  different  rays  and  temperatures.  Based  on  a 
thickness  of  i  mm.  these  values  were  found: 


Guye. 

Line. 

Guye. 
a  at  2O° 

Sohncke. 

a  at  21°. 

Relation  of 
quartz  to 
sodium 

chlorate. 

a 

2.070° 



6.908 

B 

2.273 

2.38° 

6.927 

C 

2.503 

2.52 

6.915 

D, 

3.128 

D  3.16                 6.9361 

A 

3-I32 

6.9362 

B 

3-944 

3.96 

6.982 

F 

4.670 

4.61 

7.013 

G 

6.005 

5-89 

7.089 

h 

6.675 

— 

7.H5 

H 

7-174 

6.86 

7.134 

For  increase  of  rotation  with  temperature  : 

Guye.  .  ...   a,  =  a0  (i   -f  0.000586  /),  for  t  =  -f    5  to 
Sohncke...  a,  =  o0  (i  +  0.00061  /),       "   *?=+  l6  " 


28 


1  Loc.  cit. 

2  Loc.  cit. 

3  Loc.  cit. 

*  Soret  and  Guye:  Arch.  sc.  phys.  et.  nat.  Geneve  [3],  29,  243  (1893). 
5  Guye:  Arch,   de  Geneve,    [3"],  22,  130(1889).    The  values  for  fourteen  ultraviolet 
lines  are  omitted  from  the  table. 

«  Sohncke:  Wied.  Ann.,  3,  529  (1878). 


154  PHYSICAL   LAWS   OF   CIRCULAR    POLARIZATION 

Among  other  active  crystals  the  following  have  been  inves- 
tigated with  respect  to  their  rotating  power: 

Sodium  periodate,  NaIO4  -f-  3H2O. 
Potassium  dithionate,  K2S2O6. 
Lead  dithionate,  PbS2O6  -f-  4H2O. 

The  data  for  these  have  already  been  given  in  §  6. 

45.  Rotation  Dispersion  of  Liquid  and  Dissolved  Substances. — 
As  yet  there  are  but  relatively  few  observations  on  record  in 
this  direction,  of  which  the  older  ones  (on  cane  sugar,  santonin, 
turpentine,  bile  acids,  etc. )  were  made  by  the  Broch  method1 
and  are  based  on  the  Fraunhofer  lines,  while  the  later  obser- 
vations have  been  made  by  the  ray  filter  method.1  The 
numerical  data  will  be  found  in  part  VI,  "Constants  of 
Rotation." 

With  substances  which  are  in  themselves  liquid  the  rotation, 
as  far  as  is  known,  shows  a  normal  behavior  ;  that  is,  the 
amount  of  rotation  increases  with  the  refrangibility  of  the 
light.  This  is  the  case  with  the  terpenes  and  also  in  a  series 
of  derivatives  of  amyl  alcohol,  lately  studied  by  Guye  and 
Jordan,"  which  all  have  the  simple  molecular  \veight.3  These 
bodies  possess  very  different  dispersive  powers,  which  for  each 
substance  is  a  characteristic  constant  and  may  be  expressed  by 
the  difference  [#]  violet  —  [^]red,  and  designated  as  the  specific 
rotation  dispersion. 

The  same  normal  behavior  is  observed  with  many  substances 
in  solution  (cane  sugar,  dextrose,  santonin  and  derivatives,  bile 
acids  and  others). 

The  following  table  will  serve  for  the  comparison  of  the 
dispersive  powers  of  different  substances  with  each  other,  and 
also  with  that  of  quartz,  the  figures  referring  to  the  rotations 
for  the  lines,  B,  C,  D,  E,  /^and  G  :4 

1  See  Part  IV:  Determination  of  Rotation  Dispersion. 
8  Guye  and  Jordan:  Cotnpt.  rend.,  122,  883  (1896). 

3  Ramsay  and  Shields:  Ztschr.  phys.  Chem.,  12,  433. 

4  Cane  sugar  in  water,/  =  101030.     Stefan  :  Wien.  Sitzber,  52,  II.  486.     Cholalic 
acid  in  alcohol,  c  =  3.    Hoppe-Seyler :  J.  prakt.  Chem.,    [i],  89,  257.    Cholesterol  in 
petroleum,  c  =  10.    Lindenmeyer  :  J.  prakt.  Chem.,  [i],  90,  323.     Turpentine  oil  and 
lemon  oil,  G.  Wiedemann  :  Pogg.  Ann.,  82,  222.     Santonin  in  chloroform,  c  =31090. 
Nasini :  Accad.  d.  I«incei,  [3],  13,  (1882). 


ROTATION    DISPERSION   OF   LIQUIDS,    ETC.  155 

BCD  E  F  G 

Quartz a    i  mm  ±     15.75     17.31     21.71  27.54  32.76  42.59 

Cane-sugar [a]  i  dm    -j-    47.56     52.70     66.41  84.56  101.18  131.96 

Cholalic  acid-.,  [a]     "        +    28.2       30.1       33.9  44.7  52.7  67.7 

Cholesterol [a]     "          -    20.63     25.54     31.59  39.91  48.65  62.37 

Turpentine  oil ..  a       "           -    21.5       23.4       29.3  36.8  43.6  55.9 

Lemon   oil a       "        +    34.0       37.9       48.5  63.3  77.5  106.0 

Santonin [a]     "        +484.0  549.0    754.0  1088.0  1444.0  .... 

If  we  calculate  from  these  figures  how  much  more  strongly 
the  rays  C,  D,  E,  F  and  G  are  rotated  than  is  the  ray  B,  the 
following  so-called  coefficients  of  dispersion  result  : 

B         C  D          E  F          G 


Quartz i         i  .09 

Cane-sugar 

Cholalic  acid 

Cholesterol . . . 


Terpentine  oil 
Lemon  oil 
Santonin 


i.  n 
1.07 
1.24 
1.09 
i.  ii 


,1.1 


.38  1.75  2.08  2.70 

.40  1.78  2.13  2.77 

.20  1.59  1.87  2.40 

.53  1.93  2.36  3.02 

.36  1.71  2.03  2.60 

.43  1.86  2.28  3.12 

.56  2.25  2.98 

From  this,  it  appears  that  the  relation  between  quartz  and 
cane-sugar  is  nearly  constant,  these  substances  having  nearly 
the  same  rotation  dispersion,  while  other  bodies  disperse  either 
more  or  less  strongly  than  quartz.  This  fact  is  applied  in  the 
construction  of  polarimeters  with  quartz-wedge  compensation 
(Soleil's  color  saccharimeter  and  the  Schmidt  and  Haensch  half 
shadow  saccharimeter),  when,  as  is  usual,  white  light  is 
employed.  The  construction  of  these  instruments  presupposes 
equality  in  the  dispersive  power  of  the  active  substance 
investigated  with  that  of  the  quartz- wredges,  and,  therefore, 
substances  which  depart  much  from  this  relation  cannot  be 
used  or  studied  with  them. 

In  studying  the  dispersion  ratio  between  cane  sugar  and 
quartz  some  new  observations  of  Seyrfart1  may  be  used  which 
are  based  on  the  rotation  of  sugar  solutions  for  seven  artificial 
spectral  lines.  If,  as  a  basis,  a  solution  be  taken  which  rotates 
the  red  hydrogen  line  (Ha)  through  the  same  angle  as  a  quartz 
plate  i  mm.  in  thickness,  that  is  17.31°,  then  for  the  other 
colored  rays  the  following  angles  are  found  which  are  given 
along  with  the  angles  for  quartz  for  comparison.  (For  some 
of  the  last,  marked  with  a  *,  the  values  were  found  from  the 

1  Seyffart:  Wied.  Ann.,  41,  113,  128  (1890). 


156 


PHYSICAL   LAWS   OF   CIRCULAR    POLARIZATION 


above  quoted  measurements  of  Soret  and  Sarasin  by  aid  of  the 
Boltzmann  interpolation  formula.) 


Angle  of  rotation. 


Color.  Line. 

Red  ............  //a(C) 

Yellow  .........  Na(D) 

Green  ..........  77 

Greenish-blue  ..  ffp(F) 

Blue  ...........  Sr 


Wave-length. 

Quartz. 

Cane-sugar. 

Difference. 

656.  2MM 

17.31° 

I7.3I0 

— 

589.2 

21.72 

21.78 

0.06° 

535-0 

26.64* 

26.81 

0.17 

486.1 

32.76 

32.98 

O.22 

460.7 

36.77* 

37.18 

0.41 

434-1 

41.88* 

42.44 

0.56 

420.2 

45-oo* 

45.78 

0.78 

Violet  ..........  Rbn 

From  these  figures  the  following  dispersion  coefficients  are 
calculated  : 

Ho.       Na  71  H$  Sr  Hy         Rbn 

Quartz  ......    I         1.255         1.539         I-893        2-I24        2.419        2.600 

Cane-sugar.,   i         1.258        1.549        1-905        2.148        2.452        2.645 

It  is  seen  that  the  dispersive  power  of  sugar  exceeds  that  of 
quartz,  but  the  difference  is  appreciable  only  in  case  of  the 
blue  and  violet  rays,  which,  on  account  of  their  low  luminosity, 
are  but  little  used  in  the  quartz  wedge  saccharimeters. 

The  dependence  of  the  specific  rotation  of  cane-sugar  on 
the  wave-length,  A,  of  the  light  employed,  may  be  expressed 
by  a  formula  derived  by  Seyffart1  from  observations  on  a  20  per 
cent,  solution.  A  is  expressed  in  millimeters. 

iyu  _  2.  16036     5.47276 
l^/5         iols.A* 

As  examples  of  substances  with  larger  dispersion,  coupled 
with  high  specific  rotation,  we  have  the  following  santonin 
bodies,  investigated  by  Nasini  :* 


Santonide                   Parasantonide 

Fraun- 

Wave- 
length. 

Santonin 

Ci5HigO3 

Solution  in  alcohol. 

ClsHjgOg                                       CiftHjgOg 

Solution   in  chloro-     Solution  in  chloro- 

fomi  .                                               f  nrtn 

hofer 

Angstrom. 

c  —  1.782 

c  =  3  to  30 

c  _  -  to'cO 

lines. 

MM 

t  =  2Q° 

/=20° 

/  =  20° 

to 

•] 

w 

B 

686.7 

—  110.4° 

1.  00 

+      484° 

I.OO 

+  580.5° 

I.OO 

C 
D 

656.2 
589.2 

118.8 

161.0 

1.08 
1.46 

549 
754 

i? 

655.6 
891.7 

1.13 

i-54 

E 

526.9 

222.6 

2.02 

1088 

2.25 

1264 

2.18 

b. 

518.3 

237-  I 

2-15 

1148 

2.37 

1334 

2.30 

F 

486.1 

261.7 

2-37 

1444 

2.98 

1666 

2.87 

e 

438.3 

380.0 

3-44 

2201        4.55 

2510 

4-32 

g 

422.6 

— 

2610     i  5.39 

2963 

5.10 

Seyffart :  Loc.  cit. 

Nasini :  Accad.  d.  Uncei,  Cl.  sc.  fis.  mat.  e.  nat,  [3],  13,  18*2. 


ROTATION    DISPERSION    OF  LIQUIDS,    ETC  157 

If  an  active  body  is  dissolved  in  different  liquids,  the 
rotation  dispersion  remains  the  same  in  all  the  solutions.  This 
was  shown  by  Gennari1  with  mixtures  of  nicotine  with  water, 
methyl  alcohol,  ethyl  alcohol  and  benzene. 

Finally,  as  regards  the  effect  of  temperature  on  rotation  dis- 
persion, Gernez2  has  observed  that  the  dispersion  suffers  no 
change  in  turpentine  oil,  orange  oil,  bitter  orange  oil  and  cam- 
phor, and  not  even  when,  by  aid  of  heat,  the  substances  are 
brought  into  the  condition  of  vapor. 

46.  Anomalous  Rotation  Dispersion. — With  certain  substances 
in  solution  the  phenomenon  is  observed  that  the  rotation  of  the 
plane  of  polarization  does  not  change  regularly  with  increasing 
refrangibility  (or  decreasing  wave-length)  of  the  rays,  but 
that  for  some  color  lying  between  the  red  and  violet  ends  of 
the  spectrum  it  has  a  maximum,  or,  also,  a  minimum. 
Further  than  this,  the  rotation  may  be  the  same  for  a  number 
of  different  rays.  Such  anomalies,  which,  as  is  known,  may 
appear  also  in  respect  to  refractive  dispersion  have  been 
observed  in  the  following  substances. 

d-  Tartaric  Add, — The  irregularities  in  the  rotation  dispersion 
of  this  substance  were  discovered  by  Biot3  and  later  investi- 
gated by  Arndtsen.4  The  latter  determined  the  increase  in 
the  specific  rotation  of  the  acid  in  solutions  of  decreasing  per- 
centage strength,  for  different  Fraunhofer  lines,  employing 
the  method  of  Broch,  and  calculated  the  following  interpolation 
formulas,  holding  for  a  temperature  of  24°,  q  representing  the 
percentage  amount  of  water  present: 

Spectral        Wave-length, 
lines.  fifji 

C  656.2  [a]  =  -f  2.748  -f  0.0945  q 

D  589-2  [a]  =  -r  1.950  +  0.1303? 

E  526.9  [a]  =  +  0.153  -f  O.I75I  q 

dl  518.3  [a]  =  —  0.832  +  0.1915  q 

F  486.1  [a]  =    -  3.598  +  0.2398  q 

e  438.3  [«3  =    -  9-657  +  0.3144  q 

If  from  these  formulas,  which  hold  to  q  =  40  (the  strongest 

solution  of  tartaric  acid  which  can  be  made  at  24°  contains  60 

1  Gennari  :  Ztschr.  phys.  Chern.,  19,  130  (1896). 
Gernez  :  Ann.  de  1'ecole  norm.,  i,  i. 

3  Biot.  Mem.  del'Acad.,  15,  93  (1838). 

4  Arndtsen  :  Ann.  chim.  phys.,  (3),  54,  403.     Pogg.  Ann.,  105,  31*. 


158 


PHYSICAL   LAWS   OF   CIRCULAR    POLARIZATION 


per  cent,  of  the  acid),  but  which  certainly  apply  for  q  =  30, 
we  calculate  the  specific  rotations  of  solutions  containing  from 
30  to  90  per  cent,  of  water,  we  obtain  the  following  numbers, 
given  in  order  of  increasing  concentration: 


In  100  parts  of 
solution. 

Red. 

Yellow. 

Green. 

Green. 

Greenish 
blue. 

Blue. 

Water 
9 

Tartaric 
acid. 

We 

[«]* 

M* 

a]* 

0> 

[«3. 

9° 

10 

11.25° 

13-68° 

15.92° 

16.40° 

I7.980 

18.64° 

80 

20            10.30 

12.37 

14.16 

14.49            15-59*         15-49 

70 

3°           9-36 

11.07 

i?.4r 

12.57            I3-I9*         12.35 

60 

40 

8.42 

9-77 

10.66 

10.66 

10.79*         9-21 

50 

50 

7-47 

8.47 

8.91* 

8.74           8.39           6.06 

40 

60 

6-53 

7.16* 

7.16* 

6.83            5.99            2.92 

30 

70 

5.58           5-86*         5-41 

4.91            3.60       —0.23 

From  this  table  it  is  evident  that  for  some  particular  color 
each  solution  shows  a  maximum  in  its  rotating  power  which  is 
indicated  by  a  *.  For  the  weakest  solution,  with  ten  per 
cent,  of  tartaric  acid,  the  maximum  occurs  normally  at  the 
color  of  greatest  refrangibility,  e\  but  with  increase  of  con- 
centration it  passes  gradually  toward  the  red  end  of  the 
spectrum,  the  50  per  cent,  solution  exhibiting  the  maximum 
rotation  for  the  green  ray,  and  the  70  per  cent,  .solution  for  the 
yellow.  In  these  cases  the  rotation,  after  passing  the  maxi- 
mum point,  decreases  with  increase  in  refrangibility  and 
becomes  finally  negative  for  blue  light  with  the  most  concen- 
trated solution.  This  solution  must  therefore  be  perfectly 
inactive  for  some  color  between  F  and  e.  It  is  also  evident 
that  for  certain  concentrations  different  rays  are  rotated 
through  the  same  number  of  degrees;  thus  the  specific  rota- 
tion of  the  solution  with  40  per  cent,  of  acid  is  10.66°  for  E 
as  well  as  for  b,  and  for  the  60  per  cent,  solution  it  is  the  same 
for  D  and  E,  vis.,  7.16°. 

The  left-hand  rotation  which  with  a  70  per  cent,  solution 
appears  for  blue  light,  would  increase  and  show  even  with  the 
less  refrangible  rays,  if  it  were  possible  to  pass  to  more  con- 
centrated solutions.  The  anhydrous  acid,  whose  specific 
rotation  is  expressed  by  the  first  constants  of  the  Arndtsen 


ROTATION    DISPERSION   OF   LIQUIDS,    ETC.  159 

formulas,  must,  as  shown  by  the  sign,  exhibit  right-hand 
rotation  for  the  rays  C,  D  and  E,  and  left-hand  rotation  for 
b,  P  and  e.  In  fact,  Biot1  was  able  to  observe  such  opposite 
rotation  with  plates  made  by  pouring  a  mixture  of  tartaric  acid 
melted  with  a  little  water  ;  and  Arndtsen2  found  that  left 
rotation  for  the  strongly  refrangible  rays  is  shown  when  con- 
centrated alcoholic  solutions  of  the  acid  are  used. 

The  anomalies  in  the  rotation  dispersion  of  tartaric  acid 
disappear  when  the  solutions  are  examined  at  a  higher  tem- 
perature (Krecke),3  or  when  a  little  boric  acid  is  added  (Biot). 
They  are  not  shown  with  the  salts  of  tartaric  acid  (Biot), 
which  fact  has  recently  been  confirmed  by  Rimbach4  in  the 
case  of  rubidium  tartrate. 

Malic  Acid. — The  rotating  power  for  different  kinds  of  light 
has  been  investigated  by  B.  A.  Woringer3  by  aid  of  the  ray- 
filter  method,  and  using  solutions,  the  amount  of  water  in 
which,  q,  varied  from  49  per  cent,  to  93  per  cent.  The  follow- 
ing interpolation  formulas  were  derived,  based  on  a  tem- 
perature of  20°  : 

Red \  =  665.9  W>  [a]  =    4-605  —  0.0709  q 

Yellow "-=5919"  "        =    6.544  —  0.0957" 

Green "=533.0"  "        =    8.349  —  0.1128" 

Light  blue "=  488.5  "  "      =10.121—0.1298" 

Dark  blue "=448.2  "  "      =14.971  — 0.1730" 

The  specific  rotations  calculated  from  these  are  : 

TABLE  I. 

Malic  acid.          Water. 

Dark- 


P 

Q 

.K.CU 

i  e 

1OW 

ij 

re 

en 

bh 

ie 

blue 

50 

5° 

4-  1.06 

+  I 

.76 

+ 

2.71 

+  3 

.63 

+  6.33 

40 

60 

-fo.35 

+  0 

81 

4- 

I. 

58 

+  2 

•33 

+  4-59 

30 

70 

—  0.56 

-r  0.15 

- 

0 

45 

+   I 

•03 

4-  2.86 

20 

80 

-  1.07 

—  i 

ii* 

— 

0 

67 

—  O 

.27 

4-  1.13 

IO 

90 

-1.78 

—  2.07* 

I. 

80 

—  I 

.56 

-0.59 

8 

92 

-1.92 

—  2.26* 

2. 

03 

—   I 

•  84 

-0.95 

5 

95 

—  2.13 

-  2.55* 

2. 

37 

—  2 

•23 

-  1-47 

1  Biot  :  Ann.chim.  phys  ,  [3],  28,  351. 

2  Arndtsen:  Ann.  chim.  phys.,   [3],  54,  415. 

3  Krecke:  Arch.  Neerland.,  7,  (1872). 

4  Rimbach  :  Ztschr.  phys.  Chem  ,  16,  671. 

5  Woringer :  Investigations  in  the  author's  laboratory,    not  yet  published  (1898). 


i6o 


PHYSICAL   LAWS   OF   CIRCULAR    POLARIZATION 


In  another  series  of  observations  carried  out  by  Nasini  and 
Gennari,1  in  which  the  ray-filter  method  was  employed,  the 
yellow  light,  however,  being  that  of  the  sodium  flame,  the 
following  specific  rotations,  for  a  temperature  of  20°  were 

obtained  : 

TABLE  II. 


No. 

4* 

P 

q 

[«1«* 

[  ]* 

Mir 

[•]• 

E«J- 

i 

1.3454 

72.79 

27.21 

+  1.80° 

+  2.86° 

+   3-90° 

+  5-20° 

+  6.39° 

2 

1.2723 

59.02 

40.98 

+  1-35 

+  2.08 

+  3-°5 

+  4.21 

-f  5.63 

3 

1.1861 

42.80 

57-20 

+  0.19 

+  0.55 

-f  1.18 

+  2.08 

+  3-29 

4 

1.1423 

34-27 

65-73 

-  0.18 

+  0.07 

+  o.5i 

+  1.64 

+    2.20 

5 

LI395 

33-24 

66.76 

-  0.41 

-  0.31 

+  0.07 

+  0.46 

-f  0.86 

6 

1.1239 

30.02 

69.98 

-  0.51 

-  0.42 

-  0.05 

+  0.29 

+  0.72 

7 

1.1193 

28.72 

71.28 

-  0.79 

—  0.67 

—  0.46 

-   0.22 

+  0.29 

8 

1.1034 

25.67 

74.33 

-  o.94 

-  0.81 

-  0.69 

-  0-39 

+  0.14 

9 

1.0663;  16.84 

83.16    -  1.07 

-  1.28* 

-  1-05 

-  0.62 

0.00 

10 

1.0635!  16.24 

83.76    -  1.28 

-  1.46* 

-  1.30 

—  0.91 

-0.36 

ii 

1.0304     8.23 

91.77 

-  1.09 

-  1.09 

-  i  .08 

-  1.09 

-  1.08 

12 

1.0156 

4.61 

95.39 

-  1.87 

-  1.17 

-  2.56 

-  2.45 

-  2.51 

From  these  two  tables  the  following  appears : 

1.  Concentrated  solutions  of  malic  acid,   with  amounts  of 
water  varying  from  27  to  60  per  cent.,  exhibit  right  hand  rota- 
tion for  all  colors,  which  increases  normally  with  the  refrangi- 
bility  of  the  rays. 

2.  In  solutions  with  q  =  66  to  75  per  cent.  (4  to  8  in  Table 
II)  the  less  refrangible  rays  rotate  to  the  left  and  the  stronger 
to  the  right.     The  point  of  inactivity  which  is  passed  here 
moves,  with  increasing  dilution,  toward  the  violet  end  of  the 
spectrum. 

3.  Anomalous   dispersion  is  shown  in  solutions  containing 
more  than  80  per  cent.  (Table  I)  or  83  to  84  per  cent,  of  water 
(Table  II,  No.  9  and  10);  a  maximum  rotation  (-)-)  is  shown 
for  yellow  rays. 

4.  In  Table  II  the  phenomenon  appears  that  in  a  solution 
with  about  92  per  cent,  of  water  there  is  equally  strong  rota- 
tion for  all  colors,  and  that  one  with  q  =  95  shows  a  minimum 
rotation  for  yellow  light,  and  then  increasing  left-hand  rotation 
toward  the  violet  end. 

i  Nasini  and  Gennari :  Ztschr.  phys.  Chem.,  19,  113  (1891). 


ROTATION    DISPERSION    OF   LIQUIDS,    ETC. 


161 


There  is  less  certainty  about  these  observations  however, 
because  in  such  weak  solutions  the  observed  angles  of  rotation 
are  very  small.  Such  anomalies  do  not  appear  in  the  results 
calculated  for  q  =  92  and  95  from  the  interpolation  formulas 
of  Woringer,  but  a  maximum  is  shown  for  the  yellow  rays. 

Boric  acid  does  not  correct  the  irregularities  in  the  dispersion 
of  malic  acid  (Nasini  and  Gennari). 

Equimolecular  Mixture  of  Nicotine  and  Glacial  Acetic  Acid, 
Treated  with  Water, — In  such  combinations,  Gennari1  has 
observed  the  appearance  of  anomalous  dispersion,  but  only 
within  very  narrow  limits  of  concentration.  The  specific 
rotation  of  nicotine  was  found  in  the  following  mixtures  by 
means  of  the  ray-filter  method  (for  yellow,  the  sodium  flame 
however)  at  a  temperature  of  20°  : 


[«Jred                [a]^ 

[«L.        [«]» 

[«1- 

Pure  nicotine          | 
d\°  =  1.0107             j 

-123.37-162.84 

—  209.78  —250.71 

-317.79 

Equimolecular     mixture] 


— 143.54 


acetic  acid. 

J 

Mixtures  of 

the  same 

with  water. 

Orijrinal 
mixture. 

Water  g. 

81.26 

18.74 

—  9.20 

—  12.57 

-1683 

—21.99 

—26.68 

78.87 

21.13 

-4-13 

—5.82       —8.20 

—  10.92 

77-84 

22.16            —1.70 

—2.73      —4.39 

-6.63 

—9-93 

77-45 

22.55               —0.12 

—0.54      —1.48 

—2.80 

—5.00 

76.39 

23.61               —0.78 

-ro.52 



-0.75 

76.30 

23.70               "-I.36 

-0.98 

-fo-74 

—1.40 

76.23 

23.77 

-|  5.90 

+7-44 

-8.85 

-9.87 

76.10 

23.90 

-12.92 

4-16.74 

-20.72 

+24.56 

28.00 

Specific  rotation  of 
nicotine  acetate 

Salt. 

Water. 

53-72 

46.28 

-}  16.44 

-21.36     —25.81 

-29.05           .  .. 

44-3° 

55.70            -14-30 

18.85      -22.83 

-26.57     —31.37 

26.  d8 

73-52                     V2I 

17-35      -21.23 

-23.98 

24.28 

75.72               i  ;.co 

—  1696     —20.41 

-23.50 

25.84 

1  Gennari :  Ztschr.  phys.  Chem.,  19,  130. 
II 


162 


PHYSICAL   LAWS   OF    CIRCULAR    POLARIZATION 


As  immediately  apparent,  pure  nicotine  and  the  mixture  of 
this  with  one  molecule  of  acetic  acid  possesses  a  normal  left- 
hand  rotation,  increasing  with  the  refrangibility  of  the  light. 
As  nicotine  acetate  rotates  to  the  right  it  appears  that  a  part  o 
the  nicotine  in  the  mixture  must  exist  in  the  uncombined 
condition. 

The  peculiarities  in  dispersion  which  appear  when  water  is 
added  to  the  equimolecular  mixture  of  acetic  acid  and  nico- 
tine, can  be  best  seen  from  the  following  diagram.  This  extends 
from  the  red  only  to  light  blue,  as  [a]  for  dark  blue  had  to  be 
omitted  on  account  of  incompleteness  in  the  observations: 


Left-rotation. 
(a)        blue  +-**  red. 

22°20  18  16   14   12   10    8     6     4     2     0     2     4     6 


Right-rotation. 
•  red  *>-*•  blue.  (a] 

8    10  12  14  16  18  20  22  24  26° 


q  =  18,74 

21  13 

2216 

22.55 

2361 

2370 

2377 

23,90 

It  will  be  seen  that: 

1.  In  mixtures  with  18.74  to  22-55  Per  cent,  of  water  there 
is  normal  left-hand  rotation  for  the  different  colors  and  that 
this  decreases,  the  dispersion  also,   with  increasing  amount  of 
water. 

2.  The  solutions  containing  from  23.77  to  23.90  per  cent,  of 
water  possess  right  rotating  power,  which,   with   the  disper- 
sion, increases  in  marked  degree  by  the  slight  increase  in  the 
amount  of  water. 

3.  With  an  amount  of  water  varying  from   23.61  to  23.70 
per  cent.,  the  rotation  and  also  the  dispersion  are  very  small, 
the  first  solution  showing  complete  inactivity  for  green  rays 
and  the  second  for  light  blue  rays.     We  have  here  then  the 
case  of  appearance  of  a  minimum  of  rotation  with   increasing 
refrangibility  of  the  light. 


ROTATION   DISPERSION   OF   LIQUIDS,    ETC. 


163 


Nicotine  acetate  shows  normal  dispersion  in  solutions  con- 
taining 46  to  76  per  cent,  of  water,  as  appears  from  the  above 
table. 

Of  interest  finally  are  the  conditions  of  dispersion  in  solu- 
tions of  nicotine  in  acetone,  ethyl  alcohol  and  propyl  alcohol,  for 
which  Nasini  and  Gennari1  found  the  following  specific  rotations: 


P 

C 

[a]red 

[«]/> 

[•Lr 

M* 

[«]<« 

Acetone  

22  OO 

2O  77 

A  Q1 

6  01 

7   IO 

7  C1 

8  90 

^VJ.  // 

^•Vo 

/•*** 

/•OO 

Ethyl  alcohol  

21.40 

19.09 

-5-73 

-7.09 

—  9.01 

-9.71 

-  10.32 

Propyl  alcohol  •  •  • 

21.15 

19.06 

-3-30 

-3-62 

-  3-92* 

-3.88 

-  3-07 

The  rotation  and  dispersion  of  nicotine  in  these  solutions 
are  seen  to  be  very  much  decreased.  With  the  propyl  alcohol 
there  is  even  anomalous  dispersion  as  the  green  ray  appears  to 
have  suffered  the  greatest  deviation. 

In  regard  to  the  explanation  of  anomalous  rotation  disper- 
sion, Biot2  has  shown  at  length  that  the  phenomenon  must 
appear  when  the  ray  of  light  passes  two  liquid  layers  which 
rotate  the  plane  of  polarization  in  opposite  directions,  and 
which  at  the  same  time  possess  different  dispersive  powers. 
He  employed  in  experiments  left-rotating  turpentine  and  a 
solution  of  right-rotating  camphor  in  acetic  acid,  which  were 
contained  in  tubes  placed  one  behind  the  other,  and  showed 
by  calculation  howr  the  length  of  the  column  of  the  camphor 
solution  and  its  concentration  must  be  changed  to  reach  a 
maximum  or  minimum  of  rotation  for  a  given  ray.  That  a 
perfect  achromatism,  that  is  equally  strong  rotation  for  all 
rays  is  possible,  has  been  shown  by  investigations  of  Nasini 
and  Gennari.3 

The  same  conditions  naturally  obtain  when  two  oppositely 
rotating  liquids  are  mixed  in  different  proportions.  Thus, 
v.  Wyss4  was  able  to  show  a  maximum  of  rotation  for  yellow7 
light  of  wTave-length  565  up  in  mixtures  of  right  and  left 
turpentine  oil.  Further,  Genuari5  found  that  if  to  a  solution 

1  Nasini  and  Gennari:  Ztschr.  phys.  chem.,  19,  117. 

2  Biot:  Ann.  chim.  phys..  [3],  36,  405  (1852). 
'  Xasini  and  Gennari:  loc.  cit.,  p.  121. 

4  v.  Wyss :  Wied.  Ann.,  33,  554  (1888). 

5  Ztschr.  phys.  Chem.,  19,  134  (1896). 


164  PHYSICAL   LAWS   OF   CIRCULAR  POLARIZATION 

of  right-rotating  nicotine  sulphate,  left-rotating  nicotine 
be  added  gradually,  in  small  portions,  the  rotation  for  the 
different  colors  grows  less  and  less,  and  that  finally  the 
left  rotation  of  the  nicotine  appears  in  increasing  degree 
for  all  rays.  There  is  here  the  same  condition  as  with  the 
above-mentioned  mixtures  of  nicotine,  acetic  acid  and  water, 
and  the  phenomena  which  these  exhibit  may  be  explained  by 
assuming  that  the  different  solutions  contain  at  the  same  time 
right-rotating  nicotine  acetate  and  left-rotating  free  nicotine  in 
variable  proportions. 

But  on  what  the  anomalous  dispersion  of  the  aqueous  solu- 
tions of  malic  acid  and  tartaric  acid  depends,  has  not  yet  been 
definitely  shown.  An  attempt  at  an  explanation  will  be 
referred  to  later  in  §63. 

Finally,  a  special  class  of  anomalous  dispersion  phenomena 
must  be  mentioned,  which  appear  when  the  active  solutions 
are  colored.  If  white  light  is  sent  through  these,  absorption 
of  some  of  the  rays  follows,  and  the  rotation  of  those  remaining 
does  not  then  change  regularly  with  the  .wave-lengths.  Cotton1 
has  investigated  such  conditions  in  solutions  of  copper  tartrate 
and  chromium  tartrate  in  potash. 

i  Cotton  :  Compt.  rend.,  120,  989,  1044  ;  Ann.  chim.  phys.,  [7],  8,  347  (1896). 


PART  THIRD 


Numerical  Values  for  the  Rotating 
Power.     Specific  Rotation 


47.  In  the  measurement  of  the  optical  activity  of  liquids  and 
dissolved  bodies,  Biot1  introduced  in  1835  the  conception  of 
specific  rotation ,  indicating  by  this  term,  the  angle  of  rotation 
\_oi\  ,  which  a  liquid  would  show  if  it  contained  in  a  volume  of  I 
cubic  centimeter,  i  gram  of  active  substance,  and  should  act  on 
the  polarized  ray  through  a  column  i  decimeter  in  length. 

As  already  explained  in  the  introduction,  §2,  the  specific 
rotation  of  bodies,  in  themselves  liquids,  is  expressed  by  the 
formula 

W  M=777 

in  which 

a  =  the  angle  of  rotation  measured  for  a  ray  of  definite 

wave-length, 

/  =  the  length  of  the  observation  tube  in  decimeters, 
d  =  the  specific  gravity  of  the  liquid,  referred  to  water  at 

4°  as  standard. 

In  the  measurement  of  these  three  quantities,  the  tem- 
perature must  always  be  considered,  and  should  be  kept  the 
same  for  all.  As  normal  temperature,  20°  C.  is  usually  taken. 
The  specific  rotation  of  an  active  liquid  for  a  given  light  and 
temperature,  for  example,  [«]£,  expresses  a  characteristic  con- 
stant for  this  substance. 

For  solid  active  substances  which  are  brought  into  solution 
by  aid  of  an  inactive  solvent,  the  specific  rotation  may  be 
derived  in  two  ways,  on  the  assumption  that  a  is  proportional 
to  the  concentration  : 

i.  With  determination  of  the  concentration,   c,  by  which  is 

1  Biot :  M£m.  de  1'Acad.,  13,  116  (1835).     Ann.  chim.  phys.,  [3],  10,  5. 


1  66  SPECIFIC   ROTATION 

understood  the  number  of  grams  of  active  substance  dissolved 
to  make  100  cc.  of  solution,  we  have  the  formula  : 


2.  With  the  determination  of  the  percentage  strength,  p,  of 
the  solution,  by  which  is  understood  the  number  of  grams  of 
active  substance  in  100  grams  of  the  solution,  and  further  of 
the  specific  gravity,  d,  of  the  solution.  We  have  then  the 
formula  : 

..        a  .  ioo 


in  which  p  d  =  c, 

In  many  cases,  especially  where  we  are  concerned  with  single 
values  for  the  specific  rotation,  the  experimentally  simpler 
determination  by  formula  (II)  is  sufficient.  A  solution  is 
made  in  a  flask  holding  ioo  true  cc.  at  20°,  and  this  is  polar- 
ized at  the  same  temperature.  But  if  it  is  desired  to  follow 
changes  in  the  specific  rotation  corresponding  to  changes  in 
the  composition  of  the  solution,  it  is  necessary  to  prepare  the 
latter  by  weighing  the  active  substance  and  the  solvent,  as 
the  percentage  amounts  of  both  must  be  known.  It  then 
remains  to  find  the  specific  gravity  of  the  solution  at  20° 
referred  to  water  at  4°,  determine  the  angle  tf,  and  calculate 
according  to  formula  (III). 

The  details  of  practical  methods  are  given  in  Part  IV. 

As  experience  has  shown  the  specific  rotation  calculated 
from  solutions  is  seldom  a  constant  number  ;  with  most  sub- 
stances the  value  changes  through  several  influences  in  a  more 
or  less  marked  degree,  being  dependent  on: 

1.  The  concentration  of  the  solution. 

2.  The  nature  of  the  solvent. 

3.  The  temperature. 

A  detailed  discussion  of  these  relations  will  be  given  in  the 
following  chapters. 

I.  CONSTANT  SPECIFIC  ROTATION  OF  DISSOLVED 
SUBSTANCES 

48.  Cane-Sugar  was  the  first  substance  whose  specific  rotation 
was  determined  by  Biot  in  1835  and  he  found  that  for  a  con- 


CONSTANT    SPECIFIC    ROTATION  167 

stant  length  of  the  observation  tube  the  angle  of  rotation  was 
proportional  to  the  amount  of  sugar  in  solution;  in  other 
words,  the  same  value  resulted  for  [»]  whatever  concentration 
of  the  solution  was  employed.  The  same  was  found  for  mix- 
tures of  turpentine  and  ether.  Biot,  assuming  from  such 
results,  that  the  amount  of  rotation  is  simply  proportional 
to  the  number  of  active  molecules  passed  by  the  light  in  going 
through  the  solution,  reached  the  following  law: 

' '  When  an  active  substance  is  dissolved  in  an  inactive  sol- 
vent, which  produces  no  chemical  change,  the  angle  of  rota- 
tion observed  is  proportional  to  the  amount  by  weight  of  the 
active  substance  in  the  unit  volume  of  solution,  and  the  specific 
rotation  is  therefore  a  constant  quantity." 

According  to  our  present  knowledge,  however,  perfect  con- 
stancy in  the  values  for  [a]  are  shown  by  but  few  substances. 
Even  with  cane-sugar  later  more  exact  investigations  have 
shown  that  with  decreasing  concentration  of  the  aqueous  solu- 
tion the  specific  rotation  increases  slightly,  it  being  in  fact 
found  that  by  changing  the  percentage  strength  from  65  to  2 
per  cent,  of  sugar,  the  value  [a]D  increases  uniformly  from 
65.62°  to  66.80°,  that  is  about  1.8  per  cent.  (See  §  52.)  On 
the  other  hand  in  certain  cases  even  w?ith  great  variations  in 
the  concentration  no  such  regular  change  in  the  rotation  could 
be  found,  for  example: 

Milk-Sugar  which  was  investigated  in  32  aqueous  solutions 
varying  in  strength  from/  =  2.35  to  p  =  36  per  cent.,  gave 
for  the  specific  rotation  numbers  which  varied  irregularly 
between  the  limits  [<*]£  =  51.94°  and  53.18°.  The  mean  of 
all  determinations  was  [<*]"= :  +  52.53°  for  C12H22OU.H2O 
(Schmoger).1 

Rhamnose  shows  between  the  limits  c  =  3  to  30  the  constant 
specific  rotation  [>]£  =  =  +  8.50°  for  C6H12O5.H2O  (Schnelle 
and  Tollens).2 

Parasantonide  in  Chloroform. — Of  this  very  strongly  rotating 
substance  13  solutions,  varying  in  strength  from/  =  0.14  to 
48  per  cent.,  gave  rotations  between  [or]3  = :  +  887.9°  and 

1  Schmoger:  Ber.  d.  chem.  Ges.,  13,  1922. 

-  Schnelle  and  Tollens:  Ann.  Chem.  (I^iebig),  271,  64. 


1 68  SPECIFIC    ROTATION 

896.5°.  The  mean  of  all  observations  was  [«]2£  =  -f-  890.9° 
which  differs  from  the  extreme  values  by  only  0.5  per  cent. 
The  rotation  is  constant  for  other  light  rays  than  D.  The 
temperature  likewise  did  not  seem  to  exert  any  appreciable 
influence.  In  solutions  of  the  body  in  alcohol,  however,  for 
the  slight  change  in  concentration  from^>  =  0.26  top  =  8.5 
a  change  from  [or]3  =  =  -f  880  to  [>]£'-  -f-  833.9  followed 
(Nasini).1 

Santonide,  dissolved  in  chloroform,  for  all  concentrations 
between  c  =  3  and  30  and  for  all  kinds  of  light  shows  a  con- 
stant specific  rotation.  For  example,  for  yellow,  [#]/>  —  + 
754  (Nasini).2 

Nicotine,  which  possesses  the  specific  rotation  [a]£  =  --  164° 
dissolved  in  benzene  gave  the  following  numbers  : 

Nicotine.  [a]fc°  Nicotine.  [a]K 

p  =  84.36         -  164.29°  p  =  19.00  -  163.95° 

48.02          —  164.14  16.36  —  163.88 

25.47          -  164.10  8.52  -  163.67 

Mean  [a]™  =  -  164.00°. 

There  is  therefore  here  but  a  very  small  change  in  the  specific 
rotation,  amounting  to  only  0.2  percent.  (Hein).3 

In  like  manner  the  specific  rotation  of  nicotine  remains 
almost  unchanged  when  it  is  dissolved  in  ether  or  acetone, 
while  with  aniline  and  toluidine  there  is  a  slight  decrease,  to 
about  [<*]/>  =  -  156.5  (Hein).  The  decrease  in  ethyl  or 
propyl  alcohol  is  somewhat  more,  while  with  water  it  is  very 
marked.  (See  §  52.) 

Cocaine,  dissolved  in  chloroform,  shows  for  solutions  vary- 
ing from  p=io  to  25,  specific  rotations  which  are  always 
between  [>]£  =  -  16.28°  and  —  16.36°  (Antrick).4 

With  several  other  substances,  for  example,  d-camphor  dis- 
solved in.  almond  oil  or  olive  oil  (Aignan),5  and  l-a-camphol 
dissolved  in  alcohols,  acetone,  acetic  ether  or  hydrocarbons 
(Haller)6  constancy  in  the  specific  rotation  was  found,  but  the 

Nasini:  Her.  d.  chem.  Ges.,  14,  1512. 
Nasini:  Accad.  d.  Lincei,  [3],  13  (1882). 
Hein:  Inaug.  Diss..  Berlin  (1896). 
Antrick  :  Ber.  d.  chem.  Ges.,  ao,  321. 
Aignan  :  See  next  paragraph. 
Haller  :  Compt.  rend.,  112,  143. 


VARIABLE   SPECIFIC   ROTATION  169 

experiments   covered   but   small   variations   in  concentration. 
As  is  apparent,  therefore,  the  Biot  law  given  above  possesses 
but  a  limited  applicability. 

II.    VARIABLE    SPECIFIC     ROTATION     OF     DISSOLVED 
SUBSTANCES 

A.  Dependence  of  the  Specific  Rotation  on  the  Concentration  of  the 

Solutions 

49.  In  the  investigation  of  aqueous  solutions  of  tartaric  acid, 
Biot1  found  in  1838,  that  the  specific  rotation  of  this  sub- 
stance was  the  larger,  the  more  dilute  the  solution  employed. 
This  case  was  considered  a  long  time  as  an  exception,  until  in 
1852,  with  the  aid  of  better  polarization  apparatus,  Biot2 
recognized  that  the  phenomenon  appears  with  other  substances 
also.  Thus,  with  increasing  dilution  of  its  solutions  in  alcohol 
or  acetic  acid  camphor  showed  a  decrease  in  specific  rotation, 
turpentine  on  the  contrary,  by  increasing  additions  of  alcohol 
or  olive  oil  an  increase,  and  finally,  even  with  sugar,  a  slight 
increase  was  observed  with  an  increase  in  the  amount  of  water. 
Besides  this,  the  influence  of  the  solvent  was  brought  to  light, 
as  in  the  case  of  camphor  different  values  for  [«]  were 
obtained  by  dissolving  it  in  alcohol  or  in  the  same  amount  of 
acetic  acid.  Biot  then  noted  clearly  the  fact,  that  in  general 
the  values  of  specific  rotations  calculated  from  solutions  are 
more  or  less  variable  numbers,  and  that  consequently  the 
molecules  of  the  active  substances  seem  to  suffer  some  altera- 
tion by  the  presence  of  the  inactive  solvent  particles.3 

For  a  long  time,  however,  this  widening  of  our  knowledge 
of  specific  rotation  remained  largely  unnoticed.  The  fact  that 
in  solutions  of  cane-sugar,  the  angle  of  rotation  is  almost 
exactly  proportional  to  the  concentration,  and  that  accordingly 
from  the  observed  angle  of  rotation,  the  amount  of  sugar  can 
be  calculated,  led  to  the  construction  of  the  optical  saccharim- 
eters  which  soon  became  extensively  used,  and  were  also 

1  Biot  :  M6m.  de  1'Acad.,  15,  93  ;  Ann.  chim.  phys.,  [3],  10,  385. 

2  Biot  :  Ann.  chim.  phys.,  [3],  36,  257. 

3  Several  French  investigators  as  Aignan  (Pouvoir  rotat.  spec.  d.  corps  act.  dissous. 
These,  Paris,  1893,  and  Freundler,    (Ann.  chim.  phys.,   [7],  4,  244,  (1895))  refer  to  the 
constancy  of  [a]  as  Biot's  law  and  state  the  case  as  if  I  (I,andolt:  Ann.  Chem.  (L,iebig), 
189,  (1877))  had  first  shown  its  inaccuracy,  whereas,  this  had  long  since  been  shown 
by  Biot  himself. 


170  SPECIFIC    ROTATION 

employed  in  the  investigation  of  other  substances.  In  spite 
of  the  fact  that  Biot1  in  1860  had  published  an  extended  paper, 
which  contained  a  resume  of  all  his  work  in  this  field,  and 
again  called  attention  to  the  correct  relations,  the  opinion  was 
still  in  the  main  held  that  active  substances  in  general  behave 
as  does  cane-sugar  ;  it  was  therefore  considered  sufficient  in 
the  optical  examination  of  a  substance  to  determine  the 
rotation  for  a  single  solution  and  then,  from  this,  by  aid  of 
formula  II  or  III,  to  calculate  the  specific  rotation  and  con- 
sider this  as  constant.  In  this  way,  a  great  many  specific 
rotations  have  been  determined,  which,  generally  with  no 
mention  of  the  concentration  or  solvent  employed,  have 
slipped  into  the  physical  and  chemical  handbooks  and  have 
been  retained  for  a  long  time. 

In  1873  Oudemans"  independently  found  that  the  specific 
rotation  can  assume  very  different  values  when  different 
inactive  liquids  are  used  as  solvents.  Hesse3  published  in  1875 
a  large  number  of  determinations  of  rotations,  of  over  fifty 
active  substances,  and  in  solutions  of  different  concentrations. 
Even  with  only  small  variations  in  the  latter  (between  i  and 
10  grams  in  100  cc. )  nearly  all  bodies  exhibit  marked  differences 
in  specific  rotation,  and  in  most  cases  a  decrease  in  this  with 
increase  in  concentration.  Still  greater  differences,  amounting 
often  to  over  50  per  cent.,  were  found  by  varying  the,  liquids 
employed  as  solvents.  The  numerous  investigations  which 
have  been  carried  out  in  the  last  twenty  years  on  the  rotation 
of  new  organic  substances  have  led  to  the  same  results. 

50.  The  Determination  of  the  True  Specific  Rotation  of  Dissolved 
Substances,  According  to  Biot. — Only  such  value  can  be  given  to 
the  specific  rotations  calculated  from  a  single  solution  as 
attaches  to  a  constant  obtained  under  special  conditions.  But 
Biot*  showed  long  ago  in  his  investigations  on  the  rotation  of 
tartaric  acid  how  a  definite  meaning  may  be  given  to  these 
variable  numbers  and  this  is  explained  in  the  following  con- 
siderations: 

1  Biot:  Ann.  chim.  phys.,  [3],  59,  206. 

2  Oudemans:  Pogg.  Ann.,  148,  337  :  Ann.  Chem.  (Liebig),  166,  65. 
8  Hesse:  Ann.  Chem.  (Liebig),  176,  89,  189. 

4  Biot:  M£m.  de  PAcad.,  15,  205  (1838);  16,  254  (1838);  Ann.  chim.  phys.  [3],  10, 
385  (1844);  38,  215  (1850);  36,  257  (1852);  59,  219  (1860). 


TRUE   SPECIFIC    ROTATION  171 

For  liquid  active  substances  the  specific  rotation  may  be 
directly  determined,  and  for  a  given  temperature  this  is  a  con- 
stant. If  now  such  a  body,  for  example  turpentine,  be 
mixed  in  different  proportions  with  an  indifferent  liquid,  such 
as  alcohol,  and  then  from  the  percentage  amount,  the  specific 
gravity  and  observed  rotation,  the  specific  rotations  be  calcu- 
lated, values  result  which  differ  more  or  less  widely  from  that 
found  for -the  pure  substance.  The  original  rotation  of  the 
body  undergoes  then  a  change  by  reason  of  the  presence  of 
the  inactive  molecules,  most  active  substances  showing  an 
increase  in  rotation;  a  few,  however,  a  decrease  in  specific  ro- 
tation by  increase  in  the  amount  of  the  solvent.1 

If  the  active  body  is  solid  it  can  be  investigated  only  in  solu- 
tion, and,  according  to  the  constitution  of  the  latter,  different 
numbers  for  the  specific  rotation  are  obtained  which  do  not 
represent  the  real  specific  rotation  of  the  pure  substance  but 
values  modified  by  the  presence  of  the  inactive  solvent  and 
differing  from  the  first  to  an  extent  which  is  quite  unknown. 

If  a  pure  homogeneous  liquid  is  employed  as  solvent  so  that 
indifferent  molecules  of  one  and  the  same  kind  only  affect  the 
molecules  of  the  active  body,  changes  in  the  specific  rotation 
may  be  followed  most  readily  by  graphic  representation  by 
taking  the  percentage  amounts  of  inactive  solvent  (^)  as  ab- 
scissas in  a  coordinate  system,  while  the  corresponding  values 
for  [a~\  are  taken  as  ordinates.  An  increase  or  decrease  in  the 
specific  rotation  is  often  shown  then  as  a  straight  line  which 
inclines  in  proportion  to  changes  in  q  and  which  may  be  repre- 
sented by  the  general  formula 

(I)  [>]=A  +  B?, 

the  constants  in  which,  A  and  B,  may  be  calculated  from  the 
experiments.  In  other  cases,  on  the  contrary,  the  line 
obtained  is  not  straight,  but  is  a  curve,  ordinarily  a  part  of  a 
parabola  or  hyperbola,  in  which  case  the  dependence  of  the 

1  This  could  be  seen  by  aid  of  a  polarization  apparatus  placed  vertically,  the  obser- 
vation tube  being  left  open  above.  I,et  turpentine  oil,  for  example,  be  poured  into 
the  tube  and  say  i  cm.  in  height,  and  the  rotation  then  observed.  Now  by  adding 
increased  amounts  of  alcohol,  and  observing,  greater  and  greater  rotations  will  be 
found.  The  number  of  active  molecules  is  the  same  throughout,  but  they  are  distrib- 
uted through  a  lengthened  column.  By  employing  nicotine  and  diluting  gradually 
with  water  a  constantly  decreasing  rotation  would  be  found. 


172  SPECIFIC   ROTATION 

specific  rotation  on  q  is  shown  by  an  expression  of  the  form 
(II)          [a]=.4 


or  by  some  other  equation  with  several  constants. 

In  these  formulas,  A  represents  the  specific  rotation  of  the 
pure  substance,  and  the  values  for  B,  formula  (I),  and  for  B 
and  C,  formula  (II) ,  represent  the  increase  or  decrease  which  A 
suffers  by  the  presence  of  i  per  cent,  of  inactive  solvent. 

If  q  =  o  we  have  the  specific  rotation  of  the  pure  substance ; 
if,  on  the  other  hand,  in  equations  I  and  II  we  put  q  =  100, 
there  results  for  [«]  a  value  which  must  be  looked  upon  as 
the  specific  rotation  of  the  body  in  solution  of  infinite  dilution. 
If  we  assume  that  in  the  case^— 100,  the  active  body  has 
entirely  disappeared,  and  the  liquid  consists  of  the  inactive 
solvent  only,  the  rotation  then  must  become  o.  This,  accord- 
ing to  Biot,2  may  also  be  derived  from  the  above  expressions, 

by  putting  them  equal  to  the  equation  [or]  —       ' '         ,  which 

represents  the  specific  rotation  as  calculated  directly  from  the 
observed  rotation  a.     If  in  the  last  equation,  in  place  of  p, 

1  The  three  constants,  A,  Band  Cof  the  formula  [a]  =  A  +  £  may  be  found  ac- 
cording to  Biot  (Ann.  chim  phys.,  [3],  n,  96,  §69)  in  the  following  way,  if  for  three 
solutions  with  ft,  q<>  and  q%  per.  cent,  of  inactive  solvent,  the  corresponding  specific 
rotations,  [a]i»  [a]2  and  [o]3  have  been  determined. 

If  we  take 

then  the  values  for  a  and  c  follow  from  these  equations  : 

(Mztfa  —  Mi  ft)  +  (Ma—  Mi)  c  —  (ft  — ft)  «  =  °> 

(Ms  ft— Mi  ft)  +  (Ms—  [*[\)c—  (ft-  ft)  a  =  o, 

and  therefore  *  from  each  of  the  following  equations  : 

(Mi  — «)  (?i  +c)  =  — *, 
(Mi  — «)  (ft  +  c)  =  —  *, 

.  (Ms  — «)  (ft  +  c)  =  —  b, 

Finally  we  have 

Biot  brings  the  equation 

also  into  the  form  : 

[a]=A  +  i  ^qc  q    in  which    ff  =  ~-    and    C  =  -£-. 

Instead  of  q  in  the  above  formulas  we  can  naturally  introduce/  and  write 
M  =**  +S(ioo—p), 
[a]  =A  +  ff  (zoo  —  p)  +  C  (100  — /)2. 
»  Biot :  Ann.  chim.  phys.,  [3],  10,  399,  §  59  ;  59,  224,  §  15. 


TRUE    SPECIFIC  ROTATION  173 

inasmuch    as  p  +  q  =  100,  we  put    the  value  100  —  <?,  and 
take,  for  example,  using  formula  (I), 
a.  ioo 

/.rf(,oo-g)  ==  A  +  Bq> 
there  follows 

«  =  i.d  \A  +  (B  -  —\g  —  —<?  1 . 

L  V  ioo/  a        ioo*    J 

If  in  this  equation  we  place  q  =  ioo,  then  a  =  o  ;  that  is,  the 
rotation  has  disappeared.  If,  on  the  other  hand,  q  =  o  then 
there  results  ot  =  I.d. A;  that  is  the  angle  of  rotation  which  a 
column  of  the  pure  active  substance  /  dm.  long  with  the  specific 

gravity  d  shows.     From  this  —  =  A  results  and  as  at  the  same 

time  —  =  [ar]  it  follows  that   [or]  =  A,  that  is,  the  specific 

rotation  of  the  pure  substance  without  solvent. 

With  active  liquid  bodies  which  may  be  mixed  in  all  pro- 
portions with  the  inactive  solvent,  the  change  in  the  original 
specific  rotation  may  be  followed  by  experiment  to  the  most 
dilute  solutions,  and  consequently  the  whole  curve  from  q  =  o 
to  nearly  q  =  TOO  may  be  constructed.  If  from  a  number  of 
solutions  in  this  case  the  constant  A  be  calculated,  a  value 
must  result  which  agrees  the  more  perfectly  with  the  real 
specific  rotation  of  the  pure  substance,  the  larger  the  portion 
of  the  curve  covered  by  the  observations  and  the  nearer  this 
approaches  the  abscissa  q  =  o,  that  is  the  greater  the  corre- 
sponding concentration. 

If  the  active  substance  is  solid  its  original  specific  rotation 
can  not  be  directly  determined,  and  at  the  same  time,  depend- 
ing on  the  conditions  of  solubility,  only  a  more  or  less  com- 
plete portion  of  the  curve  may  be  established,  beginning  at 
some  distance  from  the  zero-point  of  the  coordinate  system. 
If  the  constants  of  the  formulas  (I)  and  (II)  be  calculated 
from  the  observations  made,  the  values  obtained  can  be  used 
for  interpolation  with  accuracy  only  within  the  limits  of  con- 
centration embraced  by  the  solutions  used  for  the  experiments. 

It  may  be  asked  now,  how  far  one  is  justified  in  such  a  case  in 
looking  upon  the  value  obtained  for  A  as  representing  the 
specific  rotation  of  the  pure  substance.  Th,e  extrapolation 


174  SPECIFIC    ROTATION 

which  is  made  here  is  allowable  when  the  change  in  the 
specific  rotation  is  represented  by  a  straight  line,  that  is  by 
the  formula  [ar]  =  A  +  Bq.  If,  however,  it  is  a  curve,  the  A 
calculated  from  the  formula  [or]  =  A  -f-  B  q  -f-  C<f  (or  some 
other  one)  will  represent  the  true  specific  rotation,  the  less 
accurately,  the  smaller  the  portion  of  the  curve  which  could  be 
obtained.  How  far  this  end  may  be  reached  depends,  there- 
fore, on  the  greater  or  less  solubility  of  the  active  body.  If 
only  dilute  solutions  of  it  may  be  prepared,  and  if  it  appears 
at  the  same  time  that  the  values  for  [#]  do  not  increase  or 
decrease  linearly  with  q,  then  there  is  no  hope  that  the  specific 
rotation  of  the  pure  substance  may  be  reached. 

If  in  formulas  (I)  and  (II)  instead  of  q,  the  amount  of 
active  substance  in  100  parts  of  solution,  that  is,  p,  be  taken, 
then  the  constant  A  represents  the  specific  rotation  in  con- 
dition of  infinite  dilution,  and  the  rotation  of  the  pure  sub- 
stance follows  when/  =  100  is  taken.  But  the  use  of  q  is  to 
be  preferred,  according  to  the  above  explanations. 

In    finding   the  specific  rotation  according  to  the  formula 

[a]  =    — j the  determination  of  the  specific  gravity  of  the 

solution  is  omitted,  and  only  the  concentration,  c,  by  aid  of  a 
flask  of  known  volume,  determined.  If  we  change  then  the 
above  equations  (I)  and  (II)  into  [or]  =  21  -f-  33^ and  $1  -f-  Sfc-j- 
($,c*  and  place  c—  100,  there  results  the  specific  rotation  for  a 
solution  which  contains  in  100  cc.  100  grams  of  active  substance. 
But  this  would  represent  the  pure  substance  only  when  its 
specific  gravity  is  equal  to  unity  ;  but  if  this  is  different,  =  tf , 
which  is  practically  always  the  case,  then  for  the  value  c,  100  d 
must  be  substituted.  This  requirement  can  be  satisfied  but 
rarely,  and  even  then  not  with  certainty,  as  it  assumes  a 
knowledge  of  the  specific  gravity  of  the  active  substance  in  an 
unknown  amorphous  condition  ;  numerical  values,  therefore, 
of  specific  rotations  coupled  only  with  the  concentration, 
without  definite  statements  as  to  the  specific  gravity  and 
percentage  composition  of  the  solutions,  can  not  be  used  to 
calculate  the  true  specific  rotation  of  the  substance  free  from 
solvent. 


REDUCTIOX    FORMULAS  175 

Finally,  with  reference  to  crystallized  bodies,  it  must  be 
understood  that  the  constant  A,  calculated  from  their  solu- 
tions, expresses,  as  a  matter  of  course,  only  the  rotation  which 
is  characteristic  of  the  molecule.  This  value  may  be  very 
different  from  the  specific  rotation  which  belongs  to  the  solid 
crystal,  as  shown  in  §  7,  because  here,  besides  the  molecular 
rotation,  the  crystal  rotation  comes  into  play  also. 

5-1.  Reduction  Formulas. — Alterations  in  specific  rotation  of 
dissolved  bodies  may  be  expressed,  as  explained  above,  as 
functions  of : 

1 .  The  percentage  amount  of  inactive  solvent,  g: 

(I)  M  ==  A  +  Bq  +  Qn 

2.  The  percentage  amount  of  active  substance,  p  : 

(II)  [a]  ==«  +  #  +  #»; 

3.  The  concentration,  c,  or  grams  of  active  substance  in  100 
cc.  of  solution: 

(III)  [a]  ==%  +  8<r+  (Er, 

in  wrhich  case,  however,  the  constant,  21,  has  no  definite  meaning. 

In  many  cases  the  third  constant  in  these  expressions  dis- 
appears. 

For  transformation  of  the  constants  of  the  equations  (I) 
and  (II)  we  take:1 


a  =  A  -f  loo  B  -\-  10,000  C 
b  =  —  B  —  200  C 

c  =  C 


A  =  a  -\-  loo  b  -{-  io,ooor 
B  =  —  b  —  200  c 


=  c. 


Thus  Toilens2  established  the  following  formula  for  cane- 
sugar  in  an  aqueous  solution  which  holds  within  the  limits, 
p  =  3  to  p  =  69  per  cent. , 

[or]  D  =  66.386  -f  0.015035^  —  0.0003986  /, 
from  which  follows  for  q  =  31  to  97  per  cent., 

[«]/>  —  63. 904  +  0.064686?-— 0.00039864*. 

1  The  calculation  of  A  from  equation  (II)  follows  by  taking  in  equation  (I)  q  =  o 
and  in  (II)  p  =  100  and  then  equating  the  two.     On  the  other  hand  a  follows  from 
equation  (I)  when  in  (I)  we  take  q  =  100  and  in  (II)  p  =  o. 
As  P  +  9  =  loo  we  have  further  the  equations: 

A  +  B  (too  —p)  -j-  C  (100  —  p)*-  =  A  +  100  B  +  10,000  C  +  bp  +  cp*, 
a.  +  b  (100  —  9)  -  c  (loo  —  q)-  =  a  +  100  £  +  10,000  c  -f  Bq  +  Q2, 
from  which  the  relations  between  B  and  b,  and  Cand  c  follow. 
•  Toilens  :  Her.  d.  chem.  Ges.,  10,  1410  ;  17,  1757. 


I  76  SPECIFIC    ROTATION 

Landolt1  found  for  camphor  dissolved  in  benzene  within  the 
limits  q  =  37  to  q  =  76  : 

[(*]D  =  55-21  —0.1630?, 
from  which  follows  for  p  =  24  to  63  per  cent., 

[>]/>  =  38-91  +  0.1630  p. 

It   is  sometimes  required  to  change   the  constants   of    the 
equation 

[a]  =  a  +  bp  +  #', 

for  a  substance  with  molecular  weight  J/  so  that  they  will 
apply  for  a  derivative  (hydrate,  salt,  etc.)  with  the  molecular 
weight  MI  .  Then  the  above  formula  becomes  : 

[a]  =  a,  +  b,p  +  c,p\ 
and  the  constants  of  this  are  found  :2 
i.  In  the  case,  M  <  Ml  from 


2.  In  the  case,  M^>  Ml  from 


For  example,  the  following  equation  was  established  by 
Tollens3  for  anhydrous  glucose,  C6H12O6,  M=  180: 

M/?  —  52-5°  +  o.  018796  p  4-  0.00051683  /2. 
From  this  there  may  be  derived  for  the  hydrate,  C6Hj.,O6  -f 
H2O,  Ml  ==  198,  the  following  formula,  taking  into  considera- 
tion that  M  <C  MI  : 

[«]/>  =  47-73  +  o-oi5534  P  +  0.00038830  p\ 

52.  Experimental  Proof  of  Blot's  Formulas.  —  With  what  degree 
of  certainty  the  true  specific  rotation  of  a  substance  may  be 
calculated  from  observations  on  its  solutions  can  be  determined 
by  experiments  on  active  liquid  bodies.  First,  the  specific 
rotation  is  found  directly,  and  then  a  number  of  mixtures  with 
inactive  liquids  are  prepared  and  from  the  observed  rotations 
in  these  the  constants  in  the  formula  [a]  =  A  -f  Bq  or  [or]  = 

1  I^andolt:  Ann.  Chem.  (Uebig),  189,  334. 

-  In  the  introduction,  §2,  the  calculation  is  carried  out  only  for  the  case  M  <  M\. 

3  Tollens:  Ber.  d.  chem.  Ges.,  17,  2238. 


EXPERIMENTAL   PROOF   OF    BIOT  S   FORMULAS 


177 


A  -(-  Bq  -f  Cq'  are  derived.  The  values  obtained  for  A  by 
using  different  solvents  must  all  agree  very  closely  with  the 
observed  value  \_at~] ,  and  it  remains  to  see  how  far  this  agree- 
ment is  diminished  when  only  solutions  of  low  concentration 
are  employed  in  the  calculations,  as  is  the  case  with  bodies  of 
slight  solubility. 

Experiments  of  this  kind  have  been  made  with  right  and 
left  turpentine,  nicotine,  and  ethyl  tartrate  (Landolt).1 

In  the  following  observations,  which  for  purpose  of  illustra- 
tion are  given  in  full,  the  angles  of  rotation  were  found  mostly 
by  aid  of  the  Wild  polaristrobometer  and  as  the  means  of  ten 
single  observations.  The  normal  temperature  of  20°  employed 
was  secured  by  jacketed  tubes;  the  densities  d  are  reduced  to 
water  at  4°  as  standard.2 

/.  Left  Turpentine  Oil. 

The  French  oil  with  boiling-point  160°  to  162°  was  used 
and  the  rotation  found  in  two  tubes  of  different  length  : 


d;° 

I  in  dm 

a21 

M~° 

0.8629      0.9992      -31.91     —37.00 


2.1979 


—  70.20    — 37.02 


Mean.  — 37.01. 


a.  Mixtures  with  Alcohol. 
The  specific  gravity  of  the  alcohol  used  was, 


=  0.7957: 


Mixture     Turpentine  oil. 
No.                     p 

Alcohol.                  J20 
q                       U4 

a  for 
/  =  2.1979  dm. 

MS 

I 

90-05                9-95 

0.8556 

-62.720 

-  37.04° 

II 

69.94 

30.06 

0.8392 

-  48.05 

—  37.25 

III 

49-97 

50.03 

0.8254 

-  34-04 

-  37-55 

IV 

29.97 

70.03 

0.8127 

—  20.29 

-  37-90 

V 

10.01              89.99 

O.SoiI 

-     6.78 

-  38.49 

1  Landolt:  Ann.  Chem.  (Liebig),  189,  311  (1877). 

2  In  the  following  tables  all  the  numbers,  which  in  the  original  paper  were  carried 
out  to  four  places  of  decimals  for/>  and  q,  to  five  places  for  d  and  to  three  places  for  a 
and  [a],  have  been  shortened.     In  consequence  a  recalculation  of  [a]   might  lead  in 
some  instances  to  values  differing  by  one  or  two  units  in  the  last  decimal  from  those 
now  given.     But  this  is  of  no  consequence  for  the  present  purpose. 

12 


178 


SPECIFIC    ROTATION 
b.  Mixtures  with  Benzene 


The  benzene  used  had  a  boiling-point  of  80.4°  and  a  specific 
gravity,  d™  =  0.8803  : 


Mixture 
No. 

Turpentine  oil.       Benzene. 
P                          1 

rf? 

a  for 
/  =  2.  1979  dm 

Ms 

I 

89.92 

10.08 

0.8634 

-63.470 

-37.19° 

II 

77-93 

22.07 

0.8644 

—  55.50 

—  37.49 

III 

65.06 

34.94            0.8656 

-46.79 

-37.80 

IV 

51-05 

48.95 

0.8677 

-37-18 

-38.18 

V 

36.90 

63.10 

0.8705 

—  27.20 

-38.52 

VI 

22.06 

77-94 

0.8738 

-17.21 

—  39-03 

VII 

9.98 

90.02 

0.8771 

—  7-59 

-39-45 

c.  Mixtures  with  Acetic  Acid 

The  acetic  acid  used  had  a   density,    ^f 
sponding  to  99.8  to  99.9  per  cent,  of  real  acid. 


1.0502,   corre- 


Mixture 
No. 

Turpentine  oil. 
P 

Acetic  acid. 
9 

d? 

a  for                  r  _,-i  20 
/=  2.i979dm.  i         L"J^ 

1 

I 

90.16 

9.84 

0.8757 

-64.46° 

-37.15° 

II 

78.07 

21.93 

0.8917 

-57.23 

—  37-41 

III 

64.86 

35-14 

0.9116 

—  49.24 

-37.89 

IV 

50.97 

49.03 

0-9353 

-40.27 

-38.43 

V 

22.96 

77-04 

0.9918 

-19.86 

-39.67 

VI 

9.84 

90.16 

1.0233 

-    8.90 

—  40.22 

As  the  above  observations  show,  the  specific  rotation  of  the 
turpentine  increases  in  all  cases  with  increase  in  the  amount 
of  inactive  solvent  q,  and  in  the  curves  shown  in  the  graphic 
illustration  (Fig.  16)  that  for  acetic  acid  ascends  the  most 
rapidly,  that  for  benzene  less,  and  that  for  alcohol  the  least. 
The  curvature  of  these  is  not  great,  but  they  differ  too  much 
from  a  straight  line  to  permit  the  application  of  the  formula 
[a]  —  A  -f-  Bq.  If  the  constant  A  is  determined  from  two 
mixtures,  values  are  found  which  are  always  smaller  than  the 
specific  rotation  of  the  pure  turpentine  oil  (37.01),  and  which 
depart  the  more  widely  from  this,  the  more  dilute  the  solu- 
tions are  that  are  used  in  the  observations.  This  is  shown, 
for  example,  by  the  following  figures : 


EXPERIMENTAL   PROOF   OF    BIOT'S   FORMULAS  179 


Fig.   16. 

From  the  mixtures  There  results  Deviation  from       Extrapolation, 

with  alcohol.  A=  37  01.  Percent. 

I  and  II  36.93  —  0.08  10 

II  "  III  36.79  —0.22  30 

III  "    IV  36.66  -0.35  50 

IV  "      V  35.87  -  1.14  70 

If,  on  the  other  hand,  the  formula  \_a~\  =  A  -\-Bq-\-  Cq1 ', 
be  used  and  the  constants  be  calculated  from  solutions  with 
the  smallest,  a  mean,  and  the  largest  value  for  q,  there  results 
for  A  a  number  which  is  very  near  the  specific  rotation  of  the 
pure  turpentine  oil,  and  further,  the  formula  agrees  in  a  very 
satisfactory  manner  with  the  whole  determined  curve  from 
q  =  10  to  90. 

There  follow  from  the  mixtures  with 

a.  Alcohol,  calculated  from  solutions  I,  III,  V, 

M/>  =  36-97  4-  0.004816  q  -f  0.0001331  <f. 

b.  Benzene,  calculated  from  solutions  I,  IV,  VII, 

[<*]D  =  36.97  -I-  0.021531  q  +  0.0000667  <f- 


i8o 


SPECIFIC    ROTATION 


c.  Acetic  Acid,  calculated  from  solutions  I,  IV,  VI, 

Mz?  =  36.89  -f-  0.024553  q  -j-  0.0001369  <f. 
These  formulas  give  the  following  interpolation  values: 


MWWUM                amMm+w  c 

in                         No. 

g 

Observed. 

Calculated. 

Cal.—  Obs. 

Alcohol.-..    {        £ 

30.06 
70.03 

37-25° 
37-90 

37-24° 
37-96 

—  0.01° 
+  0.06 

II 

22.07 

37-49 

37-48 

—  O.OI 

Benzene  .... 

III 
V 

34-94 
63.10 

37.80 
38.52 

37.80 
38-59 

0.00 

-f  0.07 

VI 

77.04 

39-03 

39-03 

o.oo 

n 

21.93 

3741 

37-50 

4-  0.09 

Acetic  acid.   \        III 

35-14 

37.89 

37-93 

-f  0.04 

V 

77-04 

39  -67 

39.60 

—  0.07 

If  we  employ  only  the  dilute  solutions  in  calculating  the 
constant  A,  by  the  three-term  formulas,  deviations  of  the 
following  kind  are  found: 


From  the  mixtures                                  There  results 

Deviation 

Extrapolation 

with 

A  = 

from  37.01 

Per  cent. 

Alcohol  ...    < 

II,  IV,  V 

37.20° 

+  0.19° 

30 

III,  IV,  V 

35.13 

-  1.88 

50 

Benzene  ...     < 

III,  V,  VI 

37-26 

+  0.25 

35 

V,  VI,  VII 

35-42 

-  1-59 

63 

Acetic  acid.  j 

II,  IV,  VI 
IV,  V,  VI 

36.65 
36.00 

—  0.36 

-   1.  01 

22 

49 

The  deviations  from  the  true  value  amount  then  to  i  °  to  2  ° 
as  soon  as  the  mixtures  contain  more  than  about  50  per  cent, 
of  inactive  liquid. 

II.  Right  Turpentine  Oil. 

The  American  oil  used  showed  at  a  temperature  of  2 1  °  the 
following  densities  and  rotations,  the  last  being  found  by  two 
different  polariscopes: 


0.9108 


Apparatus 

I 
II 


2.1990  dm 
2.1990   " 


<*D 

+  28.35° 
+  28.315 


[«]3 
4- 14.16° 

f  14.14 


Mean,    14.15 


Mixtures  with  Alcohol. 
The  following  mixtures  were  made  : 


EXPERIMENTAL   PROOF    OF    BIOT'S    FORMULAS  l8l 


Mixture 

Turpentine  oil. 

Alcohol. 

/t* 

a  for                    r~lw 

No. 

P 

q 

a4 

/  =  2.199  dm. 

L"J^ 

I 

73-09 

26.91 

0.8765 

4-  20.42° 

+  14-50° 

II 

47-51                  52.49 

0.8464 

+  13-08 

+  14.79 

III 

22.24 

77.76 

0.8186 

-f     6.04 

+  I5.io 

Also  here  with  increasing  dilution,  a  slight  increase  in  the 
specific  rotation  follows,  and  the  graphic  illustration  (Fig.  17) 
shows  that  the  three  points  lie  almost  exactly  in  a  straight 


Ltaoad  in  Alkcfcol 


Alkdbc 


Fig.  17. 


line.     The  simple  formula   [«]  =  A  -f  Bq  can    therefore  be 
applied,  for  the  constants  in  which  we  have  : 


From    I  and    II 

"      II    "     III 

I    "     III 


A  =  14.19 

14.15 
14.18 


B  =  +  0.01142 
0.01215 
0.01178 


The  values  found  for  A  agree,  accordingly,  very  closely  with 
those  found  by  direct  observation  of  the  turpentine  oil  (in 
the  mean  14.15°). 

The  mean  of  the  above  values  for  A  and  B  gives  this 
formula  : 

[_a]%=  14.17  -f  0.01178?. 

III.  Nicotine  (Left- Rotating}. 

A  preparation  secured  by  distilling  the  commercial  product 
in  an  atmosphere  of  hydrogen  was  tested  as  to  purity,  and  was 
found  to  have  a  boiling-point  of  246.6°-246.8°  at  745  mm. 


182 


SPECIFIC   ROTATION 


The  rotation,   as  well  as  that  of  the  mixtures  given  later,  was 
determined  by  means  of  the  Wild  polaristrobometer,  and  was  : 


i. oiio  o.9992dm  —163.20°  —161.55° 

a.  Mixtures  with  Alcohol 
The  alcohol  used  had  a  specific  gravity,  d™  =  0.7957. 


Mixture 
No. 

Nicotine. 
P 

Alcohol. 

q 

d? 

a  for 
/  =  0.9992 

Ms 

I 

90.09 

9.91 

0.9884 

-  141.16° 

-  158.65° 

II 

74-93 

25.07 

0.9536 

—  110.62 

-  154-9* 

III 

59-93 

40.07 

0.9200 

-    83.63 

-  151.78 

IV 

45.08 

54.92 

0.8875 

-    59-49 

-  148.81 

V 

30.03 

69.97 

0.8554 

-    37.32 

-  145.42 

VI 

14.96 

85.04 

0.8251 

—    17-46 

—  141.60 

As  shown,  the  specific  rotation  of  the  nicotine  decreases  as 
the  dilution  with  alcohol  increases.  The  graphic  construction 
(Fig.  1 8)  leads  to  a  straight  line  with  slight  variations  to  either 
side,  and,  corresponding  with  this,  we  obtain  for  the  constants 
of  the  formula  [a]  =  A  -f-  Bq,  almost  the  same  values  what- 
ever mixtures  are  made  the  bases  of  the  calculation  : 


From 
mixtures 

There  results 
A  = 

Deviation 
from  161.55. 

Extrapolation. 
Per  cent. 

B  = 

I  and  III 
II     "    IV 

160.90° 
160.06 

-  0.65° 
1.49 

10 
25 

—  0.2281 
—  0.2049 

III     "      V 

160.31 

-  1.24 

40                      —  0.2127 

IV     "     VI 

161.96 

+  0.41 

55                  -  0.2393 

I     "     VI 

160.90 

—  0.65 

10                  —  0.2269 

We  find  therefore,  from  dilute  solutions  also,  results  for  A, 
which,  in  view  of  the  strong  rotation,  agree  very  well  with  the 
value  found  for  [ar]  (—  -161.55)  from  the  pure  nicotine. 
From  the  means  of  A  and  B  we  obtain  the  formula 

{.<*]%  =  160.83  —  0.2224  q, 
which  leads  to  the  following  interpolation  results  : 


EXPERIMENTAL   PROOF   OF   BIOT'S   FORMULAS 


183 


Mixture 
No. 

1 

w 

Observed. 

l«] 

Calculated. 

Cal.—  Obs. 

I 

9.91 

158-65° 

158-63° 

—  0.02 

II 

25.07 

154.92 

155.26 

+  0.34 

III 

40.07 

151.78 

151.92 

-f  0.14 

IV 

54.92 

148.81 

148.62 

-0.19 

V 

69.97 

145.42 

I45.27 

-0.15 

VI 

85.04 

141.60 

141.92 

+  0.32 

b.  Mixtures  with  Water 


Mixture 
No. 

Nicotine. 
P 

Water. 
Q 

d^ 

/in  dm. 

0$ 

Ms 

I 

89.92 

I0.o8 

.0267 

0.9992 

-  I23.470 

-  133.85° 

II 

78.39 

21.  6l 

.0353 

0.9992 

—    88.82 

—  109.53 

III 

65.90 

34.10 

.0401 

0.9992 

-    64.54 

-  94.24 

IV 

53-48 

46.52 

.0365 

0.9992 

-    47-95 

-  86.58 

V 

34-29 

65.71 

.0228 

0.4982 

-     I4.IT 

—  80.78 

VI 

17-68 

82.32 

.0116 

0.4982 

6.855 

-  76.94 

VII 

16.34 

83.66 

.0096 

0.4982 

6.317 

-  76.88 

VIII 

8.97 

91.03 

1.0047 

0.9992 

6.804 

-  75.53 

From  the  table  it  appears  that  the  specific  rotation  of  the 
nicotine  suffers  at  first  a  very  sharp  decrease  with  increase  in 
the  amount  of  water  added,  which  later  becomes  gradually 
less.  The  strongly  bowed  curve  (Fig.  18)  is  a  limb  of  a 
hyperbola  and  it  is  not  possible  by  use  of  the  formula  [ar]  = 
A  -\-  Bq  -f-  C<f,  even  with  addition  of  a  fourth  or  fifth  member, 
to  reach  a  satisfactory  agreement  with  the  observations.  The 
specific  rotation  of  the  pure  nicotine  may  be  found,  even  ap- 
proximately, only  by  calculation  from  the  numbers  obtained  by 
observations  on  the  strongest  solutions.  There  results,  for 
example : 


From  mixtures 


i,  n,  in. 
163.17 


I,  IV,  VII. 

153.00 


IV,  V,  VIII. 

141.16 


If  it  is  desired  to  express  the  whole  curve,  an  equation  of 
some  other  form  must  be  employed,  as,  for  example,  the 
following  which  contains  five  constants  : 

[a]  =115.019—  i. 70607^  +  V  2140.8—  108.867?+ 2. 5572^. 

1  The  specific  gravity  of  the  mixtures  increases  at  first  with  the  increase  in  the 
water,  reaches  a  maximum  with  mixture  III,  and  then  decreases. 


1 84 


SPECIFIC    ROTATIOX 


Fig.  iS. 


Mixture 
No. 

1 

[«) 

Observed. 

M 
Calculated 

Cal.-Obs. 

I 

10.08 

'33.850 

I33.920 

-|-  0.07 

II 

21.  61          |         109.5.5 

10949 

—  0.04 

III 

34-  'o 

94-24 

94.28 

H  0.04 

IV 

46.52 

86.58 

86.74 

f  0.16 

V 

65.7« 

80.78 

80.56 

—  0.22 

VI 
VII 

82.31 
83.66 

76.94 
76.88 

77.08 
76.84 

-f  0.14 
—  0.04 

VIII 

91.03 

75-53 

75.56 

-fO.03 

EXPERIMENTAL    PROOF   OF    BIOT'S    FORMULAS 


185 


For  pure  nicotine  (^  — o)  the  above  formula  gives 
[«]  =  161.29°,  instead  of  the  observed  161.55°. 

For  q  =  100  [or]  —  74. 13°  ;  by  dilution,  nicotine  suffers  there- 
fore a  decrease  in  its  specific  rotation  which  amounts  to  more 
than  half  its  original  value. 

IV.   Ethyl  Dextrotartrate. 

The  preparation  used,  which  was  not  quite  pure,  gave  the 
following  specific  rotation  i1 

rfr          / 

,.,989          {    °-*>fdm  W  8-*9° 

I      0.4982       " 


a.     Mixtures  with  Alcohol. 
Specific  gravity  of  the  alcohol  d™  —  0.7962  : 


Mixture 
No. 

Ethyl  tartrate. 
P 

Alcohol. 
9 

d~ 

a.  for 
/=  2.199  dm. 

MS 

I 

77.98 

22.02 

1.0837 

I6.3I5C 

8.78° 

II 

35-74 

64.26 

0.9089 

6.87 

9.62 

III 

22.33 

77.67 

0.8634 

4.17 

9-85 

The  specific  rotation  increases  gradually,  therefore,  with  the 
amount  of  alcohol,  and  the  change  may  be  represented  by  a 
curve  of  very  slight  curvature  (Fig.  19)  which  almost  coin- 
cides with  a  straight  line.  For  the  formula  [a]  —  A  +  Bq 
there  follows  : 


From  mixtures    I  and    II          A  =  8.34 

II    "     III  8.52 

I    "      III  8.36 


=  -(-  O.OI98 
O.OIJO 
O.OI92 


and  in  the  mean, 


/>  =  8.41  -f  0.0187  q. 


The  formula  with  three  constants  gives  A  =  8.27°. 

1  The  imperfect  purity  of  the  substance  employed  was  without  consequence  for 
this  investigation.  One  could  just  as  well  take  a  mixture  of  the  active  body  with  any 
inactive  substance  as  a  basis,  and  determine  how  exactly  the  original  specific  rotation 
might  be  found  from  observations  on  solutions. 


1 86 


SPECIFIC   ROTATION 


Fig.  19. 
b.  Mixtures  with  Methyl  Alcohol, 


Mixture 
No. 

Ethyl  tartrate. 
P 

Methylalcohol. 
9 

df 

a  for 
/=  2.198  dm. 

E«]s 

I 

77.46 

22-54 

1.0882 

17.88° 

9-65° 

II 

56.65 

43-35 

1.0007 

12.97 

10.41 

III 

39.92 

60.08 

0.9381               8.98 

10.92 

IV 

26.97 

73-03 

0.8946              5.87 

11.07 

V 

15.31 

84.69 

0.8568              3.23 

II.  21 

The  slight  change  which  the  specific  rotation  of  the  ethyl 
tartrate  suffers  by  reason  of  the  presence  of  the  methyl  alcohol 
is  not  quite  proportional  to  the  dilution  but  may  be  represented 
by  a  curve,  at  first  rather  strongly  and  later  less  strongly 
inclined.  (This  does  not  show  in  the  figure  because  of  the 
small  scale  on  which  it  is  drawn.)  From  mixtures  I,  II,  and 
III  we  have 

[>]/>  =  8.42  +  0.0625  q  —  0.0003479  q\ 

the  constant  A  agreeing  fairly  well  with  the  rotation  of  the 
original   ethyl    tartrate.     If  we   use   for   the   calculation    the 


EXPERIMENTAL   PROOF   OF   BIOT'S   FORMULAS 


I87 


dilute  solutions  III,   IV,  and  V  we  obtain  A  =  10.25,  which 
differs  rather  widely  from  the  true  value  of  8.31. 

c.  Mixtures  with  Water 
These  were  polarized  immediately  after  making. 


Mixture 
No. 

Ethyl  tartrate. 

Water. 
Q 

rfr 

/  in  dm. 

Of 

Ms 

I 
II 
III 

69.69 

39-82 
13.89 

30-3I 
60.18 

86.11 

1.1508 
1.0884 
1.0292 

2.198 
2.199 
2.198 

24.68° 
19.27 
7.92 

14.00° 

20.22 
25.20 

The  very  strong  increase  in  the  specific  rotation  of  the  tar- 
trate on  addition  of  water  is  almost  proportional  to  the  amount 
of  the  latter  added.  For  the  constants  of  the  formula, 
[a]  =  A  -f-  Bq  we  obtain  : 

From  mixtures    I  and    II  A  =  7.69          B  =  -j-  0.2082 

II  "     III  8.66  0.1920 

"  "  I  "      III  7.92  0.2007 

and  in  the  mean, 

[«]  D  =  8. 09  -|-  0.2003?. 

The  marked  deviation  in  the  constant  A  from  the  specific 
rotation  of  the  original  tartrate  (8.31)  may  be  a  result  of  the 
beginning  saponification  of  the  latter.  After  forty-eight  hours, 
the  above  solutions  gave  rotations  smaller  by  o.  i  to  0.2°. 

From  the  above  investigations  with  turpentine,  nicotine, 
and  ethyl  tartrate  as  well  as  from  many  other  experiments,  the 
following  relations  have  been  established  : 

i .  The  specific  rotation  of  an  active  body  on  increasing  dilution 
with  an  indifferent  inactive  liquid  suffers  no  sudden  change,  but 
a  gradual  progressive  alteration.  Whether  the  latter  is  in  the 
nature  of  an  increase  or  decrease  depends  on  the  nature  of  the 
active  body  ;  thus,  oil  of  turpentine  and  ethyl  tartrate  on  being 
mixed  with  different  solvents  show  always  an  increase,  while 
nicotine  and  camphor  (for  which  experiments  follow  in  §53) 
show  a  decrease  in  the  specific  rotation.  But  on  one  and  the 
same  active  body  different  solvents  act  in  very  different  degrees, 
so  that  if  the  results  were  represented  graphically  curves 


i88 


SPECIFIC   ROTATION 


would  be  obtained,  which,  starting  from  the  origin  ,  of 
coordinates,  representing  the  rotation  of  the  pure  substance, 
would  radiate  from  each  other. 

The  weaker,  therefore,  a  solution  of  an  active  substance  is, 
the  greater  is  the  deviation  of  its  specific  rotation  from  that 
which  it  shows  in  pure  condition.  The  whole  of  the  changes 
which  have  been  found  here  may  be  shown  by  calculating 
from  the  interpolation  formulas,  the  limits  for^  =  o  (pure 
substance)  and  q  =  100  (maximum  of  dilution).  With  the 
bodies  investigated  we  obtain  the  following  numbers  : 


Active  substance. 

Solvent. 

MB 

Of  the  pure 
substance 
g  =  o. 

M£ 

For  maximum 
dilution 

g  =  100 

Difference. 

Turpentine  oil 
(left-rotating) 

alcohol 
benzene 
acetic  acid 

36.970 
36.97 
3689 

38.790 

39-79 
40.72 

+     1.82° 

4-    2.82 
+   3-83 

Turpentine  oil 
(right-  rotating) 

alcohol 

14.17 

15-35 

+    1.18 

Nicotine 
(left-rotating) 

alcohol 
water 

160.83 
161.29 

138.59 
74-13 

-  22.24 
-87.16 

Ethyl  tartrate 
(right-rotating) 

alcohol 
wood  alcohol 
water 

8.27 
8.42 
8.09 

10.19 
11.19 
28.12 

+    i.92 
+    2.77 
+  20.03 

It  appears,  therefore,  that  the  specific  rotation  of  an  active 
substance  is  changed  by  different  solvents  to  very  different 
degrees. 

2.  From  the  specific  rotation  of  a  number  of  solutions  it  is  possible 
to  calculate  that  of  the  pure  substance.  The  degree  of  certainty 
with  which  this  is  true  is  different  for  different  substances, 
and  is  dependent  on  the  following  conditions  :  a.  Upon  the 
extent  of  the  changes  made  in  the  specific  rotation  by  the 
inactive  solvent.  The  greater  these  are,  the  more  unfavorable 
in  general,  are  the  conditions  for  calculation  (as  in  the  case  of 
nicotine  for  example),  b.  Upon  the  manner  in  which  these 
changes  take  place  by  increase  in  the  amount  of  inactive 


EXPERIMENTAL   PROOF   OF   BIOT'S    FORMULAS  189 

solvent,  that  is,  upon  whether  they  may  be  represented  by  a 
straight  line,  or  by  one  more  or  less  strongly  curved,  c.  Upon 
the  concentrations  of  the  solutions  used.  The  stronger  these 
are  the  greater  is  the  certainty  in  the  calculations.  The  above 
investigations  show  that  in  cases  where  the  formula, 
[a]  =  A  -f  Bq,  is  applicable,  the  constant  ^4  agrees  accurately 
with  the  true  rotation  of  the  pure  substance  (or  within  a  few 
tenths  of  a  degree),  when  the  strongest  solution  contains  about 
50  per  cent,  of  active  substance.  If,  on  the  other  hand,  the 
use  of  the  formula,  [<*]  =  A  +  Bq  -f-  Cq*,  is  necessary,  vari- 
ations of  more  than  a  degree  can  appear  if  solutions  containing 
less  than  80  per  cent,  of  active  substance  are  taken  as  the 
basis  of  calculation. 

j.  In  the  calculation  of  the  original  specific  rotation  of  a  sub- 
stance, the  same  value  is  always  obtained  independently  of  which 
indifferent  liquid  is  employed  as  a  solvent.  The  numbers  found 
for  the  active  bodies  investigated  (the  constants  A}  are  given 
below  : 

I.    TURPENTINE  OIL  (LEFT). 

Directly  observed \_a]D  37-oi° 

Calculated  from   the  mixtures  with  alcohol "        3697     — 0.04° 

"       benzene "        36.97     — 0.04 

11  "         "  "  "       acetic  acid..  «'         36.89     +0.12 

II.    TURPENTINE  OIL  (RIGHT). 

Directly  observed "        14.15 

Calculated  from  the  mixtures  with  alcohol *'        14.17      —  0.02 

III.    NICOTINE  (LEFT). 

Directly  observed "  161.55 

Calculated  from  the  mixtures  with  alcohol "  160.83     —  0.72 

"  "         "  "         "     water "  161.29    — 0.26 

IV.    ETHYL  TARTRATE  (RIGHT). 

Directly  observed "  8.31 

Calculated  from  the  mixtures  with  alcohol "  8.27     — 0.04 

"     methyl  alcohol  "  8.42     +  o.n 

"             "         "            "         "      water "  8.09     —0.22 

The  differences  found  are  so  small  that  they  evidently  must 
be  results  of  errors  of  observation. 

#.  In  the  comparison  of  the  rotations  of  different  dissolved 
bodies,  only  those  values  may  be  used  which  hold  for  the  pure 


190  SPECIFIC   ROTATION 

substances,  that  is,  the  constants  A.  If  specific  rotations  which 
embrace  the  changes  due  to  the  solvents  be  taken  as  the  basis 
for  comparison,  possible  relations  will  appear,  the  less  dis- 
tinctly, the  weaker  the  solutions  from  which  the  numbers 
were  obtained. 

In  certain  cases  the  constant  A  can  have,  besides,  a  different 
meaning  from  that  of  simply  expressing  the  original  rotation 
of  the  single  molecules  of  the  active  body.  This  would  be 
true  when  the  active  substance  forms  definite  compounds  with 
the  solvent,  or  when  the  active  molecules  unite  to  form  aggre- 
gations which  as  such  possess  rotation.  See  §  63  and  64. 

53.  Determination  of  the  True  Specific  Rotation  of  Solid  Active 
Substances. — The  method  to  be  employed  here  is  suggested  by 
what  has  just  been  given.  First  of  all  it  is  essential  to  pre- 
pare solutions  of  the  greatest  possible  concentration,  and  as  the 
nature  of  the  inactive  solvent  is  immaterial  one  must  be  chosen 
which  best  permits  the  fulfilling  of  this  requirement.  With 
the  aid  of  such  a  solvent  it  is  necessary  to  prepare  at  least 
three  solutions  of  different  concentrations  and  to  determine 
their  rotating  power.  If  the  relation  between  the  specific 
rotation,  [a] ,  and  the  percentage  amount  of  the  solvent,  q,  be 
expressed  graphically  and  it  is  seen  that  the  three  points  lie  in 
a  straight  line,  that  is,  that  [«]  changes  directly  with  q,  then 
the  constant,  A,  calculated  from  the  formula  [<*]  ==  A  -f-  Bq 
will  express  the  specific  rotation  of  the  pure  substance.  But 
if  the  middle  point  lies  higher  or  lower  than  the  others  then  a 
larger  number  of  solutions  must  be  investigated  in  order  to 
establish  the  curve  as  completely  as  possible,  for  which  then  a 
corresponding  interpolation  formula  ([#]  ==  A  -f  Bq  -f-  Cft 
or  analogous  one)  is  to  be  calculated.  It  is  also  possible  to 
obtain  by  the  graphic  method,  that  is  by  prolonging  the  curve 
obtained  to  the  abscissa  q  =  o,  a  value  which  approximates 
more  or  less  closely  to  the  specific  rotation  of  the  pure  sub- 
stance. 

It  must  be  understood  that  numbers  obtained  by  such  extra- 
polations must  be  received  with  caution.  To  secure  greater 
certainty  it  must  not  be  neglected  to  carry  out  the  investiga- 
tion with  several  different  solvents;  if  the  values  so  found  for 


OF   SOLID   ACTIVE   SUBSTANCES  igi 

the  constant  A  agree  among  themselves  closely  the  mean  of 
these  will  be  taken  as  the  sought- for  specific  rotation  of  the 
substance,  but  if  they  do  not  agree  the  whole  calculation  must 
be  rejected. 

In  consequence  of  their  conditions  of  solubility  the  calcu- 
lation of  the  specific  rotation  of  the  original  substances  is 
made  very  difficult  in  many  cases.  According  to  experience 
as  referred  to  above  it  will  be  possible  to  obtain  reliable  num- 
bers only  in  such  instances  where  solutions  may  be  made  with 
at  least  50  per  cent,  of  active  substance,  and  where  further  the 
curve  of  rotation  obtained  does  not  vary  too  much  from  a 
straight  line.  With  all  difficultly  soluble  bodies  there  is  no 
prospect  of  finding  the  true  specific  rotation  in  pure  condition. 

As  an  illustration  of  obtaining  the  true  specific  rotation  of 
an  active  solid  substance,  a  series  of  experiments  with  ordinary 
camphor  may  be  given  here.  A  number  of  solutions  in  differ- 
ent liquids  were  made  and  from  these  the  following  figures 
secured  by  observation: 


Solvent. 

No  .of 
solu- 
tion. 

Camphor. 
P 

Solvent. 

q 

< 

a^for 

/=  2.1979  dm. 

Ms 

Acetic  acid. 

I 
II 
III 

65.2519 

39-7I83 
I5.88I9 

34.7481 
60.2817 
84.1181 

0.98983 
I.OII28 
1.03389 

72.II70 
41.652 
15.887 

50.801° 
47.181 
44.021 

Acetic  ether. 

I 
II 
III 

53.7260 
34.5489 
14.9221 

46.2740 
6545II 
85.0779 

0.93269 
0.91987 
0.90686 

58.492 
36.520 
15.290 

53-109 
52.283 
51.408 

Mono- 
chloracetic 
ether. 

I 

II 
III 

54.2184 

3I.3990 
14.2332 

45.7816 
68.6010 
85.7668 

1.04206 
1.08670 
I.I2243 

65.356 
38.340 
17.543 

52.631 
51-123 
49.961 

Benzene. 

I 
II 
III 

63.1250 

49-6359 
24.3169 

36.8750 
50.3641 
75.6831 

0.93067 
0.91920 
0.89910 

63.575 
47.097 
20.638 

49.236 
46.966 
,  42.948 

Dimethyl  - 
aniline. 

II 
III 

57.1519 
36.0428 
15.1028 

42.8481 
63.9572 
84.8972 

0.95997 
0.95914 

0.95813 

59-533 
35.151 
13.708 

49-370 
46.263 

1  43.101 

Methyl 
alcohol. 

I 
II 
III 

49-3866 

30.3I54 
11.2590 

50.6134 
69.6846 
88.7410 

0.88093 
0.85318 
0.82700 

46.840  ' 
26.820 
9.382 

48.996 
47-179 
45.844 

Alcohol. 

I 
II 
III 
IV 
V 

54.7281 
49.8142 
30.1620 
15.0920 
9.6883 

45.27I9 
50.1858 
69.8380 
84.9080 
90.3117 

0.8S02I 
0.87194 
0.84031 
0.81752 
o.Sf>943 

50.634 

44.806 

25.013 
11.840 

7.378 

47-823 

46.934 
44.901 
43-66i 
42.806 

1 92 


SPECIFIC    ROTATION 


Fig.  20. 

The  specific  rotations  with  all  these  solutions  decreases  as 
the  amount  of  solvent  increases,  but  in  very  different  degrees 
with  different  inactive  solvents.  The  graphic  illustration  (Fig. 
20)  shows  that  these  changes  may  be  represented  almost 
exactly  by  straight  lines  when  as  solvents  acetic  acid,  acetic 


OF   SOLID   SUBSTANCES 


193 


ether,  monochloracetic  ether,  benzene  and  dimethylaniline  are 
used;  the  formula,  [ar]  =  A  -f-  Bq,  is  then  applicable  in  these 
cases.  But  with  ethyl  alcohol  and  methyl  alcohol  the  devia- 
tion from  the  straight  line  is  too  large,  and  the  formula 
[or]  =  A  -f-  Bq  -f  Cf,  was  used  for  the  calculations. 

The  following  table  contains  :  (i),  the  values  obtained  for 
the  constants  A  and  B  from  the  different  solutions  ;  (2),  the 
mean  interpolation  formulas  calculated  from  these  ;  ( 3 ) ,  the 
calculated  specific  rotations  of  the  solutions  employed,  obtained 
by  these  formulas,  and  the  differences  between  these  and  the 
observation  values  given  in  the  preceding  table. 


i 

3 

Solvent. 

[*].=  A-Bg 

Means. 

Solu- 
tion 

[«]/> 

calcu- 
lated 

Difference 
from  obser- 
vations. 

Calculation! 
from             A 
solutions 

B 

Acetic 
acid 

land    II  55.73 
II  and  III  55.17 
I  and  III  55.58 

0.1418 
0.1326 
0.1373 

WD  =55-49 
—  0.13723? 

I 
II 
III 

50.72 
47.22 
43-95 

-0.39 
+  0.04 
—  0.07 

Acetic 
ether 

land    II  55.11 
II  and  III  55.21 
I  and  III  55.14 

0.04307 
0.04458 
0.04384 

!>]/?=  55-15 

—  0.04383? 

I 
II 
III 

53-12 
52.28 
5I-4I 

-f  o.oi 
o.oo 
o.oo 

Mono- 
chlor- 
acetic 
ether 

land    II 
II  and  III 
I  and  III 

55-65 
55-77 
55-69 

0.06608 
0.06769 
0.06677 

[>]/>  =  55.70 
—  0.06685  q 

I 
II 
III 

52.64 
51.12 
49-97 

-f  O.OI 
0.00 
-f  O.OI 

Benzene 

land    II 
II  and  III 
I  and  III 

55'  45 
54.96 
55-21 

0.1683 
0.1587 
0.1620 

[«]/>  =  55-21 
—0.1630?- 

I 
II 
III 

49.19 
47-00 
42.87 

—  0.05 
-r  0.03 
—  0.08 

Di- 
methyl- 
aniline 

land    II  55.68 
II  and  III  55.92 
I  and  III  55  76 

0.1472 
0.1510 
0.1491 

[«]/>  =  55.78 
—  0.1491? 

I 
II 
III 

49-40 
46.25 

43-13 

+  0.03 

—  O.OI 

+  0.03 

Methyl 

alcohol 
•    ill 

[a]/?  =56.15  —  0.1749? 
—  0.0006617  q* 

I 

Alcohol          III 
V 

O]/>  =  54.38  —  0.1614  q 
-f  0.0003690  q1  l 

II 
IV 

47-21 
43-33 

-f  0.28 
-0.33 

The  formula  [a] 
13 


A  + 


Bq  42.8799 

-^  gives   WD  =  54.83 -23V82^. 


194 


SPECIFIC    ROTATION 


If  we  compare  with  each  other  the  values  obtained  for  the 
constant  A,  from  the  different  solutions  an  agreement  is  found 
which,  in  consideration  of  the  great  extrapolations  necessary 
(from  q  =  o,  amounting  to  25  to  50  per  cent.),  must  be  con- 
sidered as  a  very  close  one  ;  we  can  look  upon  the  mean  of 
these  numbers,  therefore,  as  representing  the  true  specific 
rotation  of  the  pure  camphor.  The  values  for  B,  depending 
on  the  solvent,  vary  on  the  contrary,  very  greatly.  If  we 
calculate  from  the  formulas  the  specific  rotations  for  the  two 
limits,  g  =  o  and  q  =  100,  the  following  results  are  obtained, 
from  which  may  be  seen  to  what  extent  the  different  solvents 
influence  the  rotating  power  of  camphor  : 


Solvent. 

[a]  D  for  q  =  o 

=  AD 

Pure  substance. 

[tf]  D  for  q  =  loo 
Infinite 
dilution. 

Total 
change. 

«;«;  «;° 

41  8° 

11  7° 

oDO 
re   2 

co  8 

10'/ 

4      A 

Monochloracetic  ether 

OO"* 

55-7 
ec   2 

49.0 

78   Q 

6-7 

16  T. 

OO"* 

re    8 

o°-V 

i<j.^ 

Methyl  alcohol  

00-° 

«;6  2 

4u.y 

A  C     7 

14.  y 
IO  Q 

Alcohol             

Ou"« 

C./1  A 

^j-6 

lu.y 
j2   r 

34-4 

41.9 

1^O 

From  the  numbers  obtained  we  have  finally  as  the  original 
rotation  of  camphor  at  20°, 

[«]/>  =  55-4°, 
writh  a  mean  error  of  ±  0.4°. 

54.  Slight  Changes  in  Specific  Rotation  by  Variations  in  Concentra- 
tion.—Such  are  observed,  as  will  be  shown  later  in  the  chapter 
in  which  changes  in  the  rotation  are  more  fully  discussed,  in 
cases  in  which  an  action  of  the  solvent  on  the  active  body  is 
as  far  as  possible  excluded,  and  where,  therefore,  molecular 
aggregation,  dissociation  or  hydrolysis,  etc.,  can  not  take 
place.  A  body  of  this  kind  is  cane-sugar  for  which  Tollens1 
and  also  Schmitz2  have  shown  by  accurate  investigations  that 
the  specific  rotation  undergoes  a  slight  but  regular  increase 
with  decrease  in  the  concentration.  The  observations  of 

1  Tollens:  Ber.  d.  chem.  Ges.,  10,  1403  (1877). 
*  Schmitz:  Ibid.,  10,  1414. 


SLIGHT   VARIATIONS 


195 


Schmitz  which  were  carried  out  by  methods  described  in  Part 
IV,  using  a  Wild  and  also  a  half  shadow  polarimeter,  are  given 
here  as  an  illustration  of  careful  experiments  : 


Grams     i     Grams 

a30 

sugar  in       sugar  in        Specific 

UD 

W" 

Difference 

No. 

100  grams 
solution. 

100  cc.         gravity, 
solution. 

for 

P 

,=*       <? 

1  =  2  dm. 

Observed.  Calculated. 

Obs.—  Cal. 

I 

64.978 

85.543         L3I650     112.268° 

65.620°       65.619° 

-f  0.001° 

II 

54.964 

69.108         1.25732 

91.066 

65.888 

65.911 

—  0.023 

III 

39-978 

47.039         1.17664 

62.348 

66.272 

66.242     +  0.030 

IV 

25.002 

27.594         1.10367  '     36.670 

66.441 

66.448      —  0.007 

V 

16.993 

18.144         1-06777 

24.128 

66.448 

66.506      —  0.018 

VI 

lo.ooo        10.382       1.03820 

13.824 

66.574 

66.528     -f  0.046 

VII 

4.998 

5.087         1.01787 

6.776 

66.609 

66.526 

-0.083 

In  calculating  the  constants  of  the  formula  [«]  =  A  -f- 
Bq  +  C<f  the  solutions  I,  III  and  V  were  used,  then  II,  IV 
and  VI  and  the  mean  taken.  The  following  equations  were 
obtained  with  relation  to  the  percentage  amount  of  sugar,  /, 
and  that  of  the  water,  100  — p  =  q,  which,  as  seen  from  the 
table,  agree  very  well  with  the  observations : 

[«]™  =  66.510  -f-  o. 004504  /  —  0.0002805  p* 
[«]"  =  64.156  -f  0.051596  q  —  0.0002805  f 
The  investigations  of  Tollens1  which  embraced  an  examina- 
tion of  seventeen  solutions,  with/  =  3.8  to  69.2  led  to  these 
formulas: 

["]"  =  66.386  -f  0.015035  p  —  0.0003986 p1 
[a]^  =  63.904  +  0.064686  q  —  0.0003986  g2 
By  a  different  method  of  calculation  from  the  observations 
of  Tollens,  Th.  Thomsen2  derived  this  equation, 

[a]2  =  64.190  +  0.055212  q  —  0.0003134  (f 
the  constant  A  in  which  (64.190)  agrees  very  well  with  that 
of  Schmitz,  64.156.  We  can  therefore  look  upon  these  num- 
bers as  giving  with  considerable  certainty  the  specific  rotation 
of  cane-sugar  in  amorphous  dry  condition,  as  the  concentra- 
tions of  the  solutions  were  carried  to  an  extreme  degree. 

1  Tollens:  Ber.  d.  chem.  Ges.,  10,  1410  ;  17,  1757. 
-  Th.  Thomsen:  Ibid.,  14,  1651. 


196  SPECIFIC   ROTATION 

Experiments  which  were  carried  out  by  Biot1  and  later  by 
Tollens2  on  the  specific  rotation  of  cane-sugar  in  fused  condi- 
tion led  to  uncertain  results  because  of  beginning  decomposi- 
tion, and  can  not  be  used  therefore  to  control  the  above  results. 

55.  Specific  Rotation  in  Very  Dilute  Solutions. — If  the  rotating 
power  of  an  active  body  is  changed  by  some  effect  of  the  sol- 
vent, it  might  appear  possible  that  this  action  would  come  to  an 
end  after  a  certain  decrease  in  the  concentration  had  been  passed, 
and  consequently  that,  with  still  further  dilution,  the  specific 
rotation  would  remain  constant.  Such  an  effect  could  be 
produced,  for  example,  by  electrolytic  dissociation. 

Investigations  of  this  kind  offer,  in  general,  very  consider- 
able experimental  difficulties,  inasmuch  as  the  errors  of  obser- 
vation assume  a  great  importance  in  connection  with  the  small 
values  of  the  angles  of  rotation.  Thus  far,  but  a  few  sub- 
stances, partial  or  non-electrolytes,  have  been  tested  in  very 
dilute  solutions  with  reference  to  their  rotating  power. 

Tartaric  Acid. — The  specific  rotation  of  aqueous  solutions 
increases  with  the  dilution  and  according  to  Arndtsen3  may 
be  represented,  for  amounts  of  water  from  q  =  50  to  95  per 
cent. ,  by  the  formula  : 

[«]2  =  f-950  +  0.13030?. 

That  this  increase  in  the  specific  rotation  goes  still  further 
by  increase  of  q  from  95.28  to  99.65  has  been  shown  by  experi- 
ments undertaken  by  Pribram.4  But  this  no  longer  cor- 
responds to  a  linear  formula  as  pointed  out  by  Bremer,5  and  it 
appears  that  [#]  increases  more  rapidly  than  it  does  in  con- 
centrated solutions. 

Cane- Sugar. — A  number  of  investigations  have  been  carried 
out  on  the  rotation  of  this  substance  in  very  dilute  solutions. 
The  formula  of  Tollens  (§54)  for  concentrations  from 
p  =  69  to  4, 

[a]*  =  66.386  +  0.015035  p  —  0.0003986/, 
gives  at  first  an  increase  in  the  specific  rotation  when  the  con- 

>  Biot-  Mem.  de  1'Acad.,  13,  131  (1835). 

*  Tollens:  Ber.  d.  chem.  Ges.,  10,  1413  (1877). 

*  Arndtsen  :  Ann.  chim.  phys.,  [3],  54,  403  ;  Pogg.  Ann.,  105,  312. 
4  Pribram  :  Ber.  d.  chem.  Ges.,  20,  1846. 

*  Bremer  :  Rec.  Trav.  chim.  Pays-Bas.,  6,  258. 


MINIMUM    VALUE   OF   SPECIFIC  ROTATION  197 

centration  is  diminished  from  69  per  cent.,  and  reaches  a 
maximum  at  p  =  1 8. 86  per  cent.  (66.528°)  ;  there  is  then  a  de- 
crease, so  that  for/  =  i.i,  [<*]  =  66.402°.  Direct  experiments 
with  dilute  solutions1  with  p  =  10  to  i  per  cent,  of  sugar  gave  ir- 
regular values  between  [<*]  =  66.499°  and  66.276°,  the  varia- 
tions in  which  from  those  calculated  by  the  above  formula  lie 
within  the  errors  of  observations,  but  show  in  general  a  slight 
decrease.  Pribram2  in  dropping  from  p  =  3.659  to  0.222  in 
five  steps  found  a  continuous  decrease  in  the  specific  rotation 
from  [**]£  =  66.531°  to  66.213°.  On  the  other  hand,  Nasini 
and  Villavecchia3  observed  for  five  concentrations  lying  between 
p=  1.253  and  0.824,  a  regular  increase  from  [<*]£  =  67. 37° 
to  68.24°.  The  results  are  therefore  contradictory  ;  but  for 
practical  use,  the  Tollens  formula  may  be  looked  upon  as 
satisfactory  for  all  concentrations. 

Dextrose.  — According  to  Tollens*  the  formulas, 

Anhydrous  dextrose M />  =  52-5°  +  o.oi8796/>  -f  o.ooo5i68/2 

Dextrose  hydrate  .' [<*]£  =  47-73  +  0.015534^  +  0.0003883^, 

derived  from  concentrated  solutions,  satisfy  the  results  of 
observation  down  to  a  decreased  concentration  of  p  =  i. 

It  has  not  been  certainly  shown,  therefore,  with  any  of  the 
above  substances  that  the  character  of  the  curve  expressing 
the  dependence  of  the  specific  rotation  on  the  concentration 
undergoes  a  change  for  very  great  dilutions.  A  case,  on  the 
other  hand,  where  the  behavior  is  essentially  different  will  be 
discussed  in  the  following  paragraph.  (See  Nicotine.) 

56.  A  Minimum  Value  of  Specific  Rotation.— This  peculiar  phe- 
nomenon has  been  recognized  in  the  following  cases  : 

Nicotine,  dissolved  in  water.  As  already  shown  in  §52,  the 
specific  rotation  decreases  in  a  very  marked  degree  as  the  dilution 
increases,  and  this  was  followed  to  ?=  91  per  cent.,  at 
which  point  the  original  rotation  of  the  nicotine,  [«]  #  = 

-  161.55°   nad  sunk  to  — 75-53-     Pribram5  first  noticed  that 
when  q  is  increased  from  96  to  99  per  cent.,   an  increase  in 

1  Tollens  :  Ber.  d.  chem.  Ges.,  17,  1751. 
*  Pribram  :  Ibid.,  ao,  1848. 

3  Nasini  and  Villavecchia:  Wied.  Beib.,  16,  366. 

4  Tollens  :  Ber.  d.  chem.  Ges.,  17,  2238. 
6  Pribram  :  Ibid.,  ao,  1848. 


1 98 


SPECIFIC    ROTATION 


the  rotation  from  [ar]™  =  —  77.03°  to  —  79.32*  follows.  This 
behavior  has  been  more  fully  investigated  by  Hein,1  who 
determined  the  point  of  minimal  rotation  ;  he  employed  a 
sample  of  nicotine  with  [«]£  =  —  164.00°  and  examined  eight 
dilute  solutions  at  temperatures  of  5°,  15°  and  20°.  These 
tests  were  combined  with  a  series  of  cryoscopic  molecular 
weight  determinations  of  nicotine  (C10HUN2  =162)  in  the 
same  or  nearly  same  concentrations.  The  values  obtained  are 
the  following  : 


In  JOG  parts  by  weight. 

M5> 

Ms 

MS 

Molecular  weight 
determination. 

Nicotine. 
P 

Water. 

q 

Nicotine 
in  roo 
parts  of 
solution. 

Molec- 
ular 
weight 
found. 

Varia- 
tion 
front 
162. 

15.592 

84.408 

-  73.39° 

-76.18° 

-  77.59° 

I3-736 

275 

113 

II.  206 

88.794 

73-05 

75-96 

77.01 

11.512 

26l 

99 

10.258 

89.742 

72.78* 

75-59* 

76.89 

8.307 

235 

73 

8.307 

91.693 

73-07 

75.76 

76.84* 

5.700 

209 

47 

5.700 

94.300 

73.81 

76.00 

76.96 

3.016 

180 

18 

3.016 

96.984 

74.46 

76.27 

77.25 

2.042 

168 

6 

2.042 

97.958 

74-74 

76.35 

77.32 

1.225 

165 

3 

1.061 

98.939 

74-79         76.83 

77.66 

0.346 

163 

i 

It  appears,  therefore,  that  at  the  temperatures  of  5°  and  15° 
a  minimum  specific  rotation  (marked  *)  occurs  when  the 
amount  of  nicotine  is  about  10  per  cent. ,  and  at  a  temperature 
of  20°  this  minimum  is  found  in  the  solution  of  about  8  per 
cent,  strength.  From  the  molecular  weight  determinations  it 
is  seen  that  nicotine  in  very  dilute  solutions  is  present  as  a 
normal  molecule  while  in  the  more  concentrated,  hydrates  and, 
likely,  molecular  aggregations  exist.  To  these  a  much  lower 
rotating  power  must  be  ascribed  than  to  the  pure  nicotine, 
but  if  these  are  broken  up  by  increasing  dilution,  as  suggested 
by  the  decrease  in  the  molecular  weight,  more  and  more  fresh 
nicotine  appears  by  which  the  decrease  in  the  specific  rotation 
is  gradually  arrested  and  finally  an  increase  in  the  rotation 

1  Hein  :  "Ueber  das  specifische  Drehungsvermogen  und  das  Moleculargewicht  des 
Nicotins  in  l,6sungen."  Inaug.  Diss.  Berlin,  1896.  (Investigations  carried  out  in  the 
author's  laboratory.) 


MINIMUM    VALUE   OF   SPECIFIC   ROTATION 


199 


must  follow.     In  this  manner  it  may  be  possible  to  explain  the 
occurrence  of  the  minimum  in  the  case  in  hand. 


77.8 


77.6 


Per  cent,  of  water. 
85 


51 


90  100 

Per  cent,  of  acid. 

Minimum  at  63.5  per  cent.  acid. 
Fig.  21. 

In  Fig.  21,  above,  the  rotation  for  20°  is  graphically  shown. 

Camphor,  dissolved  in  isovaleric  or  caproic  acid.  The  follow- 
ing solutions  have  been  investigated  by  H.  Vogel1  and  a  mini- 
mum rotation  (*)  found  for  large  concentrations  : 

1  H.  Vogel:  "Ueber  das  optische  DrehungsvermogendesCamphers."  Inaug.  Diss. 
Berlin.  (Investigations  carried  out  in  the  author's  laboratory.) 


200 


SPECIFIC    ROTATION 


Isovaleric  acid. 

Caproic  acid. 

Camphor. 
P 

Val.  acid. 
Q 

Ms 

Camphor. 
P 

Capr.  acid. 
1 

Ms 

52.37 

47-63 

+  53.43° 

49.84 

50.16 

+  53-67° 

46.71 

53.29 

53.29 

47-88 

52.12 

53-63 

43-03 

56.97 

53.16 

43.30 

56.70 

53-46 

38.55 

61-45 

53-10* 

36-48 

63-52 

53.22* 

36.71 

63.29 

53.2° 

26.19 

73.81 

53.42 

32.22 

66.78 

53.28 

18.49 

81.51 

53-70 

27.06 

72.94 

53-40 

8-53 

91.47 

56.51 

18.28 

8t.72 

54-51 

2.31 

97.69 

67.19 

12.63 

87.37 

56.02 





— 

9.46 

90.54 

58.17 





— 

4.36 

95.64 

68.41 





— 

3.05 

96.95 

76.44 





— 

As  seen  from  the  above  numbers,  and  also  from  the  graphic 
illustration  in  Fig.  21,  the  specific  rotation  of  the  camphor 
decreases  at  first  in  very  slight  amount,  from  the  point  of 
greatest  concentration  on,  with  an  increase  in  the  percentage 
of  acid,  but  reaches  a  minimum  when  the  amount  of  iso valeric 
acid  is  61.45  Per  cent,  or  the  amount  of  caproic  acid  is  63.52 
per  cent.  Then  a  slow  increase  in  the  rotation  begins,  and 
only  after  considerable  dilution  does  a  sudden  and  marked 
change  appear.  Corresponding  to  the  minimum  point  in  the 
rotation  there  is  no  simple  molecular  proportion  between  the 
amounts  of  acid  and  camphor.  The  dependence  of  the  specific 
rotation  on  the  amount  of  acid  can  be  represented,  according 
to  Vogel,  by  the  following  formulas  : 

Isovaleric  acid [or]  ^  =  57.15  —0.12572  q  -\-  o.ooiooo?2 

Caproic  acid [**];?  — 58.90 —  o.  16846^  -\-  o.ooi 279  q1 

Solutions  of  camphor  in  other  fatty  acids  do  not  exhibit  the 
appearance  of  a  minimum  or  a  great  increase  in  the  specific 
rotation  with  strong  dilution,  but  [or]  decreases  regularly  with 
increased  addition  of  acid,  as  was  true  with  the  solvents 
described  in  §  53.  Vogel  gives  the  following  observations: 


REVERSAL  IN  THE  DIRECTION  OF  ROTATION 


201 


Formic  acid. 

Acetic  acid. 

Propionic  acid. 

N.  Butyric  acid. 

q 

MS 

• 

E*» 

Ms 

q 

Ms 

35-89 

+  39-93c 

47.25 

+  49-37° 

60.92 

+  50.53° 

49.10 

+  52.49° 

49.11 

35.o8 

61.16          47.20 

69.40 

49.70 

63.07 

51.35 

57.68            32.38 

65-65 

46.60 

76.93 

48.98 

68.39 

50.94 

65.62             29.85 

70.40 

45-93 

86.30 

48.34 

76.76 

50.07 

75.95            26.91 

80.78 

44-24 



— 

88.34 

49.67 

79.56            26.03 

83-58 

43-87 

.... 

— 

93-44 

49-56 



9i-5o 

43.36 

.... 

.... 

.... 

.... 

The  effect  of  these  fatty  acids  on  the  original  rotation  of  the 
camphor  (+  55.4°)  is  decreased,  as  easily  seen,  with  increased 
molecular  weight  of  the  acids.  It  is  not  clear  upon  what  the 
peculiar  behavior  of  the  valeric  and  caproic  acids  depends. 

57.  Reversal  in  the  Direction  of  Rotation  by  Change  in  Concentra- 
tion.— In  the  case  of  bodies  whose  specific  rotations  decrease 
with  increase  in  the  amount  of  solvent,  it  may  happen  that  the 
rotation  will  sink  to  zero  and  then,  with  increased  dilution, 
rise  in  the  opposite  direction. 

This  behavior  was  first  noticed  by  Schneider1  in  aqueous 
solutions  of  ordinary  malic  acid  and  some  of  its  salts,  for 
which  the  following  results  were  obtained: 


Malic  acid. 


'Sodium  acid  malate.       Sodium  malate.         Barium  malate. 


9 

MS 

q 

Ms 

q 

MS 

q 

Ms 

29.88 

+  3-34° 

39-45 

-f  0.15° 

34-47 

-f  4.72° 

90.62 

+  1.81° 

40.01 

-7-231 

50.46 

—  1.71 

44-74 

+  2.15 

91.50 

+  1.61 

50.13 

+  1.38 

60.28 

-3.27 

51.21 

+  0.50 

95-01 

4-  0.54 

53-53 

-f  i.  oo 

69-98 

-4.26 

53-16 

—  0.16 

98.04 

—  O.II 

62.47 

+  0.17 

79.81 

-5-57 

57.78 

-  1.26 





63.34 

+  0.09 

80.05 

-  5-64 

66.09 

-3.43 





64-74 

—  0.04 



.... 

70.01 

-4-34 





70.31 

—  0.34 

.... 

.... 

74-73 

-5.28 

.... 



70.94 

—  0.63 





85.34 

-6.98 

.... 



83.35 

-1.58 



.... 

94.73 

-8.39 





Qi.68 

-  I'lo 

1  G.  H.  Schneider:  Ann.  Chem.  (I^iebig),  307,  257. 


202 


SPECIFIC    ROTATION 


The  relation  of  the  specific  rotation  to  the  amount  of  water, 
g,  can  be  expressed  by  the  formulas, 

Malic  acid [a]  ™  =    5.89  —  0.0896  q 

Sodium  acid  malate [**]/>  —    9-37 — 0.2791  q  +  0.001152  q~ 

Sodium  malate [or] "°  =  15. 20  —  0.3322  q  -f  0.000814  q'1, 

from  which  by  taking  A  -f  Bq  -f  Cq*  =o,  the    values  of  q 
are  obtained  at  which  the  solution  becomes  inactive. 


Malic  acid. 
q  =  65.76 


Sodium  acid  malate.         Sodium  malate. 
40.25  52.57 

A  change  in  the  direction  of  rotation  does  not  occur  with 
the  other  alkali  malates  ;  they  all  exhibit  increasing  left 
rotation  with  changes  in  concentration  from  greatest  strength 
to  extreme  dilution. 

The  causes  on  which  these  changes  possibly  depend  are 
explained  in  §63. 

The  same  phenomenon  has  been  observed  with  /-sodium 
lactate  dissolved  in  alcohol  (Purdie  and  Walker),1  and  with 
aqueous  solutions  of  the  barium  salts  of  ^-methoxysuccinic 
acid  (Purdie  and  Marshall)2  and  ^-ethoxysuccinic  acid  (Purdie 
and  Walker).3  This  may  be  seen  from  the  following  table  in 
which  c  is  the  number  of  grams  of  active  substance  dissolved 
in  100  cc.  of  solution.  At  the  foot  of  the  table  are  given  the 
concentrations  corresponding  to  the  inactive  points  : 


/-Sodium  lactate 
(in  alcohol). 

rf-Barium  methoxysuccinate 
(in  water). 

d-Barium  ethoxysuccinate 
(in  water). 

c 

MS 

c 

MS 

c 

M*9 

23.21 

—     2.28C 

26.13 

-  14.27° 

21.48 

-4.37 

19.79 

-      2.22 

12.42 

-  7-36 

10.77 

+  2.46 

11.20 

-     0.80 

5-75 

2.21 

4.56 

+  6.37 

9.29 

-     0.48 

MS 

+     3.16 

. 

7-47 

-f    1-34 

.    . 

. 

5-60 

+    2.50 

. 

.    . 

. 

2.24 

+    8-93 

. 

.    . 

. 

1.  12 

f  10.36 

. 

.    . 

. 

0.56 

+  20.53 

• 

•    • 

• 

•  • 

8.81 

0 

3.85 

o 

14.63 

0 

1  Purdie  and  Walker:    J.  Chem.   Soc.,  67,  631.    In  the  original,    the  values  of 
—  [a]  are  given. 

2  Purdie  and  Marshall  :  J.  Chem.  Soc.,  63,  227. 
•  Purdie  and  Walker  :  Ibid.,  63,  235. 


INCREASE  OR  DECREASE  IN  SPECIFIC  ROTATION. 


203 


A  change  of  sign  takes  place  with  the  following  substances, 
investigated  by  Freundler,1  when  they  are  brought  from  the 
pure  condition  (Y  =  100)  into  solution: 


d-Propyl  dicaproyltartrate. 


rf-Ethyl  diacetyltartrate 
in  chloroform. 

In  bromoform. 

In  benzene. 

c 

M. 

c 

[«}. 

c 

M, 

100 

-f    5-o° 

100 

+  2.2° 

100 

+  2.2° 

50 
40 

30 

-    5-3 
-    5-9 
-    6.5 

23.16 

5.88 
2.39 

-5.2 

—  8.0 

19-59 
10.83 

5-45 

—  2.O 

-3-6 

-4-3 

20 

-    7.1 

— 

1.54 

-5-4 

IO 

5 

-    7-5 
—    8.8 

.... 

.... 

... 

2.5 

—  10.0 

— 



... 

58.  Increase  or  Decrease  in  Specific  Rotation  with  Increasing  Dilu- 
tion of  Solutions. — As  shown  by  the  examples  thus  far  given 
with  some  substances  there  is  an  increase,  and  with  others  a 
decrease  in  the  specific  rotation  as  the  amount  of  solvent  is 
increased.  In  order  to  show  at  a  glance  the  relations  found,  a 
number  of  observations  are  given  in  diagram  form,  the  increase 
or  decrease  of  rotation  being  indicated  by  the  direction  of 
arrows.  The  solvents  used  are  given  in  parentheses:2 


A.  Increase  in  Rotation. 
i.  Active  Acids  and  Their  Salts. 

</-Tartaric  acid   (water) 

^-Sodium  tartrate,  neutral  (water) 

^-Thallium-potassium  (Na,  Li,  NH4)   tartrate  (water) 

*/-Ethylenediamine  tartrate   (water) 

</-Ethyl  tartrate  (water,  methyl-ethyl  alcohol ) 

ff-Diacetyltartaric  acid  anhydride  (acetone,  benzene) 

*/-Dibenzoyltartaric  acid  anhydride  (acetone,  alcohol) 

</-Dibenzoyltartaric   acid  (alcohol) 

rf-Dibenzoyltartaric    acid,      dimethyl     and  diethyl    esters 

( alcohol ) 

^-Propyldicaproyl  tartrate  (carbon  disulphide) 

1  Freundler:  Ann.  chim.  phys.,  [7],  4,  252. 

2  The  observations  on  which  the  table  is  based  are  given  in  Part  VI. 


-o°  + 


204  SPECIFIC    ROTATION 


i.  Active  Acids  and  Their  Salts.     (Continued.) 
{/-Lactate  of  K,  Na,  Cd  (aqueous  alcohol) 
/-       "        "  K,  Na,  Li,  Ca,  Zn  (aqueous  alcohol) 
Glucuronic  acid  and  K-salt  (water) 
Podocarpate  of  sodium   (water) 
C  holalate  of  Na  and  K  ("water) 

2.  Active  Bases  and  Their  Salts. 
Quinidine  (alcohol) 

hydrochloride,  sulphate  (water,  alcohol) 
Cinchonine  (alcohol  +  chloroform  ) 

hydrochloride,  sulphate  (water,  alcohol) 
Apocinchonine  hydrochloride  (water) 
Quinamine  (alcohol,  ether,  chloroform) 
Conquinamine  (alcohol,  benzene) 
Quinicine  oxalate  (alcohol  4"  chloroform) 
Laudanosine    (alcohol  ) 
/-Cocaine  hydrochloride    (alcohol) 

Cupreine  hydrochloride,  hydrobromide,  sulphate  (water) 
Quinine  anhydride  and  hydrate  (  alcohol  ) 

"     hydrochloride,  sulphate  (  water,  alcohol) 
Cinchonidine  (alcohol) 

hydrochloride,  sulphate  (water) 
Hydrocinchonidine  hydrochloride  (water) 
Morphine  hydrochloride,  sulphate  (water)  .... 
Pseudomorphine  hydrochloride  (water) 
Thebaine  hydrochloride  (water) 
Strychnine   (chloroform) 
Brucine  (chloroform) 
/-Cocaine  (chloroform)  ................................. 


3.  Sugar  Group. 

Cane  sugar  (  water  ) 
Maltose  (water) 
Salicin  (water) 

4.  Aromatic  Substances. 

{/-Pinene  (alcohol) 

/-  "  (alcohol,  acetic  acid,  benzene) 
/-Menthol  (  alcohol,  acetic  acid,  benzene) 
a-Nitrocamphor  (benzene) 

B.  Decrease  in  Rotation. 
i.  Active  Acids  and  Their  Salts. 

{/-Potassium  tartrate,  neutral  (water) 
^/-Sodium  acid  tartrate  (  water) 


—  Oc 


INCREASE  OR  DECREASE  IN  SPECIFIC  ROTATION 


205 


i.  Active  Acids  and  Their  Salts.     (Continued.}  —  o°  -+- 

{/-Sodium  borotartrate  ( water) 

{/-Diacetyltartaric  acid    (water,  alcohol ) 

{/-Di-i-butyldiacetyl  tartrate    ( alcohol) 

{/-Mandelic  acid  (water) 

/-Mandelic  acid   (water) 

{/-Camphoric  acid  (alcohol,  acetone,  acetic  acid ) 

{/-          "  "     salts  (water) 

Quinate  of  Ba,  Sr,  Ca,  Mg,  Zn  (water) 

Shikiminic  acid  ( water) 

Sodium  santoninate  (water) 

Cholalic  acid  (alcohol ) 

2.  Active  Bases  and  Their  Salts. 

{/-Conine  (alcohol,  benzene) 

{/-       "      hydrochloride,  hydrobromide,  acetate  (alcohol) . .  • 

Nicotine  (water,  alcohols,  aniline,  toluidine) 

4 '       hydrochloride,  sulphate,  acetate  (water) 

Benzoylcinchonine  (alcohol) 

/S-Isocinchonine  (plcohol) 

14  hydrochloride  (water) 

Hyoscyamine  (alcohol) 

3.  Sugar  Group. 

Dextrose  (water) 

Xylose  (water) 

Rhamnose  ( water) 

Levulose  (water) 

Phloridzin  (alcohol) 

4.  Aromatic  Substances. 

{/-Camphor   (alcohols,  fatty  acids,   ethyl  acetate,   benzene, 

dimethyl  aniline) 

Cholesterol  ( chloroform ) 


In   general  the  following  points  are  shown  by  the  above 
table: 

1 .  With  the  active  acids  and  their  salts  there  is  observed  an 
increase  as  well  as  a  decrease  in  specific  rotation;  bodies  as 
closely  related  as  potassium  tartrate  and  sodium  tartrate  show 
opposite  behaviors. 

2.  With  the  alkaloids  and  their  salts  increase  in  the  rotation 
is  the  usual  phenomenon. 

3.  Among  bodies  of  the  sugar  group,   the  monosaccharides 
appear  to  show  a  decrease  and  the  disaccharides  an  increase. 


206 


SPECIFIC    ROTATION 


Further,  it  is  to  be  noticed  that  different  solvents  exert  the 
same  action  on  many  of  the  above  bodies. 

An  explanation  of  these  phenomena,  as  far  as  it  is  now 
possible,  will  be  given  in  §61  to  §66. 

B.  Dependence  of  the  Specific  Rotation   on  the  Nature  of  the  Solvent. 

59.  If  equal  weights  of  an  active  body  are  dissolved  in 
different  inactive  liquids,  the  specific  rotation  can  assume  very 
different  values  depending  on  the  manner  in  which  the  solvent 
behaves  with  the  substance.  Several  illustrations  of  this  have 
been  given  in  former  chapters  ;  a  number  of  observations 
follow  in  which  this  variation  comes  strongly  into  view. 

Freundler1  found  the  following  figures  for  some  substituted 
tartaric  acid  esters  in  solutions  of  concentration,  c  •=  5  to  6  : 


N.  Propyl 
diacetyl- 
tartrate. 

M» 

N.  Propyl 
dibutyryl- 
tartrate. 

M« 

N.  Propyl 
dicaproyl- 
tartrate. 

M. 

-\-  l^  ^0 

4-    «:  2° 

4-22° 

Solution  in  : 

T  i6-o 
_l_  -16  7 

T        O"* 

4-  28  8 

4-  27  •> 

Methyl  alcohol     

1     Ou'/ 

1    II  I 

4-      Q   T. 

1        ^  4 

1    A*'1 
+  IO  4. 

V'O 

4-72 

4-    «;  •; 

jjthvl  alcohol    

+      Q  6 

4-    6  a 

4-^6 

y.w 

-4-86 

"•o 
4-    «  « 

o-u 
4-    2  d 

-1-    8  «; 

I      j-j 

4-    -z  8 

_|_     i  -i 

I     °-o 
4-64 

o<u 

+      2  7 

Monochlorethylidene  chloride  •  . 

+    6.4 
4-    6  2 

+      2.3 
4-26 

4-    0.6 

O  2 

Methylene  chloride  • 

!      «••• 

_1_      c  7 

4-28 

o-  / 

1        C    1 

1        1  I 

1       n  1 

I      !>-j 

4-47 

O'1 
+      1  7 

I       u-»5 

4-    a  8 

4-    06 

I   Q 

1      O'° 

_l_       7    A 

4-    06 

•"••7 

2  I 

Metliylene  bromide  

\       O-4 

_|_      T   7 

4-      2'd 

*••  1 
+      T    2 

I   A 

J  .4 
+      1   2 

1.4 
O  I 

4-3 

A  O 

2  6 

-    a  8 

71 

0'° 

7-1 

It  is  apparent  that  the  specific  rotations  of  the  original  sub- 
stances are  sometimes  increased,  and  sometimes  diminished  by 

1  Freundler:  Compt.  rend.,  117,  556;  Ann.  chim.  phys.,  [7],  4,  244. 


DEPENDENCE  ON  TEMPERATURE  2Oy 

the  inactive  liquids,  and  further,  that  the  order  in  which  the 
solvents  stand  with  reference  to  their  action  is  almost  the  same 
for  the  three  substances. 

Even  bodies  which  exhibit  but  slight  changes  in  specific 
rotation,  such  as  cane-sugar,  show  quite  appreciable  deviations 
when  dissolved  in  different  liquids.  Tollens1  investigated  solu- 
tions of  the  following  composition  : 

10  parts  sugar  —  90  parts  water [or]  D  =  +  66.67° 

C  ethyl  alcohol  "  =  -p  66.83 

10  "  "  -f  23  "  "  -f  67  parts  •{  acetone "  =--  +  67.40 

I  methyl  alcohol  "  =  —  68.63 

It  may  also  happen  that  a  change  in  the  direction  of  rotation 
can  take  place  by  application  of  different  solvents.  Illustra- 
tions of  this  have  been  shown  by  tables  already  given,  and 
others  are  furnished  by  substances  described  below. 

d-  Tartaric  Acid,  which  rotates  to  the  right  when  dissolved  in 
water,  exhibits  left-rotation  when  dissolved  in  a  mixture  of 
acetone  and  ether  (Landolt).2  Pribram3  found  very  marked 
variations  by  use  of  the  following  liquids  in  which  the  amount 
of  substance  dissolved  was  always  5  grams  to  make  100  cc. 

Solvent:  [>]" 

Water -f  14.40° 

Alcohol * -f-    3.79 

Equal  vols.  of  alcohol  and  mononitrobenzene -+-    3.17 

"        "     "  "         "    nitroethane +    3-°9 

"        "     "  "         "    mononitrotoluene -    0.69 

"     "  "         "    ethylbromide -    3.62 

"     "  "         "    benzene -    4." 

"        "     "  "         "    toluene -    6.19 

"     "  "         "    xylene -    6.52 

"        "     "  "         "    cymene -    7.91 

"        "     "  "         "    monochlorbenzene -    8.09 

As  far  as  explanations  of  this  behavior  are  possible  they 
will  be  given  in  the  chapter  on  the  causes  of  changes  in 
specific  rotation,  §  61  to  65. 

C.  Dependence  of  the  Specific  Rotation  on  the  Temperature. 
60.  Increase  of  temperature  affects  different  active  bodies  in 

1  Tollens  :  Ber.  d.  chem.  Ges.,  13,  2303. 

2  I^andolt:  Ibid.,  13,  2332. 

3  Pribram:  Ibid.,  22,  6. 


208  SPECIFIC    ROTATION 

different  ways;  with  some  there  is  an  increase,  with  others  a 
decrease  in  the  rotation  and  in  different  degrees. 

Among  active  crystals,  as  remarked  in  §  44,  only  quartz  and 
sodium  chlorate  have  been  investigated  in  this  direction. 
With  both,  an  increase  in  the  rotation  follows  on  warming. 
The  change  here  is,  therefore,  the  reverse  of  that  in  the  ordi- 
nary refraction  of  light  which  is  diminished  by  increase  of 
temperature. 

Liquid  Active  Bodies. — If  such  a  substance  is  contained  in  an 
observation  tube,  which,  to  accommodate  expansion,  is  fur- 
nished with  a  lateral  opening,  then  on  application  of  heat  the 
density  must  decrease  and  consequently  the  number  of  mole- 
cules in  the  active  column,  causing  a  diminution  of  the  angle 
of  rotation.  But,  on  the  other  hand,  the  length  of  the  tube 
has  increased  which  exerts  an  action  of  the  opposite  kind.  In 

calculating  the  specific  rotation,  [or]  =  - — -> 'these  influences 

are  eliminated  if  density  and  length  of  tube  are  found  for  the 
same  temperature  at  which  the  rotation  is  determined,  and  in 
case  these  alone  come  into  question  the  values  for  [or]  should 
remain  constant.  But  according  to  experience  this  is  not  quite 
true  in  the  case  of  any  known  body,  and  it  follows  that  heat 
must  exert  some  special  effect  on  optical  activity. 

On  the  effect  of  temperature  on  bodies  which  are  in  them- 
selves liquids  we  have  but  few  observations. 

Increase  in  specific  rotation  with  increase  in  temperature  has 
been  found,  for  example,  in  the  following  bodies: 

a.  Nicotine,  left-rotating. — According  to  investigations  of 
Landolt1  which  are  here  given  in  full  to  illustrate  the  changes 
in  the  different  factors  observed,  there  were  found: 

Temp.  I  d4  I  Of/)  [a]z> 

10.2°  1.01837  99-9I4*  —  163.776°  -  160.96° 

20.0  I.OIIOI  99-923  —  163.204  —  l6l.55 

30.0          1.00373         99-9322          -  162.450  -  161.96 

It   is  seen    that  while  the  angle    of    rotation  has    become 

1  I^andolt:  Ann.  Chem.  (I<iebig),  189,  319  (1877). 

2  Calculated  from  the  length  measured  at  20°  by  aid  of  the  coefficient  of  expan- 
sion, 0.0000086. 


DEPENDENCE  ON  TEMPERATURE  209 

smaller  with  increasing  temperature,  the  specific  rotation,  on 
the  contrary,  has  grown.  The  increase  is  small  and  amounts 
to  about  0.05  for  i°. 

b.  The  left-rotating  esters  of  gly  eerie  acid  and  diacetyl  glyceric 
acid  show  also  an  increase  in  [<*]/>,  according  to  Frankland  and 
MacGregor,1  and  for  ordinary  temperatures  the  following 
amounts  for  i°  : 

.  (  methyl  .  .  .  0.016° 
Glycerate  of  {  *  isopropyl    .  .  .  0.065° 

meth  1        oo-  Diacetyl-    1  isobutyl  .....  0.054 

Diacetyl-       j  ™*    y  '       ^3        glycerate  of  j  N-heptyl  .....  0.067 

glycerate  of     \  N  ;  Q  L  N-octyl  ......  0.043 


c.  For  the  right-rotating  esters  of  tartaric  add,  Pictet2  found  : 

Temperature. 

20°  100° 

Methyl  tartrate  .....    \oi\  D  =  -f    2.14          [a]  D  —  +    6.00 

Ethyl  tartrate  .......        "     =  -f    7.66  "     =+13.29 

N-propyl  tartrate  ....        "       -  —  12.44  "     =  +  I7-11 

I-propyl  tartrate  .....        "     =4-14.89  "     =4-18.82 

If  the  increase  in  [a]  was  proportional  to  the  change  in 
temperature  it  amounted  to  about  0.05  to  0.07  for  i°. 

d.  An  increase  in  the  angle  of  rotation  has  been  found  in  the 
following  bodies:  ' 

Right-rotating  isobutyl  isoamyloxide  (Le  Bel3  and  Colson),4 
di-isoamyl  oxide  ..................  (Colson),* 

"  methyl  isoamyloxide  ..........  ----  (  Colson),4 

amyl  acetate  ......................  (  Colson)  ,5 

Left-rotating  methyl  lactate  .....................  (Le  Bel).3 

With  reference  to  the  question  whether  the  change  in  rota- 
tion could  follow  from  polymerization  with  lower  temperature, 
LeBel6  observes  that  according  to  the  investigations  of  Ramsay 
(  i  )  ethyl  tartrate  possesses  the  simple  molecular  weight  for 
all  temperatures,  (2)  the  same  is  true  of  isobutylamyl  oxide 
between  —  23°  and  -f-  125°,  (3)  that,  on  the  other  hand,  propyl 

1  Frankland  and  MacGregor  :  J.  Chem.  Soc.,  65,  760  (1894). 

2  Pictet:  Arch,  de  Geneve,  [3],  7,  82  (1882). 

3  I^eBel:  Compt.  rend.,  118,  916  (1894). 

4  Colson:  Ibid.,  116,  319  (1893). 

5  Colson:  Ibid.,  119,  65,  1894.    From  the  papers  of  LeBel  and  Colson,  it  is  not  clear 
whether  the  data  refer  to  the  observed  angle  of  rotation  or  to  the  specific  rotation. 

6  I^eBel:  Compt.  rend.,  118,  916;  119,  226  (1894). 

14 


2IO  SPECIFIC    ROTATION 

glycol  has  the  double  molecular  weight  above  100°  and  the 
quadruple  weight  at  the  ordinary  temperature,  without  show- 
ing any  change  in  activity  corresponding  to  this  polymerization. 
This  supposed  cause  appears  therefore  to  be  insufficient. 

A  decrease  in  specific  rotation  with  elevation  of  temperature 
was  observed  by  Gernez1  in  several  essential  oils.  It  was  found 
that  the  decrease  could  be  expressed  by  the  following  formulas, 
holding  from  o°  to  150°: 

Right  turpentine  oil [or]  D  =    36.61  —  o. 0x54437  / 

Orange  oil [/*]/>  =  II5-3I  —  0-1237  /  —  o.o4i6  P 

Bitter  orange  oil [«]  D  —  118.55  —  0.1175  /  —  o.o.22i6  & 

The  decrease  goes  still  further  when  the  temperature  of  the 
boiling-point  is  passed  and  the  body  becomes  a  vapor  (see  §  9). 
On  the  other  hand,  as  Gernez  found,  the  dispersion  suffers  no 
marked  change  by  heat. 

Dissolved  Active  Bodies. — As  experiment  has  shown,  with 
these  also  there  may  be  a  change,  not  only  in  the  observed 
angle  of  rotation,  but  in  the  specific  rotation,  which  may 
undergo  either  an  increase  or  decrease  by  change  in  tempera- 
ture. In  the  following  table  in  which  bodies  already  men- 
tioned are  included  (and  marked  with  an  *)  all  the  known 
relations  are  given: 
CHANGE  IN  THE  SPECIFIC  ROTATION  WITH  INCREASED  TEMPERATURE. * 


Increase  in  left  rotation  +~m 

*Nicotine 

*Esters  of  glyceric  acid 

*Esters  of  diacetylglyceric  acid 

Malic  acid  in  dilute  aqueous  solution 


••—Decrease  in  right  rotation 
*Right  turpentine  oil 
*Orange  oil 
*Bitter  orange  oil 
Malic  acid  in  strong  solution 
Cane-sugar  in  water 
Milk-sugar    "       " 
Maltose         "       " 
Galactose      "       " 
Atabinose     "       " 
Rhamnose    "       " 
Cinchonicine  in  alcohol 
Quinidine         "         " 
Quinidine  sulphate  in  water 
Tartar  emetic  "       " 

1  Gernez:  Ann.  de  1'Ecole  normal,  i,  i  (1864). 

1  The  extent  of  the  changes  in  the  rotation  of  the  different  substances,  as  far  as 
observations  reach,  will  be  given  in  the  chapter  on  "Constants  of  Rotation." 


DEPENDENCE  ON  TEMPERATURE 


211 


-  o°  - 


Decrease  in  left  rotation  »-»• 

Turpentine  oil 

Fructose  (levulose)  in  water 

Invert  sugar 

Saccharin 

Mandelic  acid 

Sodium  santoninate    "      " 

Quinine  in  alcohol 

Quinine  sulphate  and  disulphate  in 

alcohol 

Cinchonidine  in  alcohol 
Thebaine          "         " 
Glutin  "  water 


»-+   Increase  in  right  rotation 
*Isobutylamyl  oxide 
*Methylisoamyl  oxide 
*Diisoamyl  oxide 
*Amyl  acetate 
*Methyl  lactate 
*Tartaric  acid  esters 
Tartaric  acid  in  water 
Alkali  tartrates  in  water 
Glucuronic  acid  "      " 
Xylose  "      " 

N-propyl  dibutyryl  tartrate  in 
monobromethylidene  bromide 


A  change  in  the  direction  of  rotation  by  elevation  of  tem- 
perature, when  a  point  of  inactivity  is  passed  is  shown  in  the 
following  table  : 


Aspartic  acid  in  water. 

Malic  acid       "  " 

Tartaric  acid  "  "     , 

Invert  sugar    "  " 


On  the  last  four  substances  we  have  the  following  more 
complete  data  : 

Aspartic  Acid. — Aqueous  solutions  which  are  perfectly  free 
from  other  acids  as  well  as  from  alkalies,  exhibit  right  rotation 
at  the  ordinary  temperature.  But,  as  found  by  Ellen  Cook,1 
this  decreases  with  elevation  of  temperature,  and  passes  finally 
into  increasing  left  rotation,  the  point  of  inactivity  being 
passed  at  75°.  The  following  specific  rotations  for  white 
light,  \_a~\j  (converted  into  \_a~\D  by  multiplication  with  0.89), 
were  found  by  use  of  supersaturated  solutions.  The  values  of 
the  concentration,  c,  were  found  by  determination  of  the  density 
at  the  temperatures  at  which  the  rotations  were  observed. 

1  Ellen  P.  Cook :  Ber.  d.  chem.  Ges.,  30,  294. 


212 


SPECIFIC    ROTATION 


Specific  rotation. 

Solution. 
No. 

Amount. 

Temp. 

Specific 
gravity. 

Concentr. 

Observed. 

P 

t 

d( 

c 

*/ 

M/ 

E«3* 

I 

0.528 

20° 

I.OOI85 

0.531 

4-  0.103° 

+  4.900 

4-  4.36° 

II 

1.872 

32 

1.0043 

1.880 

+  0.320 

4-  4-25 

-f3-78 

II 

1.872 

40 

I.OOI5 

1.875 

4-  0-255 

+  3-40 

4-  3.°4 

II 

1.872 

50 

I.OOO4 

1.873 

4-  0.130 

4-  i.74 

-f  1-55 

II 

1.872 

60 

0.9917 

1.857 

4-  0.102 

4-  1-37 

4-   1.22 

II 

1.872 

75 

0.9821 

1.838 

o 

0 

O 

II 

1.872 

77 

0.9800 

1.835 

—  0.050 

-0.68 

—  0.61 

II 

1.872 

80 

0.9777 

1.830 

—  0.062 

-0.85 

—  0.76 

II 

1.872 

90 

0.9747 

1.825 

-0.155 

-  2.12 

-  1.86 

Malic  Acid  (common}. — Concentrated  solutions  show  right 
rotation  which  decreases  with  elevation  of  temperature;  dilute 
solutions  are  levorotatory  and  more  strongly,  the  higher  the 
temperature.  In  solutions  of  a  certain  strength  right  rotation 
appears  at  a  low  temperature,  and  left  rotation  at  a  high  tem- 
perature and  the  point  of  inactivity  changes  with  alterations 
in  the  percentage  amount,  p,  of  acid.  This  behavior,  which 
is  shown  by  neutral  sodium  malate  also,  can  be  seen  in  the 
following  observations  of  Th.  Thomsen:1 


Malic  acid . . . 


p                                          t  =  10°  t  =  20°  t  =  30° 

[53-75  !>]/>  =  +  2.52  [«]/>  =  4-  1-73  [»  =4-  0.94 

I  0.44                4-  1.31  +  0.54  -0.12 

I  28.67                4-  0.33  —  0.35  —  0.83 

[21.65                —0.44  —0.90  -1.43 


Sodium  malate .      42.75 


4-0.38 


-0.89 


—  2.04 


Tartaric  Acid. — In  examining  tartaric  acid  melted  with  a 
little  water  in  a  glass  vessel  with  parallel  walls,  Biot2  observed 
at  first  right  rotation  which,  with  falling  temperature,  decreased 
and  on  solidification  passed  into  left  rotation. 

The  right  rotation  characteristic  of  aqueous  solutions  of 
tartaric  acid  increases  with  heat  in  a  marked  degree,  as  appears 
from  the  following  observations  of  Krecke:3 

1  Th.  Thomsen:  Ber.  d.  chem.  Ges.,  15,  441. 

2  Biot:  Ann.  chim.  phys.,  [3],  59,  206,  §  11  (1860). 
*  Krecke:  Arch.  N£erland,  7,  97  (187*). 


DEPENDENCE  ON  TEMPERATURE 


213 


Amount  of  tartaric  acid  in  solution. 


Temp- 

40  Per  cent. 

20  Per  cent. 

10  Per  cent. 

0° 

|>]0  =+    5-53 

[>]*  =  +    8.66 

MD  =  -f    9-95 

10 

7-49 

9.96 

10.94 

20 

8.32 

H-57 

I2.25 

30 

9.62 

12.49 

13-93 

40 

11.03 

13-65 

15-68 

5° 

12.27 

15.01 

17.11 

60 

12.63 

16.18 

18.31 

70 

13-38 

17.16 

19.42 

80 

14.27 

18.40 

20.72 

90 

I5-9I 

19.99 

22.22 

ICO 

17.66 

21.48 

23-79 

Of  the  salts  of  tartaric  acid,  according  to  Krecke,  disodium 
and  sodium  potassium  tartrate  show  a  slight  increase,  but 
potassium  antimonyl  tartrate  a  decrease  in  rotation  by 
elevation  of  temperature. 

Invert  Sugar. — As  Tuchschmid1  found,  an  aqueous  solution 
with  17.21  grams  in  100  cc.  shows  a  diminution  of  its  left 
rotation  with  elevation  of  temperature,  according  to  the 
formula  :  [«]#  =  —  27.9  +  0.32  /.  Therefore,  the  rotation 
must  become  zero  at  87.2°,  to  pass  into  right  rotation  at  a  still 
higher  temperature.  In  agreement  with  this,  v.  Lippmann2 
found  the  point  of  inactivity  to  be  at  87.8°,  and  Casamajor3  at 
88°. 

If  alcohol  is  added  to  the  invert  sugar,  which  causes  a 
decrease  in  the  left  rotation,  the  change  in  direction  follows 
on  moderately  warming.  If,  for  example,  a  solution  of  19 
grams  of  cane-sugar  in  1 5  cc.  of  water  and  5  cc.  of  glacial 
acetic  acid  is  inverted  by  heating  in  the  water-bath,  and  diluted 
afterwards  to  100  cc.  with  absolute  alcohol,  the  liquid  which 
now  contains  20  grams  of  invert  sugar,  shows  the  following 
angles  of  rotation  : 

/  20°  30°  40°  50°  60 

a/j  for  2  dm.         —1.9°        —0.9°         -j-o.2°         +1-3°         —2.2° 
The    point    of  inactivity  is  therefore  found  to  be  about  38° 
(Landolt).4 
The  change  in  the  direction   of  rotation  may  be   explained 

1  Tuchschmid  :  J.  prakt.  Chem.,  [2],  a,  235  (1870). 
•  v.  I,ippmann  :  Ber.  d.  chem.  Ges.,  13,  1822  (1880). 

3  Casamajor  :  Wied.  Beib.,  (1879),  804. 

4  I^andolt  :  Ber.  d.  chem.  Ges.,  13,  2335  (1880). 


214 


SPECIFIC    ROTATION 


when  the  active  substance  consists  of  two  oppositely  rotating 
components  which  are  affected  to  different  extents  by  heat. 
This  is  the  case  with  invert  sugar.  As  first  shown  by 
Dubrunfaut,1  and  later  more  particularly  by  Honigand  Jesser,2 
the  rotating  power  of  levulose  decreases  rapidly  on  warming 
( aD  for  i  °  C.  about  0.67° ),  while  that  of  dextrose  is  but  slightly 
altered  ;  the  direction  of  rotation  of  the  latter  becomes  then 
gradually  apparent.  As  another  case,  Aignan3  has  shown 
that  a  mixture  of  left  turpentine  and  right  camphor  in  benzene 
may  change  its  direction  of  rotation  with  elevation  of  tem- 
perature, and  with  different  kinds  of  light  at  different  degrees. 
The  numbers  given  in  the  following  table  are  the  observed 
angles  of  rotation  in  a  2  dm.  tube  : 


Temperature. 

Red  light. 

Yellow  light. 

Green  light. 

-r-I3° 
33  to  38° 
5o  "  51 
61  "  62 
65  "  72 
81  "  90 

—  2.62 

-  1-53 
-0.83 

—  0-35 
+  0.18 
+  0.57 

-0.72 
—  0.40 
+  1-50 
+  I-98 
r  2.67 
+  3-°° 

+  2.40 
+  4-08 
-f  5-10 
i-  5-55 
•f  5-90 
+  6.72 

Finally,  it  is  of  interest  to  determine,  whether,  with  the  same 
substance,  elevation  of  temperature  and  increasing  dilution 
exert  like  changes  in  the  specific  rotation.  Thus  far,  but  few 
bodies  have  been  studied  in  both  directions,  and  with  several 
of  them,  the  alterations  observed  have  been  very  slight.  What 
has  been  found  is  tabulated  below. 

a.  Corresponding  Changes  in  the  specific  rotation  through 
increasing  dilution  or  elevation  of  temperature  occur  in  : 


—  0 

3  + 

" 

"*"""" 

1  Dubrunfaut :  Compt.  rend.,  43,  901  (1856). 

«  Honig  and  Jesser  :  Zeit.  Ver.  f.  Riibenzucker-Ind.,  (1888),  p.  1039. 

*  Aignan  :  Compt  rend.,  116,725,  (1893). 


ELECTROLYTIC  DISSOCIATION  IN  AQUEOUS  SOLUTIONS   215 

b.   Opposite  Effects  are  observed  in  the  following  cases: 


Increasing 
temperature. 
-   0°    + 

Increasing 
dilution. 
-0°    + 

Quinine  in  alcohol  •  •  .. 

«   m 

— 

— 

~ 

Ouinidine                   *  *             

Nicotine  in  water  or  alcohol  • 

Xvlose            " 

^/-Turpentine  jjj  alcohol  

/-            '*                           benzene,  acetic  acid  •• 

It  is  evident,  therefore,  that  increased  temperature  and 
dilution  have  sometimes  the  same  and  sometimes  the  opposite 
actions  and  that  no  definite  regularity  is  apparent  with  respect 
to  the  nature  of  the  substances  examined.  Those  cases  in 
which  an  explanation  of  this  behavior  is  in  any  degree  possible 
will  be  discussed  in  the  following  chapter. 

D.  Causes  of  the  Changes  in  Specific  Rotation. 
The  many  variations  which  are  exhibited  in  the  specific 
rotation  of  dissolved  substances  depend,  according  to  the 
nature  of  the  substances,  on  essentially  different  causes,  and 
all  changes  which  are  in  general  possible  with  solutions,  as 
electrolytic  dissociation,  formation  or  breaking  up  of  molecular 
aggregations,  hydrolysis  and  other  less  clearly  defined  effects 
may  come  into  play.  Besides  this  the  explanation  of  the 
phenomenon  is  made  difficult  by  the  fact  that  of  the  nature  of 
concentrated  solutions  almost  nothing  is  known.  Up  to  the 
present  time  the  following  data  have  been  accumulated  with 
reference  to  each  one  of  these  influences. 

61.  a.  Electrolytic  Dissociation  in  Aqueous  Solutions. — In  1873 
in  the  examination  of  a  number  of  neutral  salts  of  tartaric 
acid,  it  was  remarked  that  they  agreed  very  closely  with 
each  other  in  molecular  rotation,  from  which  it  was  clear 
that  differences  in  the  metals  combined  had  but  little  effect, 


216 


SPECIFIC    ROTATION 


and  this  not  in  any  relation  with  the  atomic  weight  (Landolt).1 
Oudemans*  appeared  to  find  in  solutions  of  cinchona  alkaloids 
in  different  dilute  acids  which  were  added  in  increasing  molec- 
ular weights,  a  difference  in  the  effects  of  these  additions,  but 
in  1879,  in  pursuing  further  investigations  with  quinamine, 
he  found  that  the  rotation  of  this  alkaloid  remains  almost 
unchanged  in  whatever  acid  it  is  dissolved.3  The  law  then 
stated,  "  the  specific  rotation  of  the  alkaloids  is  modified  in  the 
same  manner  by  different  acids,  provided  the  salts  formed  repre- 
sent the  same  condition  of  saturation  of  the  alkaloid  by  the  acid" 
was  later  confirmed  by  Oudemans4  in  the  study  of  quinidine- 
amine  and.  by  Tykociner5  with  brucine,  strychnine,  morphine 
and  codeine.  Finally,  Oudemaus6  showed  that  the  rule  holds 
good  for  the  active  acids  as  he  found  that  podocarpic  acid 
and  quinic  acid,  after  saturation  with  different  bases,  or  in  the 
form  of  dilute  salt  solutions,  retain  nearly  the  same  rotating 
powers. 

The  following  table  contains  some  of  the  results  referred  to, 
the  rotation  for  equal  molecular  weights  being  expressed  by 
(M)  for  salts  or  by  \_a]D  for  the  active  group: 


Tart  rates 
(Landolt). 

Quinates 
(Oudemans). 

Quinamine 
(Oude- 
mans). 

Strychnine 
(Tyko- 
ciner). 

i  mol.  of  acid  to  i  mol. 

of  base. 

In  100  cc. 

In  loo  cc. 

In  100  cc. 
7.69  grams 
tartaric  acid. 

IXJs 

of  the 
salt. 

In  loo  cc. 
2  .6  grams 
quinic  acid 

C;H1206. 

M/> 

of  the 
acid. 

Acids. 

1.56  grams 
base. 

MS 

of  the  base 

0.84  gram 
base. 

of  the  base. 

U2.C4H406 

(NH4)2 

63*0 

K.C7HU06 
Na 

—  48.8° 
48.9 

HC1 
HN03 

+  114-4° 
116.5 

-34.1° 
34-1 

Na, 

59-9 

NH4 

47-9   HC103 

116.1 

K2 

64.4 

Ba(C7Hu06)2 

46.6   H2S04 

116.4 

35-3    . 

Na.NH4 

61  *" 

Sr 

48.7   H3P04 

II7-3 

34-4 

K.NH4 

63-8 

Ca 

48.7    H3As04 

33-9 

K.Na 

62.3 

Mg 

47.8  CH202 

114.7 

34-0 

K.AsO 

58.8 

Zn 

51.0  C2H402 

116.2 

34-0 

K.C2H5 

64.6 

C2H204 

118.1 

33-1 

Bar/2C2H5 

63.0 



33  9 

Mg 

61.7 

Landolt :  Ber.  d.  chem.  Ges.,  6,  1077  (1873). 

Oudemans:  Ann.  Chem.  (Uebig),  182,  33,  58  (1876).    Arch.  Neerland,  10,  193. 
Oudemans:  Ann.  Chem.  (Uebig),  197,  48,  66    (1879).    Arch.  Neerland,    13,   155. 
See  further,  Rec.  trav.  Chim.  Pays-Bas,  i,  18  (1882). 

Oudemans:  Ann.  Chem. (Uebig),  aop,  38  (1881). 
Tykociner:  Rec.  trav.  Chim.  Pays-Bas.,  i,  144  (1882). 
Oudemans:  Ibid.,  4,  166  (1885). 


ELECTROLYTIC  DISSOCIATION  OF  AQUEOUS  SOLUTIONS   2 17 


In  investigations  on  the  effect  of  concentration  on  the  rota- 
tion of  salts  of  malic  and  camphoric  acids  it  was  shown 
further  that  their  molecular  relations,  which  are  very  different 
in  strong  solutions,  become  nearly  the  same  for  the  salts  of  the 
same  acid  as  the  dilution  increases.  Thus,  the  following 
molecular  rotations,  [-$/]£,  are  calculated  from  the  interpolation 
formulas  found  by  Schneider1  for  a  number  of  alkali  malates, 
the  water  present  amounting  to  about  40  to  90  per  cent: 


Water  in  100  parts  by  weight  of  solution. 

Mol. 
Wt 

40 

50 

60 

70 

80 

90 

Malic  acid  C4H6O5 

134 

-h3.io° 

+  1.89° 

+  0.68° 

-  0.59° 

-  1.71° 

-  2.91° 

Acid  salts 

UP  "R  O 

140 
151 
156 
I72 

i  So 

8f*\ 

—  10.16 

—11.28 
-  9-45 

8  72 

—11.77 

9Ro 

(NH  ^    " 

3.O2 
-7.72 
-0.08 

•44 
-8.15 
-2.65 

c   Q7 

-8.58 
5/1/1 

^jsn4; 
j^a          «      

.09 
—  10.02 
n  f\R 

K           " 

.U4 
-6.83 

7-°5 

—  7-77 

o.  /^ 

-  8.74 

4.92 

o-°/ 

Neutral  salts 
U,.C4H405  
(NH4),    "     
Na,          "     
K2            "     

146 

168 

178 

210 

+  5-90 
-7.29 

+  5-73 
-5-15 

—  0.26 
-8.13 

+  1.16 
-7-43 

-5-62 
-9.17 
-3-17 

-9-47 

—  10.09 
—10.35 
-  7.16 
—11.32 

—  13-77  —16.54 
—11.74  —13.27 
—10.93  —14-31 
—12.87  —14.26 

As  plainly  evident,  the  rotations  of  these  salts  in  concen- 
trated solutions  are  very  different  among  themselves,  and  even 
differ  in  sign,  but  with  increasing  dilution  they  become  more 
and  more  uniform.  Further,  it  is  seen  that  the  free  malic 
acid  shows  a  molecular  rotation  very  different  from  that  of  the 
malates. 

An  explanation  of  these  phenomena  was  first  given  by 
Hadrich2  in  1893,  and  based  on  the  theory  of  electrolytic  dis- 
sociation which  meanwhile  had  been  proposed  by  Arrhenius. 
Hadrich  makes  it  clear,  that  the  closely  agreeing  rotations 
which  the  different  salts  of  an  active  acid  or  base  exhibit  in 
equimolecular  solutions,  have  a  meaning  as  soon  as  it  is 
assumed  that  these  bodies,  as  electrolytes,  become  largely 

1  Schneider:  Ann.  Chem.  (I^iebig),  207,  257. 
-  Hadrich  :  Ztschr.  phys.  Chem.,  12,  476. 


218 


SPECIFIC    ROTATION 


dissociated  into  their  ions  on  sufficient  dilution,  because  then 
from  each  one  the  same  amount  of  active  acid  or  base  ions 
would  be  formed.  In  accordance  with  this  view  he  gave  to 
the  law  expressed  by  Oudemans,  this  extension  : 

The  rotating  power,  not  only  of  salts,  but  of  electrolytes  in 
general,  is,  in  approximately  completely  dissociated  solutions, 
independent  of  the  inactive  ion. 

A  confirmation  of  this  law  was  given  by  Hadrich  by  show- 
ing that  when  an  alkaloid  is  neutralized  by  different  acids,  and 
the  solutions  then  are  treated  with  increasing  amounts  of 
water,  ( i ) ,  the  molecular  rotations  become  constant  for  each 
salt  from  a  certain  concentration  on,  and,  (2),  that  the 
constant  values  for  the  molecular  rotations  of  the  different 
salts  agree  also  among  themselves,  as  shown  by  the  observations 
already  given.  In  the  following  table,  giving  some  of  these 
experiments,  the  numbers  show  the  molecular  rotations  of  the 
salts1  and  under  V  is  given  the  volume  of  water  in  liters,  in 
which  one  gram  equivalent  of  the  salt  is  dissolved  : 


Quinidine. 

Morphine. 

V 

Hydro- 
chloride. 

Nitrate.      Sulphate. 

Hydro- 
chloride. 

Nitrate. 

Sulphate. 

10 

...                ... 

-359° 

-36l0 

-357° 

20 

+  703° 

+  7030       +  702° 

364 

364 

364 

30 

712 

710               710 

365 

365 

365 

40 

717 

717               717 

37i 

368 

368 

60 

719 

723               719 

370 

370 

365 

80 

726 

726               726 

374 

369 

374 

120 

723 

723               723 

... 

160 

726 

726               726 

... 

... 

r/ 

Brucine. 

Strychnine. 

Hydro- 
chloride. 

Nitrate. 

Hydro- 
chloride. 

Nitrate. 

Sulphate. 

Amygdalate. 

10 

-I56° 

-I56° 

20 

141 

141 

-H3° 

-II4° 

-"3° 

-113° 

30 

138 

138 

114 

114 

114 

114 

40 

136 

136 

"3 

"3 

H3 

"3 

i  Instead  of  giving  the  molecular  rotations,  the  observed  angles  for  a  given  tube 
length  could  have  been  given,  as  the  solutions  contain  in  equal  volumes,  the  same 
amount  of  the  corresponding  alkaloid. 


ELECTROLYTIC  DISSOCIATION  IN  AQUEOUS  SOLUTIONS     2 19 

The  quinidine  and  morphine  salts  show  at  first  an  increase 
in  rotation  with  increasing  dilution  and  constant  values  are 
reached  when  the  dilution  of  the  first,  F,  is  brought  to  80  liters 
and  of  the  second  to  40  liters.  The  alkaloid  iron  possesses, 
therefore,  in  both  cases  a  greater  rotating  power  than  the  un- 
dissociated  salt  molecule.  With  brucine  the  opposite  is  the 
case;  and  the  strychnine  salts  appear  to  be  already  dissociated 
in  N/20  solution. 

The  agreement  in  molecular  rotation  in  dilute  aqueous  solu- 
tions has  been  observed  in  many  other  salts  containing  active 
bases  or  acids,  although  sometimes  with  considerable  varia- 
tions, the  cause  of  which  is  found  partly  in  insufficient  dilu- 
tion, and  partly  in  the  unequal  degrees  of  dissociation  for  the 
different  salts.  Further,  it  must  be  remembered  that  in  dilute 
solutions,  as  the  observed  angles  are  very  small,  experimental 
errors  exert  a  great  influence  on  the  final  result.  Observations 
have  been  made  on  the  following  substances:  Alkali  salts  of 
malic  acid  (Schneider),1  tartrates  of  different  metals  (von 
Sonnenthal,2  Pribram),3tartratesof  substituted  amines (Kanno- 
nikoff),4  alkali  salts  of  methyl  and  ethyl  tartaric  acid 
(Fayollat),5  salts  of  active  gly eerie  acid  (Frankland  and 
Appleyard),67  salts  of  quinic  acid  (Cerkez),8  alkali  salts  of 
active  valeric  acid  and  compounds  of  valeric  acid  with  inactive 
organic  bases  in  alcoholic  solutions  (Guye  and  Rossi),9  salts  of 
amyl  sulphuric  acid  and  salts  of  active  di-isoamyl  amine 
(Carrari  and  Gennari),10  conine  hydrochloride  and  hydro- 
bromide  (Zecchini),11  nicotine  salts  (Schwebel,12  Carrari),13 

Schneider:  Ann.  Chem.  (Liebig),  207,  257. 

v.  Sonnenthal:  Ztschr.  phys.  Chem.,  9,  656. 

Pribratn:  Wien.  Monatsh.,  14,  742. 

Kannonikoff :  J.  russ.  phys.-chem.  Ges.,  22,  36. 

Fayollat:  Compt.  rend.,  117,  632. 

Frankland  and  Appleyard:  J.  Chem.  Soc.,  63,  296. 

Frankland  and  Appleyard,  J.  Chem.  Soc.,  63,  311,  observed,  especially  with  the 
magnesium,  zinc  and  cadmium  salts  of  active  glyceric  acid,  variations  in  the  molecular 
rotation  from  that  found  with  the  alkali  salts,  and  in  consequence  of  this  were 
inclined  to  question  the  universality  of  the  Oudemans  rule. .  But  they  used  10  per  cent, 
solutions,  in  which  the  dissociation  was  incomplete,  and  which  likewise  for  the  differ- 
ent salts,  especially  those  of  the  dyad  metals,  might  be  very  unequal  in  extent. 

8  Cerkez:  Compt.  rend.,  117,  174. 

9  Guye  and  Rossi:  Bull.  Soc.  Chim.,  [3],  13,  465. 

10  Carrara  and  Gennari:  Ztschr.  phys.  Chem.,  17,  561. 

11  Zecchini:  Ztschr.  phys,  Chem.,  16,  246. 

12  Schwebel:  Ber.  d.  chem.  Ges.,  15,  2850. 

la  Carrara:  Ztschr.  phys.  Chem.,  14,  562,  16,  244. 


220 


SPECIFIC    ROTATION 


cinchonidine   salts    (Schuster),1   salts   of    d-    and    /-ruenthyl- 
amine  (Binz).2 

Of  observations  of  this  character,  those  which  Walden* 
made  on  tf-bromcamphorsulphonic  acid  and  its  salts,  may  be 
given  here  because  there  was  found  at  the  same  time  the  extent 
of  dissociation  by  means  of  determination  of  the  electrical  con- 
ductivity. The  solutions  contained  equivalent  amounts,  and 
c  indicates  the  number  of  grams  in  100  cc.  a  is  the  angle  of 
rotation  found  for  a  column  4  dm.  in  length  at  a  temperature 

Of  20.5V 


Dissociation 

aD 

1>_U 

L     ID 

in  per.  cent. 

Free-a-bromcamphor- 

14.952 

+  55-20° 

+   92.3° 

+  287° 

68.5 

sulphontc  acid.              1.0366          3.64 

87-7 

273 

92.7 

C10HuBrO.SO3H            0.5183          1.795 

86.6 

269 

94-4 

M=  311.                  0.2592          0.901 

86.9 

270 

95-5 

Potassium  salt. 

i  1633          3.644 

78.3 

273 

83-6 

C10H14BrO.S03K 

0.5817 

1-793 

77.1 

269 

87.2 

M  =  349. 

0.2908 

0.898 

77.2 

269 

90-3 

Thallium  salt. 

I.7I34 

3.633 

53-i 

273 

83.9 

C10H14BrO.S03Tl 

0.8567 

1.817 

52.9 

272 

87-3 

M=514. 

0.4283 

0.903 

52.7 

271 

90-5 

Zinc  salt. 

1.1417 

3.620 

79-3           272           71.5 

K(C10HMBrO.SO.)1.Zn] 

0.5709 

1-795 

78.6           269           77.2 

M  =  342.5. 

0.2854 

0.900 

78.8 

270 

81.8 

Barium  salt. 

1.2617 

3-630 

71.9 

272 

69.8 

H(C10HuBrO.S03)2.Ba) 

0.6309 

1.807 

71-6 

271 

74-8 

^=378.5 

0.3154 

0.895 

70.9 

269 

79-4 

As  can  be  seen,  the  molecular  rotations  of  all  these  bodies 
in  dilute  solution  approach  rapidly  the  constant  value  of  269 
to  270,  even  the  salts  of  dyad  metals,  although  these  are  less 
dissociated  than  the  alkali  metal  salts  or  the  free  acid.  In 

1  Schuster:  Wien.  Monatsh.,  14,  573. 

*  Binz:  Ztschr.  phys.  Chem.,  la,  734. 

3  Walden  :  Ztschr.  phys.  Chem.,  15,  196.  Kipping  and  Pope,  also,  (J.  Chem. 
Soc.,  63,  548)  have  investigated  some  salts  of  the  acid. 

*  The  original  paper  contains  observations  for  the  sodium  and  glucinum  salts. 


ELECTROLYTIC  DISSOCIATION  OF  AQUEOUS  SOLUTIONS  221 


general,  a  relatively  small  change  in  the  molecular  rotations  is 
observed,  corresponding  to  the  increasing  degree  of  dis- 
sociation. 

Free  acids  which  behave  as  good  electrolytes,  must  show,  in 
sufficiently  dilute  solution,  the  same  molecular  rotation  as  the 
neutral  salts,  since  the  concentration  of  the  active  ions  is 
finally  the  same.  This  is  illustrated  with  tf-bromcamphor- 
sulphonic  acid  described  above.  If,  on  the  other  hand,  the 
acid  is  a  poor  electrolyte  and  at  the  same  time  is  dibasic,  as 
tartaric  acid  or  malic  acid,  then  in  consequence  of  the  lower 
degree  of  dissociation  and  also  of  the  formation  of  different 
active  ions  (for  example,  C4H5O5  and  C4H4O5  from  C4H6O5) 
the  observed  molecular  rotation  will  depart  widely  from  that  of 
the  neutral  salts.1  The  acid  salts  also  may  not  agree  with 
these,  because  here  different  conditions  of  dissociation  obtain. 
These  differences  are  shown  in  the  following  table  which  em- 
braces observations  of  Schneider*  on  malic  acid  and  malates  in 
5  per  cent,  solutions,  and  of  Landolt3  on  tartaric  acid  and 
tartrates: 


Malic  acid. 

IM\D 

Tartaric  acid. 

[*]* 

Free  acids. 

C4H605 

-  3.2° 

C4H606 

+  21.1° 

Li.C4H505 

—  11.9 

Li.C4H506 

+.42.8 

Acid  salts. 

Na 
K 

10.5 

10.2 

Na 
K 

4L2 
42.5 

NH4      " 

10.1             NH4      "                     42.8 

U2C4H405 

-17.7 

Li.2C4H406 

+  58.1 

Neutral 

Naj 

16.0 

Na2       "                      59-9 

salts. 

K2         " 

14.8     I        K2 

64.4 

(NH4)2" 

14.1 

(NH4)2'< 

63.0 

1  From  the  measurements  of  Ostwald  (Ztschr.  phys.  Chem.,  3,  371)  on  the  elec- 
trical conductivity  of  tartaric  acid,  it  follows  that  this  acid  in  a  concentration  of  0.3 
gram  per  liter  is  only  about  one-half  dissociated,  while  the  extent  of  dissociation  for 
the  neutral  tartrates  can  be  taken  as  above  95  per  cent. 

2  Schneider:  Ann.  Chem.  (Liebig),  207,  257.    The  numbers  given  are  calculated 
from  the  interpolation  formula  given  for  q  =  95. 

3  lyandolt:  Ber.  d.  chem.  Ges.,  16,  1076.    The  concentrations  employed  were  equiva. 
lent  to  7.69  grams  of  tartaric  acid  in  100  cc.  for  the  neutral  tartrates.    Weaker  solutions 
were  used  for  the  acid  salts. 


222 


SPECIFIC    ROTATION 


The  acid  salts  in  respect  to  their  rotation  stand  between  the 
free  acids  and  the  neutral  salts.  From  them,  for  example 
from  the  acid  malates,  at  first,  in  the  main,  the  ion  C4H5O5 
separates,  which  with  greater  dilution  passes  into  C4H4O5. 
Finally  the  same  molecular  rotation  should  be  expected  as 
with  the  neutral  salts  but  sufficient  observations  are  lacking  to 
show  this.1 

With  the  salts  of  very  weak  bases  and  acids  besides  the 
electrolytic,  hydrolytic  dissociation  may  also  take  place,  by 
which  the  number  of  atomic  aggregations  in  the  liquid  is  still 
further  increased.  Such  complicated  changes  appear  to-  take 
place  with  the  di-hydrochlorides  of  the  cinchona  alkaloids, 
inasmuch  as  these  do  not,  like  the  monohydrochlorides,  give  a 
constant  end  value  for  the  molecular  rotation  by  increasing 
dilution.  The  following  numbers  for  \_M~\D  were  found  by 
Hadrich,2  in  which  i  gram-molecule  of  substance  was  con- 
tained in  V  liters: 


V 

10 

20 

40 

80 

160 

3» 

Cinchonidine- 

dihydrochloride  

-    525° 

-   521° 

-  516° 

-  504° 

-     465° 

monohydrochloride 

-    356 

-  381 

-   400 

-   402 

Quinidine- 

dihydrochloride-  .  .  . 

-+-  IOT1 

+  1028 

-1043 

-h  1049 

4-  1123 

+  1225 

monohydrochloride 

+  703 

+  717 

+    726 

+  726 

The  great  differences  between  the  mono- and  dihydrochlorides 
are  without  doubt  caused  not  only  by  differences  in  the  nature 
of  the  electrolytic  dissociation  but  also,  especially  with  quini- 
dine,  by  the  existence  of  other  kinds  of  dissociation. 

If  the  degree  of  dissociation  of  an  active  body  be  diminished 
by  adding  to  the  solution  other  substances  which  also  behave 
as  electrolytes,  a  change  in  the  rotating  power  follows.  Acids 
must  produce  such  an  action  and  in  fact  it  has  been  found  that 
the  specific  rotation  of  tartaric  acid  experiences  a  decrease 
when  the  aqueous  solution  is  treated  with  hydrochloric,  nitric, 
sulphuric,  or  acetic  acid.  Equivalent  amounts  of  these  acids 

1  The  interpolation  formulas  of  Schneider  gave  for  q  =  too  very  great  differences 
between  the  acid  and  neutral  malates. 

2  Hadrich:  Ztschr.  phys.  Chem.,  la,  491. 


HYDROLYTIC    DISSOCIATION 


223 


exert  influences  in  different  degrees  (Landolt).1  Oudemans2 
observed  the  same  phenomenon  on  treating  di-acid  alkaloids 
with  i,  2,  3,  ...,  molecules  of  different  acids.  At  first  an 
increase  in  the  specific  rotation  follows  and  continues  to  a 
maximum,  which  appears  when  somewhat  more  acid  is  present 
than  is  required  for  formation  of  the  neutral  salt,  and  then  a 
continuous  decrease  takes  place.  Of  numerous  observations 
the  following  may  be  given: 

Cinchonine. — In  100  cc.  of  solution  5  mg.  molecules  of 
alkaloid  -f-  n  mg-  molecules  of  acid.  The  maximum  values 
are  shown  by  *  : 


Mol.  acid 
to  i  mol.base. 

Hydrochloric  acid. 

Nitric  acid. 

Formic  acid. 

I 

[>]2  =  -f  201.0° 

+  I9I.70 

.... 

2 

2-54-1 

253.4 

242.2° 

4 

259.0* 

257.3 

243-9 

3 

258.7 

257-8* 

245-6 

4 

257-7 

254.6 

250.7 

6 

253-3 

252.1 

256.6 

10 

252.1 

251.8 

257.8 

20 

246.0 



258.9* 

45 

.... 

.... 

257-9 

92 





254.0 

The  increase  in  the  rotation  at  the  beginning  may  possibly 
be  explained  by  the  assumption  of  hydrolytic  dissociation  on 
addition  of  small  amounts  of  acid.  The  behavior  of  the  acids 
depending  on  their  different  degrees  of  affinity  is  also  evident, 
inasmuch  as  to  reach  the  maximum  rotation  unequal  amounts, 
of  hydrochloric  acid,  2^  mols.,of  formic  acid,  on  the  other 
hand,  20  mols. ,  are  required. 

Alkalies  act  in  the  same  manner  as  acids.  From  observa- 
tions of  Th.  Thomsen3  it  appears  that  the  specific  rotation  of 
neutral  sodium  tartrate  undergoes  a  progressive  decrease  on 
addition  of  increasing  amounts  of  sodium  hydroxide,  while 
by  addition  of  water,  on  the  other  hand,  it  increases. 

In   the   same  way  the  changes   in  specific  rotation  which 

1  I^andolt:  Ber.  d.  chem.  Ges.,  13,  2331. 

2  Oudemans:  Rec.  trav.  Chim.  Pays-Bas,  i,  28. 

3  Th.  Thomsen:  J.  prakt.  Chem.  [2],  35,  145;  also  Aignan:  Compt.  rend.,  na,  1009. 


224 


SPECIFIC    ROTATION 


follow  by  addition  of  salts  (§  70)  depend  largely  on  alterations 
in  electrolytic  dissociation. 

If,  finally,  active  electrolytes  are  dissolved  in  liquids  which 
possess  a  smaller  dissociating  power  than  water,  the  specific 
rotation  in  comparison  with  that  in  the  latter  will  assume  a 
new  value,  which  may  be  larger  or  smaller  according  as  the 
active  ion  possesses  a  greater  or  less  rotating  power  than  the 
undissociated  molecule.  The  same  phenomenon  must  be 
observed  when  such  a  liquid,  for  example  alcohol  or  acetone, 
is  added  to  an  aqueous  solution  of  the  body.  Among  the 
many  observations  on  this  point,  the  following  by  Walden1 
may  be  quoted  in  which  the  extent  of  dissociation  has  been 
calculated  from  the  electric  conductivity: 


Substance. 

Solvent. 

c 

ws> 

Dissociation. 
Per  cent. 

Water 

\      271° 

«-Brom- 
camphor 

7  parts  water     1 
~f~  93  Parts  acetone  * 
Water  

1.0366 
o  ^187 

T  *'j 
343 
260 

92.7 
5-9 

sulphonic  acid 

3.5  parts  water     "I  ^ 
+  96.5  parts  acetone  I 

0.5183 

^uy 
326 

94-4 
4.1 

I  2617 

272 

60  8 

a-Brom- 
camphor 

7  parts  water      ) 
4-  93  parts  acetone  *  ' 
Water  

1.2617 
o  6100 

*/• 

328 
271 

8.1 

7/1   8 

sulphonate 

3.5  parts  water     1 
-4-96.5  parts  acetone  f 

U>UO'J7 
0.6309 

*/*• 
301 

74.0 
5-0 

Oudemans2  found  that  some  of  the  salts  of  the  cinchona 
alkaloids  rotate  in  alcoholic  solution  more  strongly  than  in 
aqueous,  others  less  strongly. 

In  general  many  of  the  variations  shown  in  the  specific  rota- 
tion of  bodies  dissolved  in  different  solvents  depend  on  differ- 
ences in  the  extent  of  electrolytic  dissociation,  provided  dilute 
solutions  are  considered. 

1  Walden:  Ztschr.  phys.  Chem.,  15,  205. 

2  Oudemans:  Rec.  trav.  Chim.  Pays-Bas,  i,  18. 


DISSOCIATION   OF   SALTS  225 

Dissociation  of  Salts  with  Active  Anion  and  Kation. — For 
such  bodies  the  experiments  of  Walden1  have  shown,  as  was  to 
be  expected,  that  the  rotations  in  dilute  solutions  are  equal  to 
the  sum  of  the  rotations  for  the  ions.  For  flf-bromcamphorsul- 
phonate  of  morphine,  C10HuBrO.HSO3.C17H19NO3,  dissolved  in 
water,  he  found: 

C  =  1.9867  \M]n  =  —   100° 

c  =  0.9933      \M]D  =  —  101° 

For  the  morphine  ion  we  have,  according  to  the  experiments 
of  Hadrich,  cited  above,  the  values  —  365  to  374,  in  the  mean 
—  371  for  \M\D.  For  the  ion  of  bromcamphor  sulphonic 
acid  we  have  \_M~\D  =  -f  269  to  -f-  273,  in  the  mean  4-271. 
Hence  as  molecular  rotation  of  the  dissociated  salt  we  must 
have 

\M\D  =    -  371  +  271  =    -  100°, 
which  agrees  with  the  above  observation. 

This  behavior  is  shown  also  with  quinidine  tf-bromcamphor 
sulphonate,  where  both  ions  are  right  rotating. 

Behavior  of  Boryl,  Arsenyl  and  Antimonyl  Tartrates. — These 
compounds  which  are  formed  by.  heating  acid  tartrates  with 
boric  acid,  arsenious  oxide  and  antimonious  oxide  show  marked 
deviations  in  their  rotating  power  from  the  ordinary  neutral 
tartrates.  With  the  latter  the  rotation  increases  with  increas- 
ing dilution  and  reaches  a  constant  value  wrhich  corresponds  to 
the  completely  separated  ion,  C4H4O6.  Thus  from  the  formula 
of  Th.  Thomsen2  for  ^/-sodium  tartrate, 

[M^D  =  60.56  —  0.04647^  —  o.  002216  p2, 
the  following  numbers  may  be  calculated  for  solutions  which 
contain  F  liters  of  water  for   i  gram-mol.   of  salt   (or  in  100 
parts  of  solution  p  grams  of   salt).     These  values  for   [M~\D 
change  but  little. 

V  i  2    ~  4  8  16  32 

p—  0.1625         0.0884        0.0462         0.0238        0.0120         0.0060 

[M]/>  —  —  59.22         59.98         60.30         60.45         6o-5o         60.53 
The  same  end  value,  as  remarked  before,  is  found  with  the 
other  neutral  tartrates. 

On  the  other  hand  Hadrich  found  for  certain  alkali  boryl 

1  Walden:  Ztschr.  phys.  Chem.,  15,  206. 
-  Thomsen:  Jour,  prakt.  Chem.  [2],  34,  80. 

15 


226 


SPECIFIC    ROTATION 


tartrates   the  following  molecular  rotations,  when  the  same 
dilutions  were  employed  (i  gram-mol.  of  salt  in  V liters).1 


V. 

K(BO)C4H406. 

Na(BO)C4H4O6. 

NH4(BO)C4H400. 

I 

+  143° 

+  152° 

+  H80 

2 

134 

133 

136 

4 

121 

122 

121 

8 

106 

107 

107 

16 

88 

89 

89 

32 

74 

74 

74 

We  have  here  to  begin  writh  a  much  larger  molecular  rota- 
tion than  with  the  simple  tartrates,  and  this  is  explained  by 
the  circumstance  that  the  separated  ion  is  not  C4H4O6,  but 
C4H4O6.BO.  Secondly,  the  rotation  decreases  rapidly  with 
increasing  dilution  and  for  V  -  16  is  not  yet  approaching 
constancy.  As  appears  from  the  investigations  of  Magnanini2 
on  the  conductivity  of  solutions  of  boro-tartaric  acid  this  may 
be  referred  to  gradual  hydrolysis  taking  place  at  the  same  time 
which  brings  about  a  decomposition  of  the  complex  ion, 
C4H4O6.BO.  Finally  the  ion  C4H4O6,  with  \_M^D  =  60.5,  must 
be  present. 

The  arsenyl  tartrates  act  in  the  same  way.  Hadrich  found 
for  [AT\D: 


V 

Na(AsO)C4H406. 

NH4(AsO)C4H4Oti. 

2 

4-  224° 

-f  230° 

4 

185 

186 

8 

131 

132 

16 

79 

80 

32 

63 

63 

With  these  compounds  in  the  most  dilute  solution  the  rota- 
tion of  the  tartar ic  acid  ion  (58  to  63  as  already  given)  has 
been  reached. 

Other  phenomena  are  shown  by  potassium  antimonyl  tartrate 
(tartar  emetic).  Here  we  have  very  strong  rotation  which 
scarcely  decreases  by  dilution.  For  the  formula  KSbOC4H4Oa, 
Hadrich3  found  these  numbers: 

1  Hadrich:  Ztschr.  phys.  Chem.,  13,  494. 

*  Magnanini:  Ibid.,  6,  67. 

*  Hadrich:  loc.  cit. 


DISSOCIATION   OF   MOLECULAR    AGGREGATIONS 


227 


1=  2.35  dm. 


4 
13.70 

548 


i6  32  64 

6.85  3.42  1.70          0.85° 

548         546         544          544 
Mol.  conductivity,  M         ...         70.58      79.45       87.63       94.20 

Some  hydrolysis  takes  place  here  as  shown  by  Hadrich  from 
the  manner  of  change  in  the  conductivity,  but  only  to  a  slight 
extent.  An  explanation  of  the  slight  change  in  the  molecular 
rotations  is  still  lacking. 

62.  b.  Formation  or  Decomposition  of  Molecular  Aggregations  of 
Simple  Structure. — As  is  well  known  molecular  weight  deter- 
minations by  the  freezing-  or  boiling-point  method  have  shown 
that  many  substances,  liquid  as  well  as  solid,  when  dissolved 
in  certain  liquids  appear  as  single  molecules,  while  in  others 
they  exist  as  double  molecules  (for  example,  acetic  acid  in 
ether  =  C2H4O,,  in  benzene  =  (C2H4O2)2,  etc.).  Experiments 
have  accordingly  been  made  to  determine  whether  the  influence 
which  several  solvents,  or  their  concentrations,  exert  on  the 
specific  rotations  of  many  substances  corresponds  to  a  change 
in  the  molecular  weight  of  the  latter.  On  this  subject  we 
have,  mainly,  the  following  investigations: 

Freundler1  dissolved  a  number  of  tetra-substituted  tartaric 
acid  esters,  the  rotations  of  which  in  pure  condition  were 
known,  in  different  liquids  (c  =  5  to  6)  and  determined  the 
specific  rotation  and  the  molecular  weight.  He  believes  the 
following  laws  obtain  for  these  bodies: 

i .  In  solvents  which  change  the  rotation  of  the  esters  but 
little  or  not  at  all,  the  latter  show  the  normal  molecular  weight. 
For  example: 


Molecular  weight. 

Spec.  rot.   [<*]  D. 

Solvent. 

Active  substance. 

From 

Obser- 

In solu- 

Without 

- 

formula. 

vation. 

tion. 

solvent. 

- 

Propyl   dipropionyl   tartrate     346          342 

+     5-4° 

+    5-5° 

Ethy- 

dibutyryl 

374 

363 

+    5-5 

+    5-2 

lene 

"        divaleryl              " 

402          389 

+    3-6 

+    3-6 

bromide        "       dicaproyl 

430 

424 

-h    2.4 

+      2.2 

Methyl  divaleryl 

346 

348 

-15-6 

—  15-9 

Benzene           Isobutylamyl  oxide 

144 

I4T 

+    1.4 

+    1-3 

1  Freundler:  Ann.  chim.  phys.,  [7],  4,  256  (1895). 


228 


SPECIFIC    ROTATION. 


2.  In  solvents  which  bring  about  a  marked  change  in  the 
original  specific  rotation  of  the  esters,  anomalous  numbers  are 
found  in  the  cryoscopic  molecular  weight  determinations. 
For  example  : 


Solvent. 

Active  substance. 

Molecular  weight. 

Spec.  rot.   \_Ot\D. 

From 
the 
formula. 

Obser- 
vation. 

In  solu- 
tion 
c  =  5  to  6 

Without 
solvent. 

Benzene 

Propyl  diacetyl  tartrate 

318 

277 

4-    1.2° 

+  13.4* 

« 

"       dipropionyl    " 

346 

295 

-    3-4 

+    5-6 

« 

"       dibutyryl        " 

374 

304 

1.4 

+    5-2 

«i 

11       divaleryl         "                 402          324 

—      2.2 

+    3-3 

11 

"       dicaproyl        " 

430 

345 

-     4-3 

4-      2.2 

Nitro- 

benzene 

Isobutyl  diacetyl         " 

346 

3i8 

-f-    12.0 

-f    17.0 

Nitro- 

benzene 

Ethyl  dicaproyl          " 

402 

376 

-    5-i 

-    3-i 

Acetic  acid 

Isobutyl  dipropionyl  " 

374 

287 

-f  20.2 

-f-    IO.2 

Ethylene 

bromide 

Ethyl  diphenylacetyl  tartrate 

442 

394 

+    19.2 

+    15-2 

Ethylene  - 

bromide    Propyl      "           "            " 

470 

406 

+   23.3 

+  20.9 

Benzene 

«            (i           «             « 

470 

413 

4-  15-7 

+  20.9 

Nitro- 

benzene 

i<            «           >  i             « 

470 

378 

-f  14.6 

+   20.9 

Acetic  acid 

i  <            <  <           <  <             K 

470 

377 

+  27.2 

+  20.9 

In  all  these  cases,  the  specific  rotation  of  the  dissolved  sub- 
stance is  markedly  different  from  that  of  the  original  solvent- 
free  body,  being  sometimes  higher,  sometimes  lower,  and 
sometimes  showing  a  change  in  direction.  The  molecular 
weights,  as  determined,  are  all  below  the  normal,  which 
probably  depends  on  dissociation  of  the  compounds. 

Freundler  also  found  substances  whose  molecular  weights  in 
solution  are  much  larger  than  the  formula  weights  and  which 
show  marked  changes  in  rotating  power.  The  explanation 
here  may  be  found  in  polymerization.  The  following  simple 
esters  of  </-tartaric  acid  behave  in  this  manner: 


DISSOCIATION   OF   MOLECULAR   AGGREGATIONS 


229 


Solvent. 

Active  substance. 

Molecular  weight 

Spec,  rotation   [«]/> 

From  the 
formula. 

Observa- 
tion. 

In 
solution. 

Without 
solvent. 

+     2.14 

Benzene 

Methyl  tartrate          178 

411 

-     8.8 

Benzene 

Propyl         "                234 

306 

-f  20.1 

+  12.44 

Ethyl  bromide                                          234 

326 

-    0.6 

+  12.44 

The  rotation  and  molecular  weight  of  nicotine  in  different 
solvents  has  been  investigated  by  Hem,1  and  with  concentra- 
tions at  which  the  boiling-point  method  yields  reliable  results. 
It  was  found  that  by  diminishing  the  percentage  amount  of 
nicotine,  /,  the  specific  rotation  was  also  diminished,  although 
writh  several  liquids,  as  ether,  acetone,  and  benzene,  in  very 
small  degree,  and  somewhat  more  with  ethyl  and  propyl 
alcohol.  The  molecular  weights  appear  from  the  observations 
to  undergo  a  slight  decrease  with  decrease  in  /,  but  the  values 
are  all  very  near  the  normal  number.  The  following  are  the 
results  obtained: 

Pure  nicotine:  a*%  =  —  164.0°.     Molecular  weight  —  162. 


Solvent. 

Decrease  in 
percentage  amount 
of  nicotine. 

Corresponding  decrease 
in  specific  rotation. 

Ms 

Molecular 
weight 
found. 

Ethyl  alcohol  . 
Propyl  alcohol 
T^tVipr 

From  11.4  to  1.7 
"     13.4  "  2.0 

From  —  141.1°  to  139.0° 
-  147.2     "  144.6 
<«            169  i     "  ifii  8 

167  to  164 
156  "  152 

iv-y     4-u 

*  '       12  O    *'   2  'Z 

"          163  3    "  162  6 

192        177 

188  "  172 

"       IA.A    "   7.S 

"       Tfi7  8       "   fftl  A 

T7C    "    T72 

Solutions  of  nicotine  in  water  show,  on  the  other  hand,  a 
different  behavior.  As  pointed  out  in  §  56  the  specific  rotation 
changes  within  the  limits  [or]"  =  —  76.84  to  77.59  when  the 
percentage  strength  sinks  from/  =  15.59  to  1.06,  with  a  mini- 
mum at/  =  9.  The  molecular  weight,  found  cryoscopically, 
shows  however,  according  to  the  observations  in  §  56,  a  very 
strong  decrease;  it  has  for/  =  13.74  the  value  275,  which 
gradually  sinks  to  the  normal,  162,  when/  is  less  than  2  per 

1  J.  Hein:  Ueber  das  specif.  Drehungsvermogen  und  das  Moleculargewicht  des 
Nicotins  inLosungen,  Inaug.  Diss.,  Berlin  (1896). 


230 


SPECIFIC    ROTATION 


cent.     In  this  case  the  great  change  in  molecular  weight  has 
no  influence  on  the  rotating  power  of  the  substance. 

Rotation  and  molecular  weight  in  solutions  of  different  con- 
centrations have  been  further  investigated  by  Frankland  and 
Pickard1  with  the  following  substances: 


Solvent. 

Decrease  in 
per  centage 
amount  of 
active  sub- 
stance. 

Corresponding  change 
in  specific  rotation, 

[«U 

Molecular  weight 
found  cryoscopically. 

rf-Dibenzoylgly cerate  of  methyl  [a]  XJ  =  -f  26.9  ;  M  ==  328. 

Between  299  and  322 


Benzene 

34.  i  to  3.0    Inc. 

from  +40.7  to  45.7 

Nitro- 

benzene 

28.1  "  2.4  j  Dec. 

"     4-22.0  "  19.8 

Ethylene- 

bromide 

22.3  "3.3 

11 

"     4-  21.7  "   19.2 

Acetic  acid 

18.6  "  1.7 

Inc. 

"     +  32.4  "  34-3 

305  "   341 


322    '      359 

305    "     34i 


/-Diacetylglycerate  of  ethyl  [a]  'J  =  —  16.31  ;  M=  218. 


Benzene 
Acetic  acid 

29.8  to  5.3 
25-0  "  3-4 

Inc.  from  — 
«i        « 

i4.8to  17.2 
19.4  "  28.7 

Dec.  from  216  to  209 
"     194  "  136 

With  the  first  ester,  no  definite  change  in  the  molecular 
weight,  corresponding  to  increase  or  decrease  in  the  specific 
rotation  with  diminished  concentration,  is  noticed ;  for  the 
molecular  weight,  irregularly  varying  numbers  were  found, 
which  are  not  very  far  from  the  normal  formula  weight. 

The  diacetylglycerate  of  ethyl  dissolved  in  benzene  shows 
an  increase  in  rotation,  but  a  decrease  in  the  corresponding 
nearly  normal  molecular  weight.  In  acetic  acid,  the  rotation 
increases  likewise  and  the  molecular  weight  decreases,  but  the 
latter  shows  values  which  are  much  smaller  than  the  normal, 
so  that  dissociation  appears  to  have  taken  place  here. 

With  the  ethyl  ester  of  /-mandelic  acid,  the  following  values 
were  found  by  Walden*  for  the  specific  rotation  and  molecular 
weight,  the  latter  being  determined  by  elevation  of  the  boiling- 
point  : 

1  P.  Frankland  and  Pickard:  J.  Chem.  Soc.,  69,  123. 

2  Walden  :  Ztschr.  phys.  Chem.,  17,  705. 


DISSOCIATION   OF    MOLECULAR    AGGREGATIONS  23! 

Pure  ester  (superfused)  [a]D  =    -  123.1°;  M=  180. 


Solvent.  c 


Molecular  weight  found. 


175-4  (4-2i  subst.  in  100  pts.  solution) 
I.  ID    —    07.1 

Carbon  disulphide      5.00   -  180.0  ,,         „  M 

"  2.50   —  iSo.o 

The  original  specific  rotation  of  the  ester  experiences,  there- 
fore, in  acetone  a  marked  decrease,  but  in  disulphide  of  carbon, 
on  the  other  hand,  an  increase,  while  the  molecular  weight  is 
normal  in  both  solutions. 

Finally,  o'-mononitrocamphor  dissolved  in  carbon  disulphide 
shows  a  strongly  decreasing  rotation  with  increase  in  concen- 
tration, but  in  alcohol  only  a  slight  change.  In  both  solvents 
the  substance  possesses  the  normal  molecular  weight 
(Pescetta).1 

According  to  the  above  observations  the  following  phe- 
nomena, in  general,  have  been  noticed: 

1.  A  change   in    the   rotation,   with  the  molecular  weight 
remaining   normal    (ethyl    mandelate,     tf-mononitrocamphor, 
nicotine  in  ethyl  and  propyl  alcohol). 

2.  A   change  in   the  molecular  weight  while  the  rotation 
remains  constant  (nicotine  in  water) .     In  these  two  cases  there 
can,  naturally,  be  no  relation  between  the  constants. 

3.  Simultaneous  changes  in  rotation  and  molecular  weight. 
If  here  the  molecular  weight  in  solution  is  much  greater  than 
the  normal,  the  cause  of  the  modified  rotation  is  probably  found 
in  a  polymerization  of  the  molecule  ( simple  tartrate  esters).     If 
the  molecular  weight  is  found  to  be  smaller  than  the  normal, 
the  change  in  rotation  is  probably  due  to  beginning  dissocia- 
tion (diacetyl  glycerate  of  ethyl  in  acetic  acid). 

Whether  or  not  the  variations  from  the  original  specific 
rotation  which  were  found  in  the  tetra-substituted  esters  of 
tartaric  acid,  investigated  by  Freundler,  when  they  were  dis- 
solved in  different  solvents,  have  any  connection  with  the 
decrease  in  molecular  weight  observed  at  the  same  time,  can 
not  be  shown  with  certainty. 

1  Pescetta:  Gazz.  chim.  ital.,  25,  II,  418. 


232  SPECIFIC    ROTATION 

63.  c.  Presence  of  Complex  Polymerized  Molecules  (Crystal  Mole- 
cules) in  the  Solution. — While  it  is  not  clear  how  by  association 
of  two  or  only  a  few  molecules  the  original  rotation  should  be 
altered,  some  action  should  follow,  on  the  other  hand,  when  a 
large  number  of  active  molecules  unite  to  produce  a  crystal 
structure,  which  in  turn  possesses  asymmetric  form.  It  has 
already  been  shown,  in  §  7,  that  those  bodies  which  are  active 
in  dissolved  and  in  crystalline  condition  possess,  in  the  latter 
form,  a  rotating  power  which  is  due  to  the  combined  activity  of 
the  single  molecules  and  the  crystal  molecules.  If  the  assump- 
tion may  be  made  that  in  concentrated  solutions,  at  least,  of 
solid  active  substances,  such  complex  aggregations  are  present, 
which  by  continued  dilution  gradually  break  down  into  normal 
molecules,  then  the  corresponding  changes  in  the  rotation  may 
be  explained. 

The  possibility  of  the  occurrence  of  such  crystal  molecules 
in  solutions  has  been  frequently  affirmed  by  Groth,1  Fock,2 
Bell,3  Wyrouboff4  and  others,  but  experimental  proof  is  thus  far 
wholly  lacking.  It  is,  however,  possible  that  the  following 
phenomena  observed  in  aqueous  solutions  of  malic  and  tartaric 
acids  may  be  ascribed  to  this  cause. 

Ordinary  malic  acid  exhibits  left  rotation  in  dilute  aqueous 
solutions,  and  this  grows  less  with  increasing  concentration, 
passes  through  a  point  of  inactivity,  and  finally  turns  to  increas- 
ing right  rotation  (§  57).  The  same  phenomenon  is  noticed  on 
lowering  the  temperature  (§  60).  With  ^/-tartaric  acid,  on 
the  other  hand,  the  rotation  changes  from  right  to  left  gradu- 
ally as  the  concentration  becomes  very  great  (§  46).  For  each 
spectrum  color  the  point  of  inactivity  appears  at  a  certain  and 
distinct  concentration  (§  46). 

These  marked  variations  in  the  rotation  can  not  be  explained, 
as  Nasini  and  Gennari5  especially  have  pointed  out,  by  ( i ) 
electrolytic  dissociation,  because  this  with  malic  acid  and  tar- 
taric acid  is  noticeable  only  in  very  dilute  solutions,  where  an 
accurate  observation  of  the  rotation  could  no  longer  be  made  ; 

Groth:  "  Physikal.  Krystallog.,"  Ill  ed.  (1895),  p  268. 

Fock:  "  Einleitung  in  die  cheniische  Krystallographie  "  (1888),  p.  19. 

Louis  Bell:  Silliman's  Jour.  [3],  7,  120. 

Wyrouboff:  Compt.  rend.,  115,  832;  Bull.  Soc.  Chim.,  [3],  9,  214. 

Nasini  and  Gennari:  Ztschr.  phys.  Chem.,  19,  113 


PRESENCE   OF    COMPLEX    POLYMERIZED   MOLECULES     233 

(2)  by  simple  polymerization,  as  cryoscopic  observations 
with  malic  acid  in  concentrations  9  and  24.5  have  shown  the 
normal  molecular  weight  ;  (3)  by  formation  of  hydrates  of 
variable  composition;  for  the  reasons  given  in  §  64  these  are 
in  general  not  possible. 

The  phenomenon  may  be  understood,  however,  if  wre  assume 
that  the  left-rotating  single  molecules  of  malic  acid  with 
increasing  concentration  gradually  combine  to  form  right- 
rotating  aggregations,  and  the  right-rotating  tartaric  acid 
molecules  to  form  left-rotating  groups.  Accordingly,  finally, 
in  anhydrous  condition,  /-malic  acid  should  exhibit  right 
rotation  and  d- tartaric  acid  left  rotation.  With  the  first  acid 
this  has  not  been  shown  experimentally,1  but  in  the  case  of 
tartaric  acid  it  has  been,  as  already  mentioned  in  §  46.  That 
this  condition  can  actually  obtain  when  solid  crystalline  par- 
ticles separate  is  shown  in  the  case  of  rubidium  tartrate,  which, 
as  explained  in  §  7,  possesses  right  rotation  in  solution,  but  left 
rotation  as  salt. 

The  assumption  that  in  solutions  of  malic  and  tartaric  acids, 
single  molecules  and  molecular  aggregations  occur  at  the  same 
time,  and  possess  opposite  rotations,  would  explain  :  (i)  The 
anomalous  rotation  dispersion  of  the  two  substances  (§46); 
(2)  the  parallel  change  in  rotation  with  increasing  dilution  or 
elevation  of  temperatures  (s  60),  as  both  causes  would  lead 
to  a  breaking  down  of  molecular  aggregates ;  (3)  the 
phenomenon  referred  to  in  §59  in  which  solutions  of  ^-tartaric 
acid  in  mixtures  of  alcohol  and  benzene  or  other  hydrocarbons 
exhibit  left  rotation,  inasmuch  as  these  liquids,  as  is  well 
known,  have  the  power  of  favoring  the  formation  of  molecular 
combinations. 

A  proof  of  aggregations  by  cryoscopic  methods  is  not  pos- 
sible, as  these  do  not  exist  in  dilute  solutions.  In  such 
solutions,  as  shown  in  §  20,  tartaric  acid  has  the  normal 
molecular  weight.  The  further  changes  observed  in  the 
rotation  of  tartaric  acid,  with  great  dilution  (§  55),  find  their 
explanation  in  the  now  possible  electrolytic  dissociation. 

As  may  be  finally  remarked,  phenomena  different  from 
those  referred  to  above  had  already  led  to  the  view  that 
molecular  combinations  exist  in  concentrated  solutions  which 

i  This  has  since  been  shown  by  Walden.     See  Part  VI,  Constants  of  Rotation.    Tr. 


234  SPECIFIC    ROTATION 

break  down  with  increasing  dilution.  Hittorf  explains  in  this 
way  the  abnormal  behavior  of  cadmium  salts  on  electrolysis.1 

64.  d.  Combinations  of  the  Active  Body  with  the  Solvent.  Hydrates. 
— Biot2  attempted  to  explain  the  changes  in  the  specific  rotation 
of  tartaric  acid  on  increasing  dilution  on  the  assumption  of  the 
formation  of  hydrates  containing  more  and  more  water.  But 
thus  far,  it  has  not  been  found  possible  with  this  substance  or 
with  others  to  positively  prove  the  existence  of  such  compounds, 
as  the  methods  based  on  observations  of  osmotic  pressure 
furnish  here  no  information.  As  Nernst3  has  shown,  a  pro- 
gressive formation  or  decomposition  of  hydrates  with 
increasing  dilution  is  in  general  not  possible,  and  for  the 
following  reasons:  If  a  molecule,  A,  with  n  molecules  of 
another  substances  B  (wrater)  enters  into  the  reversible 
reaction, 

A  -f  n  B  =  A  Bn, 

and  the  corresponding  concentrations  are, 

c,     c,     c, 
then  must,  by  the  Guldberg-Waage  law, 

T-  n 

Kc  =  cl  c.t   . 

If  the  molecule  species,  B,  represents  the  solvent,  present  in 
excess,  then  its  concentration,  c.2>  in  comparison  with  ^  and 
c,  is  very  large,  and  it  will  be  but  little  changed  in  the  reaction, 
whatever  direction  this  takes.  Consequently  c2  may  be  com- 
bined with  the  constant  K  and  we  have  : 

-  =  const. ; 
c\ 

that  is,  for  all  concentrations,  the  relation  of  the  hydrated  to  the 
non-hydrated  molecules  must  remain  the  same.  This  law  would 
naturally  no  longer  obtain  if  the  substance  on  solution  should 
form  several  kinds  of  groups,  A,  by  polymerization  or  chem- 
ical decomposition. 

Hydrates  of  definite  composition  are  without  doubt  formed  by 
the  solution  of  certain  active  bodies  in  water.  This  is  indi- 
cated, for  example,  by  the  strong  liberation  of  heat  in  the  case 

1  See  H.  Jahn  :  "  Grundriss  der  Electrochemie,"  Vienna,  1895,  pp.  49  and  57. 

2  Biot:  M6m.  de  I'lnstitut.,  T.  15  (1838). 

8  Nernst :  Ztschr.  phys.  Chem.,  n,  345;    "  Theoretische  Chemie,"  p.  370. 


COMBINATIONS  OF  THE  ACTIVE  BODY  AND  SOLVENT      235 

of  nicotine  (15°  for  24  grams  of  nicotine  and  6  grams  of  water); 
also  by  the  phenomenon  that  strong  solutions  separate,  on 
heating,  into  the  oily  base  and  water.  Further,  as  follows 
from  the  observations  cited  in  §  52,  the  density  of  the  solutions 
increases  with  increasing  addition  of  water,  reaches  a  maxi- 
mum with  the  proportions  65.9  nicotine  to  34.1  water  (corre- 
sponding to  C10H14N2.5H2O)  and  then  rapidly  decreases.  This 
peculiarity  in  the  variations  in  the  specific  gravity  is  not  shown 
howrever,  in  the  continuous  decrease  exhibited  by  the  specific 
rotation,  and  it  may  therefore  be  questioned  if  the  latter  is 
influenced  by  the  nicotine  hydrate. 

The  changes  in  the  rotation  of  aqueous  solutions  of  malic 
acid,  referred  to  in  §  57,  have  been  accounted  for  by  Bremer1 
on  the  assumption  that  the  acid  itself  possesses  right-hand 
rotation  while  the  hydrates, 

COOH— CH.OH— CH2-C(OH)3, 
C(OH)3— CH.OH— CH2— C(OH)S, 

show  left-hand  rotation. 

Further,  the  phenomenon  that  rhamnose  hydrate, 
C6Hi2O3.H2O,  dissolved  in  water  on  the  one  hand,  and  in  cer- 
tain alcohols  on  the  other,  exhibits  opposite  rotation  directions, 
has  been  explained  by  Rayman2  on  the  hypothesis  that  the 
solution  contains  a  hydrate,  C5HnO4.CH(OH)2,  in  the  one  case 
and  in  the  other,  alcoholates,  C5HUO4.  *CH(OH)(OR),  in 
which  a  new  asymmetric  carbon  atom  appears.  The  observed 
specific  rotations  referred  to  C6H12O5  are  the  following: 

Water p  =    5  to  40  [a~\D  =  +    9-2  to  9-43 

Methyl   alcohol . .  p  =  19  [#]  D==  —  10.59* 

Ethyl  alcohol p  =    6.4;  9.3  \oi\D  —    —  10.65;*  IO-°5 

Isobutyl  alcohol . .  p  =    7.3          [<*]  D  —  —    7.3* 
Amyl  alcohol ....  left-rotating4 

Isopropyl  alcohol .  \_a~\n  =  ~t~  ^'6?6 

1  Bremer:  Rec.  trav.  Chim.  Pays-Bas.,  3,  162,  336. 

2  Rayman:  Ber.  d.  chem.  Ges.,  21,  2050. 

3  Rayman  and  Kruis:   Bull.  Sex:.  Chim.   (2),  48,  632;  Schnelle  and  Tollens:  Ann. 
Chem.  (I<iebig),  271,  62;  Jacobi:  Ibid.,  272,  175.     The  solution  of  the  hydrate  in  water 
exhibits  at  first  left  rotation,  but  after  a  time  the  constant  right  rotation  appears. 

4  Rayman:  loc.  cit. 

5  Jacobi:  loc.  cit. 

6  Parizek  and  Sulc  :  Ber.  d.  chem.  Ges.,  26,  1411. 


236  SPECIFIC    ROTATION 

Of  the  left-rotating  alcoholic  rhamnosides  Rayman  was  able 
to  prepare  the  amyl  compound  in  solid  condition.  The  right 
rotation  of  the  solution  in  isopropyl  alcohol  is  explained  by 
Parizek  and  Sulc,1  who  state  that  in  this  case  analcoholate  is 
not  formed.  According  to  Fisher  the  alcohol  glucosides  are 
easily  formed  in  presence  of  hydrochloric  acid.'2 

If  an  active  body  forms  a  true  chemical  combination  with 
the  solvent,  the  resulting  specific  rotation  would  naturally  be 
different  from  that  found  with  an  inert  solvent.  This  would 
be  the  case,  for  example,  with  solutions  of  borneol  in  chloral 
or  bromal.  The  existence  of  such  compounds  in  solution  is 
frequently  assumed,  for  example,  of  turpentine  oil  with  carbon 
disulphide,3  propyl  tartrate  with  benzene,4  alkaloids  with 
alcohol  and  benzene,5  but  that  they  are  formed  has  not  been 
definitely  proved. 

65.  e.  Hydrolysis. — This    phenomenon  occurring  in  salts  of 
weak  acids  or  bases  appears  to  influence  the  rotation  in  some 
instances,  as  already  pointed  out  in  §61,   but  numerical  data 
are  still  lacking.     The  effect  is  probably  slight,  because,  as  is 
well  known,  with  most  salts  but  a  small  portion  suffers  hydro- 
lytic  dissociation  (Shields),6  (Bredig).7 

66.  f.  Small  Variations  in  the  Atomic  Equilibrium  of  the  Active 
Molecule. — The  alteration  in  specific  rotation  shown  by  nearly 
all  bodies  in  presence  of  a  solvent  cannot  be  explained  in  many 
cases,   by  any  of    the  causes  so   far  discussed.      Here,    for 
example,  belongs  the  increase  in  the  specific  rotation  of  cane- 
sugar  by  increasing  dilution  with  water,   where  between  the 
limits?  =  35  to  95  [ar]^  increases  from  65.6°  to  66.6°  (§54)  ; 
further,  the  increase  in  specific  rotation  of  /-turpentine  oil, 
[ar]/>  =     -  37,  by  addition  of  alcohol,   benzene  or  acetic  acid, 
which  liquids  finally  yield  a  maximum  value  of  [<*]  „  =   -38.8°, 

-39.8°,  and  — 40.7°  (§52).  Although  in  thesecases,  as  in 
many  others,  the  increase  or  decrease  in  the  rotating  power  is 
but  small,  it  may  still  be  followed  with  certainty. 

Parizek  and  Sulc:  loc.  cit.\  Sulc:  Ber.  d.  chem.  Ges.,  37,  594. 

Fisher:  Ber.  d.  chem.  Ges.,  a6,  2400. 

Aignan:  Pouv.  Rot.,  Thesis,  1893,  p.  24. 

Freundler:  Bull.  Soc.  Chim.,  [3],  9,  683. 

Wyrouboff:  Jour,  de  Phys.  [3],  a,  180;  Ann.  chim.  phys.  [7],  i,  i. 

Shields:  Ztschr.  phys.  Chem.,  la,  167. 

Bredig  :  Ibid.,  13,  322. 


COMPLEX    SYSTEMS  237 

Phenomena  of  this  order,  as  already  remarked  in  the  first 
edition  of  this  work,  may  possibly  be  accounted  for  by  the 
hypothesis,  that  when  between  the  molecules  of  a  certain 
substance  (turpentine)  other  molecules  (alcohol)  enter,  certain 
modifications  in  the  structure  of  the  first  result  and  of  such  a 
nature  that  in  each  molecule,  the  relative  positions  of  the 
atoms,  their  arrangement  in  space  and  the  conditions  of  their 
motions  are  somewhat  altered.  This  will  follow  in  greater 
degree,  the  larger  the  number  of  added  inactive  particles. 
Observations  of  other  kinds  of  phenomena  have  also  led  to  the 
same  notions  of  possible  slight  perturbations  in  atomic  equili- 
brium, not  sufficient,  however,  to  endanger  the  existence  of  the 
molecule.1 

E.  Specific  Rotation  of  Complex  Systems 

67.  Solutions  of  an  Active  Body  in  Two  Inactive  Liquids — If  the 
change  in  the  specific  rotation  of  the  body  by  each  one  of  the 
solvents  alone  is  expressed  by  the  constants  of  the  equations: 

m  [«]«  =  «  +  &J  +  ctf 

[«].  =  a  +  b,g  +  <#>, 

in  which  a  is  nearly  the  same,  the  action  of  the  mixture  will 
be  given  by 

(II)  [or]  ==  a  +  (^P,  +  b,P,)q  +  (c,Pv  +  cfjf, 

where  100  parts  by  weight  of  the  solution  of  the  active  sub- 
stance contain  q  parts  of  the  inactive  liquid  mixture,  or  i  part 
by  weight  of  the  latter  is  made  up  of  Pl  and  P.2  parts  of  the 
components. 

This  formula  applies,  however,  only  when  the  two  liquids 
mix  with  but  slight  change  in  volume  or  other  physical 
property,  as,  in  the  other  event,  some  modification  in  the 
behavior  of  the  same  with  the  active  body  might  be  expected. 

Rimbach2  investigated  the  relations  obtaining  with  solutions 
of  camphor   in   mixtures   of   acetic  ether  and  benzene.     He 
found,  as  expressing  the  influence  of  the  liquids  separately: 
Camphor  in  acetic  ether     [«]^  =  56.54  —  0.0907  q  -f  o.ooo  401  g.2 
"     benzene  [«]£  =  55-99  —  0.1847  q  +  o.ooo  269  q1 

Then  the  specific  rotations  were  determined  for  a  number  of 

1  See,  for  example,  van 't  Hc^T  :  "  Etudes  de  dynamique  chimique,"  1884,  p.  41. 
-  Rimbach:  Zeit.  phys.  Chem.,  9,  698. 


238 


SPECIFIC    ROTATION 


solutions  which  are  given  below  in  parallel  with  the  values 
found  by  formula  (II).  For  this  calculation  a  was  taken  = 
56.265. 


Mixture. 
9 

Acetic  ether. 
A 

Benzene. 
/I 

Ms 

Cal.—  Obs. 

Observation. 

Calculation. 

49-94 

0.7509 

0.2491      :   4-  51-76° 

51-49° 

-0.27 

64.98 

0.7509               0.2491 

50.86 

50.41 

—  0.45 

90.00 

0.7509               0.2491 

49-63 

48.97 

-0.66 

46.21 

0.5050                0.4950 

50.88 

50.66 

—  0.22 

64.96              0.5050                0.4950 

49-35 

48.77 

-0.58 

79.70              0.5050 

0.4950 

48.06 

47.46 

—  O.6o 

89.49              0.5050 

0.4950 

47-32 

46.67 

—  0.65 

40.16              0.2569                0.7431 

50.35 

50.31 

—  O.O4 

50.13              0.2569                0.7431 

49.14 

48.98 

—  0.16 

65.18              0.2569                0.7431 

47.41 

47-09 

-0.32 

So.OO              0.2569                0.7431 

45.89 

45.36 

-0.53 

89.69              0.2569                0.7431                   44.86 

44-30 

—  0.56 

With  these  mixtures  the  calculated  specific  rotation  was 
always  found  a  little  less  than  that  found  by  observation,  the 
difference  increasing  with  the  dilution  of  the  mixture. 

A  second  series  of  investigations  made  by  Rimbach  on 
solutions  of  right  turpentine  oil  in  mixtures  of  alcohol  and 
glacial  acetic  acid  showed  very  small  differences  between 
observation  and  calculation,  and  sometimes  positive,  some- 
times negative. 

While  in  the  above  illustrations,  the  specific  rotation  with 
mixtures  has  been  found  to  lie  between  those  found  with  the 
components,  it  has  been  noticed  that  in  some  cases  the  first 
may  be  considerably  the  larger.  In  this  event,  a  maximum 
rotation  is  found  for  some  definite  mixture  of  the  two  liquids. 
The  following  are  observations  in  this  line  : 

According  to  Hesse1  cinchonidine  gives  in  concentration, 
c=  2  : 

Dissolved  in  alcohol  of  97  per  cent  by  volume.  [a~\D  =  —  106.9 

"chloroform "              -    83.9 

"  alcohol-chloroform  (1:2) "            —  108.9 

1  Hesse  :  Ann.  Chem.  (Liebig),  176,  219. 


COMPLEX   SYSTEMS  239 

For  anhydrous  cinchonidine  nitrate  and  hydrochloride, 
Oudemans1  obtained  the  following  numbers : 

Hvdro- 
Solvent  ^Nitrate,       chloride, 

Water [<*~\D  =  '-    99-9  -    99-9 

Absolute  alcohol "             —103.2  —104.6 

80  per  cent.-  alcohol  —  20  per  cent.-  water.  "             —  127.0  —  128.7 

89    "       "                           ii    "        "            "    ...  "             —119.0  — 119.6 

According  to  Oudemans  quinidine  hydrochloride  in  concen- 
tration c==  1.89,  for  the  anhydrous  salt,  shows  : 

Dissolved  in  water [#]  D  =  -4-  190.8 

"  "    absolute  alcohol "  199-4 

Dissolved  in  alcohol  of  90.5  per.  cent,  by  weight  "  213.0 

Hesse3  has  followed  the  changes  in  the  specific  rotation  of 
quinine  hydrochloride  (with  2H2O)  with  variations  in  the 
proportions  of  water  and  alcohol  used  as  a  solvent,  employing 
always  the  constant  concentration,  c=  2.  From  the  follow- 
ing data,  in  which  g  gives  the  per  cent,  by  volume  of  alcohol  in 
the  solvent,  it  appears  that  for  g  =  60,  a  maximum  of  rotation 
occurs : 

g  =          o       20      40       50       60      70       So       85       90     97 
[a\D=   -138.8  166.6  182.8  187.5  187.8  182.3  174-8  168.3  160.8  143.9 

Oudemans4  gives  the  following  observations  on  the  specific 
rotation  of  cinchonine  in  mixtures  of  chloroform  and  alcohol : 

I  2  3456 

Chloroform 100.00      99.66      98.74      94.48      86.95       82.26 

Alcohol o  0.34        1.26        5.52       13.05       17.74 

[#]/> +212.0        216.3         226.4         236.6         237.0         234.7 

7  8  9  10  ii 

Chloroform 65.00          44.29          27.54          17.02  o.oo 

Alcohol 35-00          55.71  72.46          82.96        loo.oo 

[tx"]D 229.5          226.6          227.6          227.8          228.0 

A  maximum  is  found  here  which  is  shown  by  graphic 
interpolation  to  occur  with  the  mixture  containing  10  per 
cent,  of  alcohol.  It  is  also  observed  that  in  an  alcoholic  solu- 
tion of  cinchonine,  about  one-half  of  the  alcohol  may  be 
replaced  by  chloroform  without  producing  any  marked  change 
in  the  specific  rotation,  while  on  the  other  hand,  if  in  a  solu- 

1  Oudemans:  Ann.  Chem.  (I,iebig),  182,  49.  50. 

-  By  weight. 

3  Hesse  :  Ann.  Chem.  (I<iebig),  176,  210. 

*  Oudemans  :  Ibid.,  166,  71. 


240 


SPECIFIC    ROTATION 


tion  of  cinchonine  in  chloroform  only  1/300  of  the  latter  is 
replaced  by  alcohol,  an  increase  in  the  specific  rotation  of  4° 
follows. 

68.  Mixtures  of  Two  Active  Liquid  Substances. — If  the   mixture 
consists  of 

pl  parts  by  weight  of  the  one  body  with  specific  rotation  [or^, 
A  "  "  other  "  "  "  "  [«]„ 

then  we  have  as  the  specific  rotation  of  the  mixture  [«],„: 

[al      =  A  I>L+A  [«].. 

A+A 

assuming  that  each  body  has  no  influence  on  the  specific  rota- 
tion of  the  other.  If,  however,  some  such  action  takes  place 
the  observed  specific  rotation  must  depart  more  or  less  widely 
from  that  calculated. 

An  investigation  of  this  question  was  undertaken  by  Ham- 
merschmidt1  with  the  following  substances  : 

Mixtures  of  Right-  and  Left- Rotating   Turpentine. 


Mixture 
No. 

In  100  parts  of  mixture. 

Observed 
rotation  of  the 
mixture. 

Ms 

Calculated 
specific 
rotation. 

Difference. 
Calc.—  Obs. 

Right  oil. 

I,eft  oil. 

100 

.... 

+  17-39° 

.... 

.... 

I 

79-25 

20.75 

+   6.40 

•f     6.4I° 

-f-  o.oi 

II 

60.40 

39.60 

-    3-54 

-    3-55 

+  O.OI 

III 

40.82 

59-18 

-  13-90 

-  13-90 

4-  o.oi 

IV 

20.83 

79-77 

—  28.82 

—  28.80 

—  0.02 

.... 

100 

-  35-50 

.... 

.... 

From  these  numbers  it  is  evident  that  the  specific  rotations 
of  mixtures  of  such  similar  bodies  as  two  turpentine  oils  corre- 
spond exactly  to  the  above  mixture  formula.  It  is  further 
found  by  calculation  that  a  mixture  of  67.13  parts  by  weight 
of  the  right-hand  oil  with  32.87  parts  by  weight  of  the  left- 
rotating  oil  must  be  inactive  optically. 

69.  Solutions  of  Two  Active  Bodies  in  an  Inactive  Liquid. — 
Let  the  mixture  contain  in  100  parts  by  weight  : 

1  Hammerschmidt:  "  Ueber  das  specifische  Drehungsvermogen  von  Gemengen 
optisch  activer  Sui>stanzen."  Inaug.  Dissert.  Rostock  1889. 


COMPLEX   SYSTEMS  241 

A^  per  cent,  of  the  first  active  substance, 

A2  "       "      "    "    second  " 

F    "       "      "    "    inactive  liquid, 

and  let  the  effect  of  the  solvent  on  the  first  active  body  be 
expressed  by 

(I)  [>],  =  «,  +  b,p  +  c,p\ 

and  that  of  the  solvent  on  the  second  active  body  by 

(II)  [a]f  =  a,  +  btp  +  c,p\ 

in  which  formulas  p  gives  the  percentage   amount  of  active 
substance  in  each  solution. 
Then  we  substitute  : 

In  equation  (I)  for/  the  value    .         1-, ; 

«     »    (ID  <•  p  «    -  j00^. 

With  the    specific    rotations    [a]T  and   [a],    so    obtained, 
there  follows  for  the  mixture, 


but  from  the  observed  angle  of  rotation  a  ,n  we  have  the  value, 


In  order  to  judge  of  the  difference  between  observation  and 
calculation,  it  is  preferable  to  compare  the  observed  angles  of 
rotation  directly  instead  of  the  specific  rotations,  from  which  it 
will  be  seen  wrhether  or  not  the  errors  of  observation  are 
exceeded.  The  calculated  angle  of  rotation  follows  by  equating 
the  last  two  formulas,  as  : 


!  2    ,  d 

"!5o~ 

These  deductions  may  be  tested  by  some  experiments  which 
Hammerschmidt1  carried  out  with  aqueous  solutions  contain- 
ing cane-sugar  and  grape-sugar.  The  following  tables  give 
first,  the  observed  data,  and  then  the  calculations,  for  which 
the  interpolation  formulas  of  Tollens  are  used  in  finding  the 
specific  rotations  of  the  two  sugars  : 

1  Hammerschmidt  :  Loc  cit. 
16 


242 


SPECIFIC    ROTATION 


Cane-sugar 
Grape-sugar 


«  p  =  66.386  +  0.015035  p  —  0.0003986  p- 
7,  =  52.500  -7-  0.018796  p  —  0.0005168  p'1 


In  100  parts  by  weight. 

Solu'n 
No. 

Specific 
gravity  of 
solution. 

Observed  angle 
of  rotation  for 
/  =  i.  9992dm. 

Specific 
rotation. 

[«]-. 

Cane- 

Grape- 

Water 

sugar. 
A\ 

sugar. 
A» 

F 

d 

O-m 

Ray  D 

I 

5-°49 

19.490 

75.461 

.09996 

30.14° 

55.830 

2 

9.814 

14.851 

75-335 

.10104 

3I.8I 

58.56 

3 

14.655 

9.863 

75.482 

.10073 

33-06 

61.28 

4 

I9-5I7 

4.892 

75.591 

.10054 

34-25 

63.78 

5 

19.558 

4.855 

75.587 

.10056 

34.30 

63-85 

Solu'n 

Cane- 
sugar. 

Grape- 
sugar. 

Cane- 
sugar. 

Grape-sugar. 

Calculated 
angle  of 
rotation 

No. 

loo  A] 

100  At 

[a]i 

LUJ2 

Rav  n 

Calc.-Obs. 

A\  +  F 

Az  +  F 

Ray/? 

RayD 

I 

6.271 

20.526 

66.464° 

53-104° 

30.14° 

0.00° 

2 

11.526         16.467 

66.506 

52.950 

31.68            —0.13 

3 

16.259 

H-557 

66.525 

52.786 

32.91 

-0.15 

4 

20.521 

6.078 

66.527 

52.633 

34-23 

—  0.02 

5 

20.556 

6.035 

66.527 

52.632 

34.25 

-0.05 

From  the  slight  deviation  of  the  calculated  angle  of  rotation 
from  the  observed  it  follows  that  cane-sugar  and  grape-sugar 
do  not  sensibly  affect  each  other  in  their  rotating  power. 

An  agreement  equally  close  is  found  writh  aqueous  solutions 
of  mixtures  of  cane-sugar  and  raffinose  (meletriose).  The 
specific  rotation  of  each,  and  especially  of  the  latter,  is  but 
slightly  dependent  on  the  amount  of  water,  and  we  can  take 
as  constants  for  : 

Cane-sugar [«]  D  =  -f-    66.5 

Raffinose [#]  n  =  -f  104.5 

In  such  cases  we  can  employ  in  the  above  mixture  formula 
the  concentrations  c{  and  c.2  in  place  of  the  weight  per  cents. , 
A^  and  A^  that  is,  we  can  consider  the  number  of  grams  of 
each  substance  dissolved  in  100  cc.  of  solution,  from  which, 


and  am  = 


I  OO 


Experiments  by  Creydt1  have  given  the  following  results  : 

1  Zeit.  Ver.  fur  Riibenzucker-Ind.,  1887.  p.  153. 


PRESENCE   OF   INACTIVE    BODIES 


243 


TOO  cc.  solution 
contains. 

Angle  of  rotation  [arl  m 
for  tube  length  7=2  dm. 

Specific  rotation. 

M- 

Cane- 
sugar. 

Raf- 
finose. 

Observed 
for  D. 

Calculated 

Calc.— 
Obs. 

Observed 
for  D. 

Calculated. 

Calc.— 
Obs. 

i6g 

4g 

-f  29.61 

+  29.64 

+  0.03 

+  74-ot 

-f  74-10 

-ho.oS 

17" 

3" 

28.92 

28.88       —  0.04 

7229 

72.20 

—  0.09 

18" 

2  " 

28.11 

28.12 

+  O.OI 

70.28 

70.30 

-+-  0.02 

19" 

I" 

27-37 

27.37           o.oo 

68.43 

68.43 

0.00 

Somewhat  greater  differences  between  observation  and 
calculation  were  obtained  by  Hammerschmidt1  with  mixtures 
of  ^/-camphor  and  /-santonin  dissolved  in  chloroform. 

70.  Addition  of  Inactive  Bodies  to  Solutions  of  Active  Substances. — 
According  to  the  nature  of  the  two  substances  mixed,  the 
increase  or  decrease  in  the  rotating  power  noted  depends  on  a 
change  in  the  chemical  equilibrium,  the  degree  of  dissociation, 
or  on  the  formation  of  new  compounds.  Most  of  the  investi- 
gations carried  out  in  this  field  deal  with  tartaric  acid  and 
malic  acid,  or  with  different  sugars.  Among  these  the 
following  may  be  considered. 

A .    Tartaric  Acid  and  Malic  Acid. 

a.  Influence  of  Alkali  Salts  on  the  Rotation  of  Tartrates. — A 
series  of  investigations  carried  out  by  lyong2  relates  to  potas- 
sium sodium  tartrate,  KNaC4H4O6.4H2O,  the  specific  rotation 
of  which  changes  but  little  within  the  limits,  c  =  5  to  45,  and 
which  may  be  given  as  [«]™  =  22.10.  20  grams  of  Rochelle 
salt  with  5,  10,  15,  or  20  grams  of  different  alkali  salts  were 
dissolved  to  make  100  cc.  of  solution  and  the  variations,  J, 
from  the  value  22.10  were  determined.  These  were  found  to 
be  partly  positive  and  partly  negative,  and  increased  with 
increased  amounts  of  the  alkali  salts.  In  the  following  table 
the  results  are  given  which  were  found  with  5  and  20  grams 
of  the  salts  (or  with  other  amounts  designated  in  parentheses)  : 

1  Hammerschmidt  :  Loc.  cit.,  p.  22. 

2  Long :  Am.  ].  Sci.  Arts,  [3],  36,  351  (1888). 


244 


SPECIFIC    ROTATION 


Increase  in  22.  10  by  A. 

Decrease  in  22.10  by  A. 

Given  by 

Amount  of  salt. 

Given  by 

Amount  of  salt. 

5 
grams. 

20  grams. 

5  grams. 

20  grams. 

KC1  . 

A 

0.62 
0.62 
0.19 
0.36 
0.50 
0.38 
0.42 

0.47 

0.48 
0-37 

A 

1-33 

1.  01 

0.85 

1.37 

0.63  (10) 
o.73 

1.02 

1.  00 
0.63   (I5) 

0.49  (10) 

NaCl  

A 

0.30 
0.21 
0.38 

0.43 
0.19 

0.20 
0.24 
0.15 

A 

2.35 
1.  00 
1.03 

1.60 
0.52 

1.78 
1.19 
0.98 
0.28(10) 
1.41(10) 

TTTJr 

NaBr    

KI  

NaNOo   . 

KNO        

Na  SO    . 

Kqr» 

Na^HPO.-f  I2aq 
NaH2PO2  +  aq  .  . 
Na2S203  +  5aq.. 
NaC2H302-f3aq 
Na2B4O7  +  10  aq 
Na.  WO    

JOU4    

KSCN  

~KC  H  O 

K,C204+aq.... 
NH  Cl  

jjjj  gr  

LiCl  

Tl  SO  . 

1.67(6.75) 

3-43 

NH4SCN   

(NH4)2C204  +  aq 

0.41 

The  specific  rotation  of  potassium  sodium  tartrate  is  accord- 
ingly increased,  in  the  concentrations  employed,  by  addition 
of  potassium  or  ammonium  salts,  while,  on  the  other  hand, 
sodium  salts,  lithium  chloride,  and  thallium  sulphate  cause  a 
decrease.  The  reason  for  these  opposite  actions  is  not  clear, 
and  no  investigations  have  been  made  to  show  whether  or  not 
they  hold  good  in  dilute  solutions.  The  strongest  effect  is 
found  with  thallium  sulphate. 

Neutral  potassium  tartrate  also,  as  shown  by  Schiitt,1 
exhibits  a  slight  increase  in  specific  rotation  by  addition  of 
potassium  chloride,  and  a  decrease  with  sodium  chloride.  The 
following  mixtures  were  made  and  the  polarization,  p,  found 
in  a  2-dm.  tube  with  a  half-shadow  instrument  having  the 
Ventzke  sugar  scale.  From  these  values  the  specific  rotations 
\a\n  were  calculated:2 

1  Schiitt:  Ber.  d.  chem.  Ges.,  31,  2586. 

2  On  the  assumption  that  1°  Ventzke  (ray  j)  =  0.346  angular  degree  (ray  /?). 


PRESENCE   OF   INACTIVE   BODIES 


245 


In  100  cc.  solution. 

/*. 

Diff. 

[«]*. 

Diff. 

40  gm. 
40    " 

tartrate  —  8  gm. 

i  < 

KC1... 

66.8 
65  8 

1.0 

28.89 

28  A.6 

0-43 

40    * 

-f-  8  gm.  > 

62.8 

3-o 

27.16 

1.30 

30  gm. 

10   " 

tartrate  -f  14  gm. 
i  < 

KC1.. 

49.9 

,.0    - 

1.2 

28.78 

oft  08 

0.70 

ou 

30  " 

-|-  14  gm. 

NaCL. 

40.7 

44.7 

4.0 

25.78 

2.30 

20  gm. 

20     " 

tartrate  —  22  gm. 

KC1-. 

33.3 

ii  8 

1.5 

28.80 

27  ^1 

1.29 

20     " 

+  22gm. 

NaCL. 

51.0 

27.5 

4.3 

*/-jl 
23-79 

3-72 

10  gm. 

IO     '  ' 

tartrate  -f-  25  gm. 

KC1.. 

16.7 

1.  1 

28.89 

1.90 

10     " 

"          +  25gm. 

NaCL. 

13.2 

2.4 

«o.yy 

22.84 

4.15 

The  effect  varies  with  the  proportions  in  which  the  substances 
are  mixed.  On  this  difference  in  behavior  of  potassium 
chloride  and  sodium  chloride  Schiitt  has  based  a  method  for 
the  quantitative  analysis  of  a  mixture  of  the  two  salts.  See 
PartV. 

A  slight  decrease  in  the  rotation  of  sodium  tartrate  by 
addition  of  sodium  nitrate  was  observed  by  Th.  Thomsen.1 

The  specific  rotation  of  tartar  emetic  (K.SbO.C4H4O6iH2O) 
for  c  =  5,  [a]20:=-|-  141.27,  was  found  by  Long8  to  be 
diminished  by  addition  of  potassium,  sodium  and  ammonium 
salts,  and  in  greater  degree,  the  more  of  the  salts  are  present. 
The  decrease  by  KC1,  KBr,  KNO3,  NaCl,  NaNO3,  NH4C1,  and 
NH4NO3  is  slight,  while  for  sodium  acetate,  sodium  phosphate, 
and  sodium  carbonate  it  is  considerable,  when  these  salts  are 
added  in  amount  insufficient  to  produce  a  precipitate.  Thus, 
10  grams  of  sodium  acetate  reduce  the  specific  rotation  given 
above  to  123.59,  and  small  amounts  of  sodium  carbonate  to 
55.8  even.  According  to  Long,  the  action  of  these  salts 
depends  on  this,  that  the  antimonyl-potassium  tartrate  is 
partly  decomposed  into  alkali  tartrates  and  compounds  contain- 
ing SbO  and  K  with  acetic,  phosphoric,  and  carbonic  acids. 

1  Thomsen  :  J.  prakt.  Chem.,  [2],  34,  83. 

2  Long  :  Am.  J.  Sci.   Arts,  [3],  38,  264  ;  40,  275. 


246  SPECIFIC    ROTATION 

b.  Influence  of  Boric  Acid  on  the  Rotation  of  Tartaric  Acid.  — 
The  marked  increase  in  activity  which  is  found  here  was 
observed  first  by  Biot1  in  1837  and  later  made  the  subject  of 
lengthy  investigations.2  In  order  to  follow  the  changes  which 
occur  where  water  and  boric  acid  are  both  added,  he  showed 
first  that  the  rotation  of  the  tartaric  acid  is  increased  by  each 
one  of  these  bodies  taken  alone  ;  that  is,  first,  by  melting  the 
tartaric  acid  with  increasing  amounts  of  boric  acid  to  form 
glass-like  masses,  and  secondly,  by  dissolving  the  acid  in 
increasing  quantities  of  water.  If  now  an  aqueous  solution  of 
tartaric  acid  be  treated  with  boric  acid,  the  observed  specific 
rotation  depends  on  these  two  conditions  : 

i.  On  the  relation  of  the  tartaric  acid  to  the  boric  acid. 
The  latter  increases  the  rotation,  as  borotartaric  acid  is 
formed,  and  this  has  a  greater  rotating  power/*  If  the  relation 
of  tartaric  acid  to  water  is  maintained  constant,  the  increase 
which  the  specific  rotation  of  tartaric  acid  experiences  by 
addition  of  varying  amounts  of  boric  acid,  /?,  may  be  expressed 
by  the  formula 


in  which  the  constants,  A,  B,  C,  are  to  be  found  by  a  series  of 
observations. 

2.  On  the  amount  of  water.  On  the  one  hand,  this  acts  to 
increase  the  rotation  of  the  tartaric  acid,  but  on  the  other,  it 
causes  hydrolytic  decomposition  of  the  borotartaric  acid,  and 
in  consequence,  a  decrease  in  the  rotating  power.  Experi- 
ments showed  that  as  long  as  the  mixture  contained  for  i  part 
of  tartaric  acid  less  than  0.088  part  of  boric  acid,  the  rotation  is 
increased  by  gradual  increase  in  the  amount  of  water.  If  the 
relation  between  tartaric  acid  and  boric  acid  is  exactly 
i  :  0.088,  the  specific  rotation  remains  the  same  for  all 
dilutions,  because  then,  through  the  increasing  hydrolysis 
of  the  borotartaric  acid,  the  activity  is  decreased  in  the  same 
degree  in  which  it  would  be  increased  by  the  influence  of  the 

i  Biot  :  Mem.  de  1'Acad.,  16,  229. 

*  Biot  :  Ann.  chim.  phys.,  [3],  II,   82  (1844)  ;  29,  341,  430  (1850)  ;  59,  229  (1860). 

8  Mono-  or  diboryltartaric  acid.  Not  stable  in  solid  condition.  (Duve  :  Jahre.s- 
bericht,  1869,  p.  540.)  Dubrunfaut,  Compt.  rend..  43,112,  assumes  the  formation  of 
the  compound,  HSBO3  +  2C4H«O8. 


PRESENCE   OF   INACTIVE    BODIES  247 

added  water  on  the  tartaric  acid.  Finally,  if  the  mixture 
contains,  for  i  part  of  tartaric  acid,  more  than  0.088  part  of 
boric  acid,  then  the  first  action  is  the  stronger  and  the  rotation 
falls  by  increasing  addition  of  water.  In  general,  in  these 
cases,  the  changes  may  be  expressed  by  the  formula 
[or]  —  A  -f  Bq,  in  which  q  represents  the  amount  of  water 
in  TOO  parts  by  weight  of  the  mixture.  If  all  three  com- 
ponents are  varied,  a  maximum  rotation  is  found  for  definite 
weight  relations.  The  papers  of  Biot  contain  a  large  amount 
of  numerical  data,  which  are  based  on  red  light  with  a  wave- 
length of  about  635>^cf.  ty 

With  reference  to  the  D  ray,  for  which  but  few  investiga- 
tions have  been  made,  the  extent  of  the  influence  of  boric 
acid  on  the  specific  rotation  of  tartaric  acid  may  be  seen  from 
the  following  numbers  (Koch):1 

In  100  cc.  of  solution.  Mol.  relation.  ^        °^  *^e  tartaric  acid. 


Tartaric  acid. 
Grams. 

Boric  acid. 
Grams. 

Tartaric 
acid. 

Boric 
acid. 

With                  Without 
boric  acid.          boric  acid. 

32.13 

3.32                4                  i              -  29.80° 

+  10.86° 

29.11 

24ol 
16.63 

4.01 
5.06 
6.87 

3 

2 
I 

I 
I 
I 

34.09 
39.58 

43-44 

11.25 
11.85 
12.88 

By  determining  the  electrical  conductivity  of  a  large  num- 
ber of  different  mixtures  of  tartaric  acid,  boric  acid,  and  water, 
Magnanini2  also  was  able  to  prove  the  existence  of  a  boro- 
tartaric  acid  compound,  which  conducts  well,  and  the  electro- 
lytic dissociation  of  the  same  by  increasing  addition  of  water. 

On  the  rotation  of  the  alkali  boryl  tartrates  see  §  61. 

Magnanini  found  that  other  oxy-acids  also  experience  an 
increase  in  conductivity  by  addition  of  boric  acid  ;  thus,  lactic 
acid,  glyceric  acid,  oxybutyric  acid,  and  malic  acid.3  An 
increase  in  optical  activity  might  be  expected  therefore  with 
these,  which,  with  reference  to  malic  acid,  was  already  pointed 
out  by  Pasteur.4 

1  P.  Koch:  "Einwirkung  weinsaurer  Verbindungen  auf  polarisirtes  Licht." 
Inaug.-Diss.,  Tubingen  1869. 

-  Magnanini:  Zeit.  phys.  Chem.,  6,  67;  Gazz.  chim.  ital.,  20,  4535  2"»  ^  I34- 

3  Magnanini  :  Gazz.  chim.  ital.,  21,  II,  215.     Ber.  d.  chem.  Ges.,  24,  III,  894. 

4  Pasteur:  Ann.  chim.  phys.,  [3],  59,  243. 


248 


SPECIFIC    ROTATION 


c.  Action  of  Molybdates  and  Tungstates  on  Tartaric  Acid. — 
On  this  question  extended  investigations  have  been  carried  out 
by  Gernez  which  cover  the  following  salts  : 

Sodium  molybdate Na2MoO4  +  2  Aq,  Compt.  rend.,  104,  783. 

Lithium  molybdate Li2MoO4,  Compt.  rend.,    108,942. 

Magnesium  molybdate..  MgMoO4,  Compt.  rend.,  108,  942. 
Ammonium  molybdate..   (NH4)6Mo7O24  +  4  Aq,  Compt.  rend.,  105,  803. 
Potassium  tungstate-  •  •.  K2WO4,  Compt.  rend.,  106,  1529. 
Sodium  tungstate Na2WO4  +  2  Aq,  Compt.  rend.,  106,  1527. 

In  these  investigations,  solutions  were  employed  which  con- 
tained always  in  100  cc.,  2.5  grams  of  tartaric  acid  and  increas- 
ing amounts  of  the  salts,  added  in  molecular  proportions  to  the 
tartaric  acid.  Gernez  reports  only  the  angles  of  rotation  found 
in  a  tube  1.057  dm.  in  length.  The  following  table  contains 
the  complete  numerical  data  for  ammonium  molybdate,  and  in 
the  last  column,  the  specific  rotations  (calculated  by  Dr. 
Berndt),  which  correspond  to  the  tartaric  acid  in  the  different 
solutions  : 

AMMONIUM  MOLYBDATE. 


Mol.of  salt 
to  i  mol.  of 


Grams  of  salt  to 
2.5  grams  of 


ff^for 


i<±  i  iaru:  aiziu 

in  Vise  mol. 

tartaric  acid. 

/  =  1.057  dm. 

i_    j  •" 

0 

o.ooo 

0° 

11' 

+    13-2° 

I 

0.161 

i 

2 

39-o 

2 

0^22 

I 

41 

63-6 

3 

0.482 

2 

21 

88.9 

4 

0.644 

2 

57 

112 

6 

0.965 

4 

5 

154 

8 

1.288 

5 

3 

191 

12 

I-93I 

6 

52 

260 

16 

2-575 

8 

49 

334 

24 

3.863 

13 

22 

506 

32  =  '/4 

5.150 

17 

38 

667 

40 

6.438 

19 

50 

750 

|     42.66  =  >/» 

»        6.866 

20 

39* 

781* 

48 

7.725 

2O 

36 

780 

56 

9.013 

20 

35 

779 

64  =  V. 

10.300 

19 

47 

749 

96 

15.450 

17 

28 

66  1 

128  =  i 

20.600 

16 

44 

633 

192  =  i% 

30.900    , 

16 

33 

626 

PRESENCE    OF    INACTIVE    BODIES 


249 


For  the  other  salts  Dr.  Berndt  has  calculated  the  following 
specific  rotations  of  tartaric  acid  from  the  data  of  Gernez: 


Added  salt  in 
1  10  mol.  for  each 
mol.  of 
tartaric  acid. 

Tungstate  of 

Molybdate  of 

Potassium. 

w? 

Sodium. 

Sodium. 

WZ 

Lithium.      Magnesium. 

0 

14.0° 

14.0° 

13.2°               14.0°               14.0° 

V*  =  \:u  mol. 

28.4 

27.6 

31.4                 25.3 

23-4 

i=V»    " 

41.6 

40.5 

5I.I                 38.6 

33-3 

2  =  V6        " 

69.3 

65.6 

89.7                62.4 

53-3 

3=V«     " 

95.4 

91.6 

128 

87-7 

72.2 

4  =  Vi      " 

119 

117 

167 

112 

91.5 

5 

143 

141 

206 

137 

no 

6  =  */,      " 

169 

I64 

243 

162 

129 

7 

196 

185 

288 

186 

149 

8 

223 

207 

334 

209 

169 

9 

252 

228 

383 

235 

189 

10 

281 

247 

435 

255 

209 

n 

308 

264 

479 

277     - 

229 

12  =  I          " 

327* 

277* 

517* 

299 

248 

13 

3J8 

271 

330               272 

14 

.. 

.. 

513               358               294 

IS' 

270 

2*1 

512 

383 

3i8 

16 

.. 

.. 

.. 

413 

343 

17 

.. 

438 

368 

18 

241 

222 

505 

462 

394 

21 

.. 

210 

483 

463 

24  =  2 

211 

I99 

498 

484*             523* 

36-3          " 

-. 

170 

482 

468               509 

48  =  4       " 

.. 

154 

473 

457               495 

60=,  5       " 

" 

140 

455 

450               478 

It  is  seen,  therefore,  that  the  specific  rotation  of  tartaric 
acid  increases  on  addition  of  increasing  amounts  of  the  salts  to 
a  maximum,  after  which  a  decrease  follows  which  is  marked 
with  the  tungstates,  but  slight  with  the  molybdates.  These 
maximum  points  correspond  to  definite  molecular  proportions 
between  the  tartaric  acid  and  the  salts,  and  in  fact  to  : 


3  C4H606 


i  (XH4)6Mo7O24  —  4  aq 
i  K2\VO4 

2  aq 


1  Na-MoO4  -f  2  aq 

2  Li,MoO4 


2  MgMoO4 

The  remarkably  great  increase  in  the  specific  rotation  of 
tartaric  acid,  which,  for  example,  with  ammonium  molybdate 


250 


SPECIFIC    ROTATION 


reaches  a  value  sixty  times  the  original,  may  be,  without  doubt, 
ascribed  to  the  formation  of  complex  acids.  Rosenheim1  has 
already  shown  that  tungstic,  molybdic,  and  vanadic  acids  form 
such  compounds  with  oxalic  acid. 

d.  Action  of  Molyb dates  and  Tungstates  on  Ordinary  Malic 
Acid. — Investigations  on  this  point  are  also  due  to  Gernez. 
They  deal  first  with  the  behavior  of  : 

Ammonium  molybdate.  ••  (NH4)6Mo7O24  -f  4Aq,  Compt.  rend.,  109,  151. 
Sodium  molybdate NajMoO^  -f-  2  Aq,  Compt.  rend.,  109,  769. 

In  each  case  i .  1 1 66  grams  of  malic  acid  were  dissolved  with 
increasing  amounts  of  the  salts,  P,  to  make  12  cc.,  and  the 
angle  of  rotation,  aDt  was  found  in  a  tube  1.057  dm.  l°ng  at  a 
temperature  of  17°.  The  following  table  does  not  give  all  the 
solutions  tested  by  Gernez,  but  only  those  with  the  numbers 
added  ;  in  the  fourth  column  the  specific  rotations  of  the  malic 
acid,  calculated  by  Dr.  Berndt,  are  given  : 


Ammonium  molybdate. 

Sodium  molybdate. 

No.  of 
solution. 

Grams 
salt. 
P. 

4 

M* 

z 

No.  of 
solution. 

Grams 
salt. 
P. 

<* 

M3. 

z. 

I 

0.000 

-    0.20C 

-        2.0° 

I 

0.000 

—     0.20° 

—        2.0° 

2 

0.013 

-     0.40 

4.1 

3 

0.084 

1.  12 

-     11.4 

4 

0.054 

-     0.97 

9-9 

5 

0.336 

-     3-72 

-    37-8 

5 

0.107 

-     1.70          -     17.3 

6 

0.504 

'      5.48 

-    55.7 

6 

0.191 

-     2.75          -     28.0 

7 

0.672 

-      7-25 

-    73-7 

8 

0.282 

-     3.82         -     38.8 

9 

i.ooS6 

-     9-07 

-    92.1 

M 

10 

0.429 

-    4-95 

—    50-3 

10 

1.176 

—     5.20 

-    52-9 

1 

H 

0.572" 

-    5-32       -    54-i 

M, 

ii 

1-344 

1.52 

15.5 

16 

0.644 

-    4-93       -    50-1 

12 

I.5I3 

-r    3.02 

-    30.7 

J?i 

18 

0.736 

-    4.17       -    42.4 

14 

1.848 

i-  11-03 

4~   112.  2 

20 

0.792 

-    340 

—    34-6 

15 

2.0I77 

f  14.02 

f   142.5 

M.L 

22 

0.936 

I.OO      —      10.2 

17 

2.353 

+    8.68 

-f    88.2 

23 

0.966 

-     0.42                   4.3 

D 

19 

2.62 

26.6 

24 

i  .0303 

-f     0.83      +        8.4 

J\. 

20 

2*857 

4    0.32 

+      3-3 

26 

1.144 

4-    3.23           32.8 

21 

3.025* 

-   0.83 

8.4 

R-i 

28 
29 

1.288 
1-395 

-    7.20    +    73.2 
f  10.35     f  105.3 

24 
26 

3.5299 
3-865 

-    i-55 

—     I.OO 

-    15-8 

—      10.2 

M, 

32 

1.717*  4-  20.92 

4-  212.7 

27 

4-0331" 

—    0.50 

5-1 

36 

2.146 

f  36.22 

f  368.2 

28 

4.201 

o.oo 

0.0 

jf 

40 

2-S755 
3.863 

r  52.47 
4-  72.00 

f  533-5 
-  731-9 

30 

4.538 
5.042 

4-   0.87 
4-    2.27 

4-      8.8 
19-3 

46 

5.!5ofl 

r  72-80 

f  74o.i 

M, 

36 

5.546 

3-95 

-    40.2 

48 

6.008 

r  72.33 

r  735.3 

39 

-    7.17 

72.9 

49  J  6.438 

4-  72-00 

+  731.9 

41    8.067" 

+  10.25 

f  104.2 

Rosenheim :  Ztschr.  anorg.  Chem.,  4,  352  ;  Her.  d.  chem.  Ges..  26,  II,  1191. 
Equals  Vi8  niol.  •  Equals  Vs  mol.  9  Equals  1.75  mols. 

Equals  '/io  mol.  7  Equals  i  mol.  10  Equals  2  mols. 

Equals  V«  mol.  8  Equals  1.5  mols.  "  Equals  4  mols. 

Equals  V«  mol. 


PRESENCE   OF   INACTIVE    BODIES  251 

From  the  above,  it  is  evident  that  the  relations  are  much 
more  complicated  than  with  tartaric  acid,  inasmuch  as  shown 
by  the  letters  under  Z,  not  only  are  there  points  of  maximum 
rotation  (  J/)  but  points  of  change  in  the  direction  of  rotation 
or  reversal  R  ;  increasing  amounts  of  ammonium  molybdate 
cause  at  first  an  increase  in  the  original  levorotation  which 
grows  to  a  maximum,  then  decreases,  and  finally  changes  to 
dextrorotation  which  increases  very  rapidly,  but  at  last  falls 
a  little.  With  sodium  molybdate  there  are  found  three 
inactive  concentrations  and  three  points  of  maximum  rotation 
of  which  two  are  on  the  side  of  levorotation,  and  one  on  that 
of  dextrorotation.  The  curve  expressing  these  changes  would 
have  a  zigzag  form.  Finally,  it  may  be  remarked  that  the 
characteristic  points,  M  and  R,  frequently  correspond  to  con- 
centrations at  which  there  is  a  definite  molecular  relation 
between  the  malic  acid  and  added  salts. 

Further  investigations  of  Gernez  are  concerned  with  the 
action  of  the  following  salts  on  the  rotation  of  malic  acid  : 

Potassium  tungstate  ..........   K.,\VO4    \  ^ 

_,.  -  ..   *    f  Compt.  rend.,  1  10,  1365. 

Sodium  tungstate  .............    >.  a.A\  O^  i 

Lithium  molybdate  ...........  Li  MoO    ^ 

Magnesium  molybdate  ........  MgMoO\  }  C°mpt  rend"  II0'  ^ 

Sodium  potassium  molybdate.  -  K,Na4Mo3O1.,  -  14  Aq  1  Compt.      rend., 

Acid  sodium  molybdate  .......  Xa6Mo:O24  -  22  Aq      I      m,  792. 

Potassium  phosphomolybdate  •  K,P2Mo5624 

Sodium  phosphomolybdate  ----  Na3P,Mo56.,3  —  14  Aq  I  Compt.      rend., 

Ammonium  phosphomolybdate  (XH  )-P,AIo-O,  *      112,226. 


)-P,AIo-O, 

The  relations  appearing  here,  are,  in  general,  similar  to  those 
found  with  sodium  and  ammonium  molybdates. 

B.   Sugars. 

a.  Changes  in  the  Rotation  of  Cane-Sugar  by  Alkalies  and 
Salts.  —  As  a  great  many  investigations,  carried  out  largely 
with  reference  to  saccharimetry  have  shown,  the  following 
bodies  all  cause  a  decrease  in  the  rotation  : 

Hydroxides  of  the  alkali  and  alkali-earth  metals. 

Chlorides,    nitrates,    sulphates,   carbonates,    phosphates,   acetates  and 
citrates  of  the  alkali  metals. 

Borax, 

Magnesium  sulphate, 

Chlorides  of  the  alkali-earth  metals. 


252 


SPECIFIC    ROTATION 


The  action  of  these  substances  increases  with  increased 
addition  of  the  same,  and  so  as  to  reduce  the  specific  rotation 
of  cane-sugar  from  -+-  66.7°  to  about  60°. l 

On  the  behavior  of  the  chlorides  of  the  alkali  and  alkali- 
earth  metals,  the  extended  experiments  of  Farnsteiner2  have 
given  the  following  specific  rotations  [a]^  : 


i  Part  of  cai 

le-sugar  and 

Parts  of  water. 

3  . 

5 

10 

Without  salt  . 

66.60° 

66.67° 

66.75° 

KC1  

1  08-; 

5-1  55 

6/1  cc. 

NaCl 

1  004 

62  47 

U^OO 

6*  80 

LiCl  

i  <x>8 

l.WO 

6l   e.7 

6-;  18 

TCaOl 

IO7O 

Ac  QC 

66  10 

66  ac. 

SrCl  

I   OQ6 

"o-Vj 
64  12 

Ac  on 

UU'OO 

6^  8c, 

OaOl 

o  006 

62  Co 

6l  42 

U0'0v) 

M^Cl    . 

u.yyu 
12  ^O 

»*o»D« 

62  17 

67  70 

Ac    7Q 

VJ0!OV-' 

The  effect  of  the  salts  becomes  weaker  with  increased  dilution. 
It  is  further  evident  that  the  decrease  in  rotation  brought 
about  by  nearly  equal  weights  of  salts  is  greater,  the  lower 
the  molecular  weight  of  the  chloride. 

Borax,  like  the  other  alkali  salts,  causes  a  decrease  in  the 
specific  rotation  of  cane-sugar.  Muntz:{  found  the  following 
values  when  he  examined  solutions  obtained  by  mixing  10 
grams  of  cane-sugar  in  100  cc.  with  increasing  weights  of 
borax  : 

Borax  =    o        0.5         i         2          3          4          5         7. 5  grams 
[a]  ^=66. 7    65.9    65.0    63.5    62.5     61.6    61.1     60.5° 

The  effect  of  increased  addition  of  salts  has  been  followed  in 
most  cases  only  to  a  low  limit.  More  extended  investigations 
have  been  carried  out  by  Farnsteiner4  with  reference  to  cal- 

1  A  complete  compilation  of  observations  is  found  in  I,ippmann's  "Chemie  der 
Zuckerarten." 

J  Farnsteiner:  Her.  d.  chem.  Ges.,  33,  II,  3570. 
8  Miintz  :  Ztschr.  Riibenzuker-Ind.,  26,  735. 
*  Farnsteiner  :  Ber.  d.  chem.  Ges.,  23,  3572. 


PRESENCE   OF   INACTIVE   BODIES 


253 


cium  chloride,  and  these  have  shown  that  following  the  first 
observed  decrease  in  the  rotation,  an  increase  later  appears, 
when  the  salt  addition  passes  a  certain  limit.  To  a  solution 
of  i  part  of  sugar  in  8.643  parts  of  water,  the  following 
amounts  of  calcium  chloride  were  added  : 


No.  of  the  sol. 

i 

2 

3 

4 

5 

CaCl    . 

0 

O  O55 

2   751 

2  Qo8  parts 

t//|  17-5 

£(L    _  . 

U-VOO 
fr    .  T 

.yiy 
(•     __ 

•'•/DO 

f\1    At 

<*\D 

OO.74 

05.41 

64.50 

^3-5° 

03.41 

No.  of  the  sol. 

6 

7 

8 

9 

10 

CaCl    

5  676 

5087  Darts 

\ct\  I7  5    . 

.uq.u 
f.~   /J-J-jf 

•195 
f-  ,  _ 

•35° 

Ar  A  A 

J.U/U 

/:/;  ,c 

•V°/  rai 
/:-  CQ 

L"  J  D    - 

°3-23 

6345 

05.06 

o°-35 

The  minimum  (*)  of  rotation  is  found  with  solution  No.  6. 
In  solution  No.  10  the  sugar  shows  a  stronger  specific  rotation 
than  it  does  without  addition  of  salt. 

It  has  been  observed  with  ammonia  also  that  in  its  concen- 
trated solutions  (16  to  24  per  cent.  NH3)  it  occasions  an 
increase  in  the  rotation  of  sugar,  while  in  dilute  solution  it 
produces  a  very  small,  or  possibly  even  no,  decrease  (Ost).1 

b.  Dextrose  and  Calcium  Chloride. — It  has  been  observed 
here  that  the  rotation  is  increased  by  addition  of  the  salt. 
Rimbach2  found  the  following  values  for  \oi\  D  : 


Strength 
of  the 
CaClo  solution 

Dextrose  in  100  parts  by  weight  of  the 
whole  solution. 

used. 

Per  cent. 

3° 

20 

IO 

5 

0.00 

55-0° 

55-4° 

55.8° 

56.1° 

10.02 

55-6           55-5 

54-8 

54-9 

19.94 

60.7 

60.5 

|    60, 

60.4 

With  the  5  and  10  per  cent,  dextrose  solutions  a  slight 
decrease  in  the  rotations  is  at  first  observed. 

c.  Action  of  Borax  on  Bodies  of  the  Mannitol  Group. — While, 
as  remarked  above,  the  effect  of  borax  is  to  decrease  the  rota- 

1  Ost  :  Neue  Ztschr.  fur  Riibenzucker-Ind.,  9,  41. 
J  Rimbach:  Ztschr.  phys.  Chem.,  9,  707. 


254 


SPECIFIC    ROTATION 


tion  of  cane-sugar,  it  produces  an  increase  of  rotation  in  the 
alcohols  of  the  glucose  group.  The  phenomenon  was  first 
observed  by  Vignon  with  mannitol,  and  later  E.  Fischer  found 
the  same  behavior  in  the  pentitols,  hexitols,  etc.,  discovered 
by  him.  Many  of  these  bodies,  which  from  their  constitution 
should  be  active  and  which  are  not  racemes,  show  in  pure 
aqueous  solution  either  no  rotation  or  a  very  small  one;  but 
this  may  be  developed  by  addition  of  borax  to  the  solution. 
The  extent  of  the  rotation  caused  in  this  way  may  be  seen 
from  the  table  below,  the  specific  rotations  being  calculated  in 
most  cases  from  the  data  in  the  original  papers: 


Without 
borax  . 

Mi 

With  borax. 
In  100  cc.  solution. 

Observer. 

Sugar. 

Borax. 

Ma 

0[-0.25]> 

<  1 

0[-2.04P 

+  2.3 
-I.223 

+  2.0 
O 

10.38 
10 
3 
3 
9.06 

9.06 
9.06 

10 

8 
10.53 

10 

7-34 

12.8 

7-4 
7-4 
7-3 

7-3 

7-3 
7-3 

7-3 

10 
10 

400 

Fischer5 
Vignon6 
Fischer7 

14 

v.  Lippmann8 
(  Fischer  and 

\       "     Stahel9 

«          « 

Fischer10 
f  Fischer  and 
X  Passmore11 
Fischer12 

t<         13 

.0 

+  22.5 
•f  28.3 
-28.3 
4-  1.5 

-f  1.4 

•  M 
-  5.5 

+  4-8 

-f-  6.0 

+  2.6 

d-          " 

/.          «           

//-Sorhitol 

d-         " 

/.          "        

</-Talitol  

a-Mannoheptitol  ^ 
(Perseit)           j 

/3-Methylgalactoside 

In  ordinary  ^-mannitol  dissolved  in  water  Vignon,14  Miintz 
and  Aubin,15and  others  could  find  no  activity,  but  Bouchardat,1' 

Bouchardat :  Compt.  rend.,  80,  120:  Jahresbericht,  (1875),  p.  145. 

Gernez  :  Compt.  rend.,  113,  1031. 

Gernez  :  Ibid.,  114,480. 

Amount  in  a  borax  solution  saturated  at  the  ordinary  temperature. 

Fischer  :  Ber.  d.  chem.  Ges.,  34,  538. 

Vignon  :  Compt.  rend.,  77,  1191  (1873)  ;  Ann.  chim.  phys.,  [5],  3,  440  (1874). 

Fischer:  Ber.  d.  chem.  Ges.,  33,  385. 

v.  Lippmann  :  Ibid.,  35,  3220. 

Fischer  and  Stahel :  Ibid.,  24,  2144. 

Fischer  :  Ibid.,  37,  1528. 

11  Fischer  and  Passmore  :  Ibid.,  33,  2232. 

12  Fischer  :  Ann.  Chem.  (I,iebig),  370,  99. 
18  Fischer  :  Ber.  d.  chem.  Ges.,  38,  1155. 

14  Vignon :  Loc.  cit. 

1    Miintz  and  Aubin  :  Ann.  chim.  phys.,  [5],  10,  533. 

16  Bouchardat  :  Compt.  rend.,  80,  120. 


PRESENCE    OF    INACTIVE    BODIES  2.55 

on  the  other  hand,  with  a  tube  three  meters  in  length  filled 
with  a  solution  of  c=  15,  found  by  aid  of  a  half-shadow 
apparatus  and  sodium  light  a  rotation  aD  =  —  i°  8',  from 
which  \_<x]D  =  —  0.25°.  Under  similar  conditions  it  is  likely 
that  rotating  power  would  be  found  in  solutions  of  other  bodies 
of  the  mannitol  group. 

The  chemical  action  of  borax  on  the  compounds  of  the 
mannitol  group  does  not  consist  in  the  formation  of  simple 
addition  products.  It  is  known  that  not  only  these  varieties 
of  sugars  but  also  the  glucoses,  as  grape-sugar,  galactose, 
fructose,  and  even  glycol  and  glycerol  on  addition  of  borax, 
which  in  itself  has  an  alkaline  reaction,  yield  strongly  acid 
solutions  and  this  is  also  the  case  when  sodium  bicarbonate 
(but  not  the  mono-carbonate)  is  likewise  present  (Dunstan,1 
Klein,2  Lambert,3  Donath, 4  Jehn).5 

It  appears  that,  as  with  the  oxyacids  (tartaric  acid),  bodies 
of  acid  character  containing  boron  are  formed,  which,  in  con- 
sequence of  the  reaction  of  two  hydroxyl  groups  on  one  mole- 
cule of  boric  acid,  contain  the  cyclic  complex 
C-(X 

>B— O— H  (van't  Hoff).6 
C— <Y 

If  free  boric  acid  is  added  to  mannitol  the  two  unite  in  the 
proportion  of  3  molecules  of  acid  to  i  of  mannitol,  as  Mag- 
nanini7  found  by  observations  on  the  electric  conductivity  of 
their  solutions. 

The  sugars,  which  from  their  constitution  should  be  inactive, 
do  not  become  active  by  addition  of  borax,  which  has  been 
shown  for  dulcitol  (Crossley),8  xylitol  (Fischer),9  adonitol 
(Fischer),10  and  tf-glucoheptitol  (Fischer).11 

Other  bodies  also  besides  borax  have  the  power  to  call  out 
the  activity  of  mannitol.  Thus,  right  rotation  is  produced  by 

1  Dunstan:  Ber.  d.  chem.  Ges.,  16,  2504  Ref. 

*  Klein:  Compt.  rend.,  99,  144;  Bull.  Soc.  Chim.  [2],  29,  198,  357.     It  is  said  that  the 
barium  salt,  (CeHjaOs^BaO^B^,  can  be  made. 

3  Lambert:  Compt.  rend.,  108,  1016. 

*  Donath:  Chem.  Ztg.,  17,  1826. 

5  Jehn:  Arch.  Pharm.,  25,  250;  26,  495. 

''  van't  Hoff:  Lagerung  der  Atome  in  Raume,  2nd  ed.,  p.  113. 

~  Magnanini:  Ztschr.  phys.  Chem.,  6,  66. 

*  Crossley:  Ber.  d.  chem.  Ges.,  25,  2564. 
-'  Fischer:  Ibid.,  24,  528. 

111  Fischer:  Ibid.^  26,  634. 

11  Fischer:  Ann.  Chem.  (lyiebig),  270,  81. 


SPECIFIC    ROTATION 


arsenic  acid,  neutral  sodium  arsenate  (Vignon),1  tungstates 
(Klein).2  Left  rotation  is  produced  by  alkalies,  alkali  carbon- 
ates, acid  sodium  arsenate  and  alkali-earths  (Vignon). 

d.  Action  of  Acid  Sodium  and  Ammonium  Molybdate  on 
Mannitol)  Sorbitol,  a-Mannoheptitol  {Perseit)  and  Rhamnose 
(Isodulcitol) . — The  three  sugars  named  first,  which  in  pure 
aqueous  solution  possess  a  slight  rotation  to  the  left,  are  not 
influenced  by  neutral  molybdates;  on  the  other  hand  free 
molybdic  acid  and  its  acid  salts  produce  in  these  solutions 
strong  dextrorotation.  Gernez  added  the  molybdates, 

Na6Mo.O24  +  22H2O  and  (NH4)6Mo7O24  -f  4H2O, 
in  increasing  amounts  ( a1?  to  above  I?  of  the  molecular  weight 
to  i  mol.  of  sugar)  and  found  that  the  right  rotation  increases  to 
a  maximum  and  then  decreases.  The  largest  values  for  mannitol, 
sorbitol  and  mannoheptitol,  were  found  when  the  solutions 
contained  for  one  molecule  of  these  bodies  6j\5  —  0.28  mole- 
cule of  the  sodium  or  ammonium  molybdate.  The  following 
specific  rotations  are  calculated  from  the  data  of  Gernez.3 


Rotation 

Maximum  rotation. 

Sugar 
in  100  cc. 
solution. 

Temp. 

of  the  pure 
aqueous 
solution. 

With  6il8  me 
Na  salt. 

1.  salt  added 
NH4  salt. 

rf-Mannitol  - 

3.160 

17° 

-0.26° 

+  43.I90 

+  43.I90 

^-Sorbitol  .  . 

6.548 

17 

—  2.04 

+  41.87 

+  4L48 

rf-Perseit  .  .  . 

7.36I4 

15 

—  1.22 

+  48.77 

+  48.90 

The  behavior  of  rhamnose  is  somewhat  different.5  This 
body  shows  immediately  after  solution  in  water  a  rotation  to 
the  left,  then  after  some  hours  a  constant  right  rotation  which 
has,  for  c=  6.319,  the  value  [«]/!  =  +  9-75°.  This  last  is 
increased  by  addition  of  sodium  or  ammonium  molybdate  until 
the  salt  added  amounts  to  Q?V  molecule  for  each  molecule  of 
rhamnose,  and  then  remains  unchanged  with  further  addition 

1  Vijjnon:  Ann.  chim.  phys.,  [5],  a,  433. 

2  Klein:  Compt.  rend.,  89,  484. 

8  Gernez:  Mannitol,  Compt.  rend.,  112,1360.  In  this  paper  the  maximum  of  rotation 
is  given  for  e8i8  molecule  of  the  salt,  although  the  half  weight  of  the  above  formula 
appears  to  have  been  taken.  Sorbitol,  Compt.  rend.,  113,  1031;  Perseit,  Ibid.,  114,4*0. 

4  Superaturated . 

5  Gernez:  Rhamnose,  Compt.  rend.,  119,  63. 


MULTIROTATIOX  257 

of    the    salts.     The   observed    constant    maximum     rotation 
amounts  to 


[«]*  22.95°,  for 

[flfjg  =  +  19-91°,  for 


the  sodium  salt, 
the  ammonium  salt. 


A  satisfactory  explanation  for  the  occurrence  of  the  number 
60745  is  wanting.  Possibly,  as  with  borax,  the  molybdenum 
enters  the  sugar  molecule. 

F.  Multirotation. 

With  a  number  of  active  substances  the  phenomenon  is 
observed  that  the  rotating  power  of  a  freshly  prepared  solution 
changes  on  standing,  undergoing  either  an  increase  or  decrease 
until  finally  a  constant  value  is  reached.  This  behavior  is 
shown  by: 

1 .  A  number  of  the  sugars. 

2.  Certain  oxy-salts  and  their  lactones. 

3.  A  few  other  substances. 

/.   JHultirotation  of  the  Sugars. 

71.  Preliminary  Remarks. — In  1846  Dubrunfaut1  made  the 
observation  that  the  rotation  of  an  aqueous  grape-sugar  solu- 
tion, prepared  at  the  ordinary  temperature,  decreased  to  a  cer- 
tain limit  on  standing.  The  same  behavior  was  noted  in  1850 
by  Pasteur2  in  a  grape-sugar-sodium  chloride  solution,  and  this 
chemist  established  the  fact  that  the  beginning  rotation  is 
about  twice  as  great  as  the  final  constant  rotation,  a  condition 
which  E.  O.  Erdmann3  in  1855  and  Dubrunfaut4  in  1856  veri- 
fied with  grape-sugar.  The  high  beginning  rotation  was,  there- 
fore, designated  as  birotation. 

The  phenomenon  of  decrease  in  rotation  was  noted  by 
Erdmann  in  ordinary  milk-sugar,  and  later  the  same  behavior 
has  been  observed  by  Tollens  and  E.  Fischer  in  many  other 
varieties  of  sugars.  It  has  been  recognized,  however,  that  the 
relation  of  the  beginning  to  the  final  rotation  is  not  always  2:1, 
as  with  dextrose,  but  may  be  1.6  :  i  as  in  the  case  of  milk- 
sugar,  or  1.46  :  i  as  with  galactose  or  4.67  :  i  as  observed  with 

1  Dubrunfaut:  Compt.  rend.,  23,  42. 
'-'  Pasteur:  Ann.  chim.  phys.,  [3],  31,  95. 
8  Erdmann:  Jahresbericht,  (1855),  p.  671. 
4  Dubrunfaut:  Compt.  rend.,  42,  22^. 

17 


258  SPECIFIC    ROTATION 

xylose.  Because  of  this  it  was  suggested  by  Wheeler  and 
Tollens1  in  1889  to  change  the  first  designation,  birotation,  into 
mnltirotation. 

It  was  further  observed  by  Schmoger  in  1880  and  also  by 
E.  O.  Erdmann  that  milk-sugar  on  dehydration  changes  into 
a  modification  which  on  re-solution  shows  a  gradual  increase  in 
rotation  and  the  same  behavior  was  found  with  maltose  by 
Meissl4  in  1882.  Schmoger  describes  this  low  rotation  as 
half  rotation.  The  terms  greater  rotation  (Mehrdrehung)  and 
less  rotation  (Wenigerdrehung)  were  later  introduced  by  Parcus 
and  Tollens'  to  describe  the  two  kinds  of  rotation. 

A  further  advance  was  made  in  1895  by  Tanret  who  found 
that  in  certain  sugars,  besides  the  known  modifications,  a  and 
ft,  of  which  the  higher  rotating,  a,  is  transformed  after  solution 
into  ft,  a  third  modification,  7,  may  be  obtained  which  in 
solution  is  likewise  transformed  into  ft.  This  is  the  case  in 
the  following  bodies,  the  three  forms  of  which  with  respect  to 
their  specific  rotations,  for],,,  stand  in  the  following  order, 


Modification. 


a 

(labile). 

(stable). 

(labile). 

^/-Glucose  .... 

~o 

*/-Galactose«  • 

*  °5 

Q, 

-    22.5° 

Milk-sugar  

J35 

QC 

-x»     i      _/r 

1     x*  i 

•    55 

V.  T  3" 

The  form  or  show*  ^reater  rotation  and  ;/  less  rotation  ; 
there  is  then  by  the  change  of  (if  into  ft  a  decrease  and,  on  the 
other  hand,  by  the  change  of  ;/  into  ft  an  increase  in  the 
rotation. 

The  conditions  with  rhamnose  are  different. 

Modification  a  0  y 

Rhamnose  ...............  6°  go  ;        0 

Here  we  find  by  the  conversion  of  a  into  ft,  first  a  decrease 
in  the  negative  rotation,  and  then  after  passing  a  certain  point 

T  and  Tollrns    Ann    Chcm    (I.iehix  >,  254 
»  Schmdger  ,  <    ,9IS 

•iann    Her   <1   cliein    <,,  .     M 

•  Mei-1:  J.  prmkt.  Chem..  fa].  J8, 

*  Pircun  and  Tollt  o    aS7    „,, 


SUGARS    SHOWING    MULTIROTATION  259 

of  inactivity,  an  increase  in  the  right-hand  rotation,  while  the 
change  of  y  into  ft  is  accompanied  by  a  decrease  in  rotation. 
The  preparation  of  the  three  modifications  of  the  above  sugars 
is  given  in  §  72. 

The  rapidity  with  which  a  labile  modification  of  a  sugar 
changes  into  the  stable  form,  increases  in  marked  degree  with 
rise  in  temperature.  At  the  ordinary  temperature  a  period  of 
from  six  to  twenty-four  hours  is  usually  required,  but  by  boil- 
ing, the  transformation  is  completed  in  a  few  minutes.  This 
behavior  was  observed  by  Dubrunfaut  with  grape-sugar  and 
with  milk-sugar. 

After  solution  of  a  labile  sugar  form  in  water  the  change 
begins  immediately  and  it  is  not,  therefore,  possible  to  estab- 
lish the  beginning  rotation  with  accuracy.  Several  minutes 
must  elapse  before  the  observation  of  the  liquid  in  the  polari- 
scope  can  commence,  and  with  the  greater  rotating  or-forms  a 
value  somewhat  too  low  and  with  the  lower  rotating  y-forms  a 
value  somewhat  too  high  is  always  found.  An  accurate  result 
is  obtained  only  for  the  end  product  of  the  transformation,  the 
stable  /?- modification. 

72.  Resume  of  the  Sugars  Showing  Multirotation. — The  follow- 
ing observations  were  all  carried  out  by  allowing  the  transfor- 
mation to  proceed  at  the  ordinary  temperature  (usually  20°). 
First,  in  the  shortest  possible  time  after  preparation  of  the 
solutions,  the  beginning  rotation  was  determined  and  later  the 
constant  end  rotation,  the  time  required  to  complete  the  change 
being  noted.  The  specific  rotations  given  correspond  to  [<*]  />, 
and  the  concentration,  c,  expresses  the  number  of  grams  of 
sugar  in  100  cc.  of  solution.1 

i.  l-Arabinose,  C.H10O5  (two  modifications) 

a- Modification. — Ordinary  crystallized  arabinose. 
ft- Modification. — This   is   obtained   by   precipitating    a  hot 
solution  of  the  tf-form  in  an  equal  weight  of  water,  by  addition 
of  20  parts  of  absolute  alcohol.     In  the  crystallized  condition 
it  is  not  stable  and  reverts  gradually  to  the  <*-form.J 

1  Many  of  the  data  based  on  density  and  percentage   composition    have    been 
reduced  to  this  form  to  correspond. 

-  Tanret:  Bull.  Soc.  Chim.,  [3],  15,  201. 


260  SPECIFIC    ROTATION 

Observed  for  c       9.73,  t  =  20° 

a.   First  rotation  after  6.5  minutes 4-156.7°   1  Decrease 

ft.   Final  rotation  after  1 .5  hours +  104.6° l  /     52- l0 

ft.  (c=  13.8)  +  105°.     (c  -  2.5)   +  104°  (Tanret). 

2.  l-Xylose,  C5H10O5  (two  modifications) 
a- Modification,  ordinary  xylose. 

ft- Modification,  not  yet  obtained  pure,  but  mixed  with  «  ; 
reverts  to  a  in  solid  condition. 

Observation  i.     c  =  10.235,  *       20° 

a.   First  rotation  after  5  minutes -    85.9°   )  Decrease 

ft.  Final  rotation  after  5  hours •    18.6°  -  )      67-3° 

Observation  2.     c  -     1 1.07,  /    -  20 

a.   First  rotation  after  4.5  minutes -J    78.6°   \  Decrease 

ft.  Final  rotation  after  2.5  hours I9.2°:!)     59-4° 

3.  d-Glucose,  C,.H,2O6  (three  modifications) 

a- Modification. — Ordinary  form  crystallized  from  water  at 
mean  room  temperature  as  hydrate,  C^H^O,.  +  H2O,  or  as 
anhydrous  crystallized  grape-sugar  from  alcohol  or  from  water 
at  30°  to  35°.  Immediately  after  solution,  and  referred  to  the 
anhydride,  [<*]/>>  -f-  105°,  then  by  change  into  /?,  decreases 
to  52.5. 

ft- Modification. — This  remains  usually  as  an  amorphous 
hygroscopic  mass  by  evaporation  of  dissolved  «- glucose.  It 
may  be  obtained  in  crystalline  condition  by  evaporating  on  the 
water-bath,  and  stirring  constantly,  dissolving  the  residue 
dried  at  98°  in  half  its  weight  of  cold  water  and  adding  a  large 
amount  of  alcohol  cooled  to  o°  ;  or  it  may  be  made  by  melt- 
ing ar-glucose,  cooling  to  100°  and  adding  some  crystals  of 
/?•  glucose.  It  dissolves  at  19°  in  half  its  weight  of  water  and 
shows  the  con-tant  rotation  of  -f-  52.5°  (referred  to  C6HI2O6). 
On  evaporation  of  its  aqueous  solution  it  yields  «-glucose, 
which,  however,  is  only  formed  after,  crystallization,  as  the 
mother-liquor  slmw^  alway^  the  rotation  of  p.* 

The  y-Modification  is  formed   when  a  concentrated  solution 

ircusand  Tollenn:  Ann.  Chcm    (i,irt>ig),  357,  174. 
*  Wheeler  and  Tollcns:  Ann.  Chcm.  (I.iebin),  254,311. 
»  Parcus and  Tollen*    Ann   Chnn   (l.icbiK),  257,  175. 

«  According  to  Lobry  de  Bruyti  ;m.i  \lh,-r.|.i  van  l-:k»-n>.trin  HIT.  <I.  chcin.(.<v, 
3H. 


SUGARS    SHOWING    MULTIROTATIOX  26l 

of  <*- glucose  is  evaporated  and  the  residue  heated  for  several 
hours  to  no0.  The  mass,  which  consists  of  ft  and  y,  is  dis- 
solved in  an  equal  weight  of  water  and  treated  with  a  large 
volume  of  alcohol  which  precipitates  the  y-form  first.  This 
form  separates  first  also  by  recrystallizing  from  alcohol.  It 
requires  for  solution  at  19°,  three-fourths  of  its  weight  of 
water  and  shows  a  beginning  rotation  of  -f-  22.5°  (for  C6H12O^) 
which,  in  consequence  of  change  to  the  /^-modification  increases 
gradually  to  52.50.1 

The  three  forms  exhibit  the  same  depression  of  the  freezing- 
point. 

Change  of  ct  into  /3. 

1.  c  =  9.097,  /  =  20°. 

a  First  rotation  after  5.5  minutes -f  105.2°     1    Decrease 

/3  Final  rotation  after  6  hours -f-    52.5°     /        52-7° 

2.  c  =  5.526,  /  =  20°. 

a  First  rotation  after  7  minutes -f-  104.3°    \    Decrease 

/3  Final  rotation  after  7  hours -f    52. 6° 2  J        5i-7° 

Change  of  y  into  /3. 

y  First  rotation  (Tanret) -j-    22.5°    •»    Increase 

ft  Final  rotation -f    52.5°    J       3Q.o° 

4.  d- Glucose  Sodium  Chloride,  2  C6H,.,O6  -f-  NaCl  (two  modifica- 

tions) 

c  =  10.46,  containing  0,90  C6H,2O6. 

First  rotation  after  15  minutes  (for  C6H12O6).  -f    99-4°    \    Decrease 

Final  rotation  after  20  hours -f-    50.3°  3  J       49- J  ° 

5.  d-Glucoseoxime,  C6H12O5.NOH  (two  modifications) 
(c  =  9.648) 

First  rotation  after  15  minutes —    5.4°       •»    Decrease 

Final  rotation  after  1 8  hours --    2.2°*    J        3-2° 

6.  d-Glucosephenylhydrazone,    C6H,.,O5.N.,H.C6H5    (two   modi- 

fications) 

First  rotation  after  10  minutes —  15-3°     \     Increase 

Final  rotation  after  12-15  hours —  46.9°  5  /       31-60 

1  Tanret :  Compt.  rend.,  130,  1060. 

-  Parcus  and  Tollens':  Ann.  Chem.  (Liebig),  357,  164. 

3  Trey  :  Ztschr.  phys.  Chem.,  32,  428. 

4  Jacobi  :  Her.  d.  chem.  Ges.,  34,  697. 

5  Jacobi  :  Ann.  Chem.  (I.iebig),  373,  173. 


262  SPECIFIC    ROTATION 

7.  l-Glucose,  C6H,,O,5  (two  modifications) 


First  rotation  after  7  minutes  ...............   --    94.5°    •>    Decrease 

Final  rotation  after  7  hours  .................          51.  401  /       43-  x° 

8.  d-Galadose,  C6H,2O6  (three  modifications) 
a-  Modification.  —  Ordinary  crystallized  galactose. 

*  ft-  Modification.  —  This  is  obtained  by  dissolving  the  a-  form 
in  i^  to  2  parts  of  boiling  water  and  pouring  the 
solution  into  eight  times  the  volume  of  alcohol,  stirring  mean- 
while, which  produces  a  crystalline  precipitate.  The  conver- 
sion of  a  into  ft  is  complete  in  strong  solution  only.  It  is  sol- 
uble in  1.57  parts  of  water  at  22°,  and  reverts  into  the  a-  form 
on  crystallization  from  water. 

The  y-  Modification  is  said  to  be  produced  when  a  solution  of 
12  grams  of  or-galactose  in  30  grams  of  water  is  treated  with 
0.03  gram  of  sodium  phosphate  and  a  drop  of  dilute  sulphuric 
acid,  warmed  on  the  water-bath  a  few  minutes,  then  cooled,  and 
gradually  mixed  with  240  cc.  of  absolute  alcohol.  On  repeat- 
ing the  process  several  times  the  rotation  of  the  product,  prob- 
ably still  impure,  could  be  reduced  to  52.25°.  In  aqueous 
solution  at  the  ordinary  temperature  it  is  converted  into  ft 
inside  of  two  hours,  while  for  conversion  into  ct  three  times  as 
long  is  required.' 

Change  of  a  into  ft. 
(c       10) 

a  First  rotation  after  7  minutes  ..............  -j    1  1  7.4°  )  Decrease 

ft  Final  rotation  after  6  hours  .................  +    80.3°'  /     37-lQ 

o  First  rotation  (Tanret)  .....................  l35-°°  \  Decrease 

ft  Final  rotation         "          ..............    85.3+    81.6°  »       53-4 

Change  of  7  into  ft. 

',  First  rotation  after  5  minutes  (Tanret)  ......  52-3°  \  Increase 

ft  Final  rotation  (Tanret)  ..............  •  ......  81.6°  J     29-3° 

9.  d-Galactoseoxime  ,  C6H12O3.NOH  (two  modifications). 

5-217) 
First  rotation  after  10  minutes  ...............  20.6°    }  Decrease 

Final  rotation  after  20  hours  .................  14.  5°4 

1  E.  Fischer  :  Ber.  d.  chem.  C.es.,  33,  2619. 

-  Tanret  :  Bull.  Soc.  Chim.,  [3],  15,  195. 

*  Parcus  and  Tollens:  Ann.  Chem.  (Liebig),  257,  169. 
4  Jacobi:  Ber.  d.  chem.  Ges.,  24,  698. 


SrciARS    SHOWING    MULTIROTATIOX  263 

10.  d-Mannoseoxime,  C6HlviO..NOH  (two  modifications) 

(c  =  4.875) 

First  rotation  after  io  minutes —      7.5°    )  Decrease 

Final  rotation  after  6  hours -        3.2°' /      4-3° 

11.  d-Fructose,  Levulose,  C6H,.,O6 

C          10,  /          20°. 

First  rotation  after  6  minutes —  104.0°    \  Decrease 

Final  rotation  after  20  to  25  minutes -    92. 3°2  J      Il-7° 

Final  rotation 90.2°* 

Final  rotation -  -    90. 7°* 

12.  Rhamnose,     isodulcite,     C6H12O5;   hydrate,    C^H^O^   (three 

modifications) 

a- Modification. — Ordinary  rhamnose,  crystallized  from  water. 

As  hydrate  dissolved  in  water  it  shows  a  beginning  rotation  of 

-  5°  to  —  7°  (referred  to  C6H,.,O3),  then,  by  conversion  into 

the  /3-form,  a  decrease  and  afterwards  a  change  to  increasing 

right  rotation  which  reaches  about  -(-10°. 

ft- Modification. — For  the  preparation  of  this  i  part  of  the 
a -form  is  dissolved  in  ^  part  of  boiling  water  and  then  mixed 
with  5  parts  of  absolute  alcohol  and  5  parts  of  ether.  The 
first  crystalline  precipitate  which  separates  is  ^-rhamnose; 
this  is  removed  and  a  new  portion  of  ether  is  added,  which 
throws  down  the  /3-form,  with  which,  however,  a  small  amount 
of  the  y-iorm  with  lower  rotation  may  be  mixed.  The  (3- form 
crystallizes  with  J  molecule  of  water  in  fine  needles.  It 
attracts  moisture  from  the  air  and  reverts  into  the  tf-form.  In 
aqueous  solution  it  shows  the  constant  right  rotation  of  -(-9.1° 
to  10.1°  or  even  12.7°,  referred  to  CBH12O5.:> 

y- Modification. — This  is  produced  from  the  /^-rhamnose 
when  it  is  dried  in  a  desiccator,  and  then  heated  for  several 
hours  to  90°.  On  crystallizing,  it  reverts  to  the  tf-form.  It 
begins  with  a  rotation  of  -f  22.8°,  which  gradually  sinks  to 
about  -j-  10°  through  conversion  into  the  y#-form.6 

1  Jacobi:  Ber.  d   chem.  Ges.,  24,  699. 
Parcus  and  Tollens:  Ann.  Chem.  (Liebig),  257,  166. 
Jungfleisch  and  Grimbert:  Compt.  rend.,  107,  390. 
Honig  and  Jesser:  Wien.  Akad.,  Ber.,  97,  II,  547. 
Tanret:  Bull.  Soc.  Chim..  (3),  15,  202. 
Tan  ret  :  I.oc.  cit. 


264  SPECIFIC    ROTATION 

Change  of  a  into  /3. 
Hydrate  dissolved  in  water.     Calculated  for  C6Hi2O5. 

1.  c  —  io,  /—  20°. 

a  First  rotation  after  5.5  minutes —  5°      ->  Decrease  and 

}  Final  rotation  after  66  minutes -f  9-4cl  J  increase  14.4° 

2.  c  -----  9.08,  ordinary  temperature. 

a  First  rotation  after  i    minute —  5.6°  "i  Decrease  and 

ft  Final  rotation  after  i    hour -f  9-2°"'  /  increase  14.8° 

3.  c  —  5  and  io,  /       13.5°. 

a  First  rotation  after    10.5   minutes —  7.1°  |  Decrease  and 

/9  Final  rotation  after  i    hour -f  9.I03  J  increase  16.2° 

Rhamnose  anhydride  dissolved  in  water  (c=  9.5)  shows  at 
once  the  constant  rotation  -f-  8.7   (/?-form).4 
Change  of  y  into  /3. 


7  First  rotation •    22. 8C  )  Decrease 


/3  Final  rotation  after  1.5  hours •    10.1° 

With  alcohol  as  solvent  different  rotations  are  found.  Jacobi 
(loc.  tit.)  gives  the  following  observations: 

1.  Hydrate,  dissolved  in  alcohol,  C—   7.67. 

First  rotation,  after  15  minutes  (for  C6H12O5)    —  12.6°  ^  Decrease 
Final  rotation  after  16  hours       "          "  -  10.0°  /     2.6° 

2.  Anhydride  dissolved  in  alcohol,  c—  7.5. 

First  rotation  after  5  minutes  (for  C6H12O5) . .   ^  3.4°  1  Decrease  and 
Final  rotation  after  24  hours       "         "         •.   —  9.0° /increase  12.4° 

For  the  explanation  of  the  phenomenon  that  the  hydrate 
and  anhydride  of  rhamnose  show  a  rotation  in  alcohol  opposed 
to  that  in  water  see  §  64. 

13.        Rhamnoseoxime •,  CBH,.,O4.NOH  (two  modifications) 
c       9.863,  ordinary  temperature. 

First  rotation  after  io  minutes f  6.  i °     )  increase 

Final  rotation  after  20  hours -f  13.6° 5  /      7.5° 

14-  Fucose,  C6H12O5  (two  modifications) 

6.916,  /         20°. 

I ;irst  rotation  after  ir   minutes -111.8°   )  Decrease 

Final  rotation  after  2  hours -  77.0°*  f       34.8° 

1  Schnelle  and  Tollens  :  Ann.  Chem.  (I^iebij?),  371,  63. 
-  Jacobi  :  Ann.  Chem.  (IJebig),  ajj,  176. 

Tan  ret  :  I.»c.  at. 

4  Jacobi  :  Ann.  Cht-in.  (Ut-bix),  »7»,  177. 
•'•  Jacobi:  Her.  d.  chrm    <  .<-     24,  698. 

(.iinther  and  Tollens:  Ann.  Chem    (I.iebijf),  371,90. 


SUGARS    SHOWING    MUI/TIROTATION  265 

15.  RhamnohexosC)  C.H,^  (two  modifications) 

t  10,   /  2 

First  rotation  after  \  hour  .................  —  82.9°    ^  Decrease 

Final  rotation  after  12  hours  ................  —  61.4°  !  j'      21.5° 

1  6.  d-Mannoheptose,  CTH14O.  (two  modifications) 

c=  10.  14  ordinary  temperature. 
First  rotation   after  lominutes   ..............  -{-  85.  i°    )  Decrease 

Final  rotation    after  24  hours  ................  -\   68.6°  -  i       16.5° 

17.  ct-Glucoheptose,  C.H14O.  (two  modifications) 


c 
First  rotation  after  15  minutes  ..............    —  25.0-     )  Decrease 

Final  rotation  after  some  hours  .............  —  I9-7°3  f      5-3° 

1  8.       a-Glucoctose,  CsH16Ob  -j-  2  H2O  (two  modifications) 

c  =  6.637,  dissolved  at  50°  and  cooled. 
First  rotation  ..............................  —  6  1  .4-   )  Decrease 

Final  rotation  after  6  hours  .................  —  43  9°  4  j      17.5° 

19.  Milk-sugar,  C^H^O,,  (three  modifications) 

a-  Modification.  —  Ordinary  crystallized  milk-sugar,  C12H22On-f- 
H.,O.  This  exhibits  a  beginning  rotation  of  -j-  87°  (anhydrous) 
and  in  aqueous  solution  is  changed  into  the  /3-form.  ' 

ft-  Modification.  —  This  may  be  obtained  from  a  and  /?,  and  is 
secured  in  crystalline  form,  C12H22On  -f  1/2  H2O,  by  adding 
three  or  four  volumes  of  absolute  alcohol  to  the  warm  concen- 
trated solution  of  either  of  these.6 

The  ^-form  is  obtained  by  rapidly  evaporating  a  solution  of 
two  or  three  grams  of  tf-milk-sugar  in  10  cc.  of  water  to  dry- 
ness  in  a  platinum-dish  on  a  water-bath,  and  drying  the  resi- 
due at  98°  to  complete  loss  of  the  water  of  crystallization.7 
It  may  also  be  obtained  by  rapidly  boiling  down  a  solution  of 
ordinary  milk-sugar  in  a  metallic  vessel,  when  suddenly  the 
whole  liquid  solidifies  to  a  mass  of  small  porous  anhydrous 
crystals/  Pure  anhydrous  crystals  may  be  secured  by  repeated 

1  Fischer  and  Piloty:  Ber.  d.  chem.  Ges.,  33,  3102. 

-  Fischer  and  Passmore:  Ber.  d.  chem.  Ges.,  23,  2230. 

3  Fischer:  Ann.  Chem.  (Liebig),  379,  75. 

4  Fischer:  Ann.  Chem.  (Liebig),  270,  97. 

*  Erdmann  and  Schmoger  :  Ber.  d.  chem.  Ges.,  13,  1922. 
fi  Tanret:  Bull.  Soc.Chim.,  (3),  13,  625. 

•  Schmoger  :  Ber.  d.  chem.  Ges.,  13,  1915- 

-  Erdmann  :  Ber.  d.  chem.  Ges.,  13,  2180. 


266  SPECIFIC    ROTATION 

crystallization  from  anhydrous  alcohol    (Tanret).     The  first 
rotation  is  +36.2°,  which  increases  to  that  of  the  /f-form. 

The  three  forms  show  the  same  freezing-point  depression. 

If  ordinary   powdered  milk-sugar  is  dehydrated  at   130°,  the 
residue  shows  the  rotation  phenomena  of  the  or-form. 
Change  of  a  into  ft 

I-  c  '---'-  7-5  (hydrate),  /  =  20°. 

Calculated  for 


a  First  rotation   after  4  minutes  ..    +84.0  88.4°   \  Decrease 

0  Final  rotation  after  6  hours  ----   -   52.5  55-3°'  *  33-lD 

2.  £^4.841  (hydrate).     /  =  20° 

a  First  rotation    after  8  minutes.      4  82.9°  -|-    87.3°^  Decrease 

/3  Final  rotation  after  24  hours..    -\   52.5  55-3°"  '  32.0° 

Change  of  y  into  /3. 
c  =  7.07  ;  7.72  ;  ordinary  temperature. 

y  First  rotation  .................   -•   34.4°  -f    36-2°  1  Increase 

/3  Final  rotation  after  24  hours  ...   4  52.45  -j-  55.2°'  )  19.0° 

20.         Maltose,  C12H2aOu  (two  modifications)  ;  hydrate, 
'  ClrHB0,,  +  H20 

1.  c  ••--  14  to  19  (anhydride)    /  =  15°. 

forCkAfti- 

First  rotation  after    4  minutes...    -f  122.0     to    124.8°  \  Increase 

Final  rotation  after  12  hours  .........       -f   138.  3°*  >'  13.5° 

2.  c  =  9.2  to  9.8  (anhydride),  /  ~  20°. 

First  rotation  after  6  to  12  minutes        118.8   to    121.0°   ^  Increase 

Final  rotation  after  5  to    9  hours            136.8   to    137.  o05  J  17.0° 

The  absence  of  multirotation  has  been  shown  for  inosite, 
sorbin,  levosin,  ethyl  glucoside,  methyl  and  ethyl  galactosides, 
benzyl  arabinoside,  and  the  phenyl  hydrazonesof  galactose  and 
rhamnose. 

73.  Rate  of  Change  in  Rotation.  —  Urech5  was  the  first  to  show 
that  the  Wilhelmy  velocity  formula  for  reactions  of  the  first 
order, 


Schmoger  :  Ber.  d.  chem.  Ges.,  13,  1931. 

Parcus  and  Tollens  .  Ann.  Chem.  (Liebig),  357,  170. 

Schmoger  :  Ber.  d.  chem.  C.es.,  13,  1918. 

Meissl  :  J.  prakt.  Chem.,  (2)  35,  122. 

Parcus  and  Tollens  :  Ann.  Chem.  (Uiebig),  357,  172. 

I'rech  :  Ber.  d.  chem.  Ges.,  16,  II,  2270  (1883)  ;  17,  I,  1547;  18,  II,  3059. 


RATE    OF    CHANGE    OF    ROTATION 


267 


is  applicable  to  the  case  of  the  change  of  rotation  in  milk-sugar 
and  grape-sugar.  New  and  careful  investigations  with  refer- 
ence to  dextrose  have  been  carried  out  by  Levy1  and  by 
Trey.'  In  consideration  of  the  fact  that  the  actual  beginning 
rotation  is  a  quantity  which  can  never  be  accurately  deter- 
mined here,  the  first  of  these  observers  changed  the  formula 
used  in  calculating  the  constant,  C, 


(I) 


into 


(II) 


in  which  fifi.,  are  the  rotations  corresponding  to  the  times  /,/2, 
and  (f)  represents  the  constant  final  rotation.3 

In  illustration  the  following  series  of  observations  by  Levy 
may  be  given : 

AQUEOUS    SOLUTION  OF  ANHYDROUS    DEXTROSE    OF  3.502  PER  CENT 
STRENGTH  d™~  1.0114,  TEMPERATURE,  20.5°  TO  20.9°.  • 


Time  in  minutes 
after  solution. 

Observed  angle 
of  rotation 
/  =  S  dm. 

t»  —  /t. 

Temperature. 

!    Constant  C. 
<     formula  II. 

1       . 

/,  =  25 

ft         27.865° 

0 

20.9° 

t,  =  30 

ft         27.060 

5 

20.9 

0.00649 

',  =  35 

ft  =  26.159 

10 

20.9 

0.00719 

A,  =  40 

ft         25.637 

15 

20.8 

0.00644 

>,•       45 

ft  =  24.927 

20 

20.7 

0.00662 

/,.       50 

ft  =  24.369 

25 

20.6 

0.00652 

*i       55 

ft  =  23-895 

3° 

20.5 

0.00636 

/,       60 

ft  =  23.166 

35 

20.5 

0.00677 

65 

ft  =  22.797 

40 

20.5 

0.00656 

t,  =  70 

ft-    22.171 

45 

20.5 

0.00687 

t-i  =  75 

ft  =  21.837 

50 

20.5 

0.00674 

t.       So 

ft       21.470 

55 

20.5 

0.00671 

>,  =  85 

ft  =    21.088 

60 

20.5 

0.00675 

24  hours 

0              16.692 

Mean 

0.00662 

1  l,evy  :  Ztschr.  phys.  Chem.,  17,  301   (1895). 

2  Trey  :  Ibid.,  18,  193.;  23,  424. 

1  The  same  formula  was  derived  somewhat  earlier  by  P.  Th.  Miiller:  Compt.  rend., 
118,  425. 


268 


SPECIFIC    ROTATION 


From  fifteen  series  of  experiments  made  at  a  nearly  constant 
temperature  of  20°,  Levy  found  that  for  strengths  of  i  to  5 
per  cent.,  the  constant,  C,  is  independent  of  the  concentration. 
With  increasing  temperature,  the  value  increases.  It  was 
found  in  the  mean,  that  for 

about  20. 10°   C=o.oo6io 
20.25°   C=  0.00637. 

Effect  of  Added  Substances  on  the  Velocity  of  Transformation 
The  decrease  in  the  rotation  of  aqueous  dextrose  solutions 
with  the  time,  is  sometimes  hastened  and  sometimes  retarded 
by  the  presence  of  other  substances,  such  as  acids,  alkalies 
or  salts,  and  the  behavior  of  these  bodies  appears  to  be  a  cata- 
lytic one.  Numerous  investigations  by  Levy  an.d  Trey  have 
shown  the  following  facts : 

a.  Bodies  Which  Hasten  the  Change 

i .  Acids. — The  effect  of  these  wras  first  noticed  by  Krdmann1 
in  the  case  of  milk-sugar.  According  to  Levy,2  the  velocity 
constant,  C,  (formula  II)  assumes  the  following  values  when 
dilute  acids  containing  ^  mol.  to  the  liter  were  employed  as 
solvents  : 


C 

Temperature. 

Relative 
acceleration. 

Water 

Water     

o  006^7 

2O  2^ 

Hydrochloric  acid  

0.02300 
o  0228^ 

•^••'0 
20.25 

100 

Trichloracetic  acid  .  .  • 

0.02325 
o  01886 

20.25 

90.99 
96.67 

Dichloracetic  acid  
Monochloracetic  acid. 

0.01670 
0.01004 
o  00716 

20.2 
20.25 
2O  2 

7I-95 
62.41 
17.25 

Propionic  acid  «... 

o  006^6 

TO  8 

4-/u 
i  f>-i 

19.0 

1.03 

It  appears,    therefore,    that  in   their  accelerating  behavior, 
the  acids  stand   in  the  order  of  their  affinity  coefficients,   as 

1   Krdmann  :  Jaliresber.,  1X55,  j>.  671. 
1  Levy  :  IJQC.  ri/.,  p.  301. 


RATE    OF    CHANGE    OF    ROTATION  269 

measured  by  electrical  conductivity,  the  catalysis  of  methyl 
acetate  or  by  their  power  of  inverting  cane-sugar. 

Trey1  came  to  the  same  conclusion  in  experiments  on  the 
action  of  hydrochloric,  sulphuric,  oxalic,  and  cacodylic  acids. 
But,  on  the  other  hand,  he  found  a  retarding  effect  with  acetic 
and  propionic  acids. 

The  value  of  the  constant,  C,  increases  as  a  matter  of 
course,  with  the  strength  of  the  acid.  For  example,  with  T\ 
normal  hydrochloric  acid,  the  value  is  C  =  0.00971. 

2.  Bases. — These  bring  about  an  enormous  acceleration  in 
the  velocity  of  transformation  of  all  sugars,  so  that  in  a  very 
few  minutes,  or  immediately  after  the  addition  of  the  base,  the 
normal  end  rotation  is  reached.  This  was  first  noticed  by 
Urecrr  in  the  case  of  milk-sugar  and  ammonia,  and  he  found 
also  that  in  time,  the  rotation  sinks  still  lower,  which  may  be 
accounted  for  by  a  chemical  change  in  the  sugar." 

The  action  of  ammonia  on  different  sugars  has  been 
thoroughly  investigated  by  Schulze  and  Tollens.4  They  found 
that  by  application  of  o.i  per  cent,  ammonia,  after  5  to  10 
minutes,  even,  the  normal  lower  rotation  is  reached  with 
dextrose,  xylose,  arabinose,  galactose,  rhamnose,  levulose,  and 
ordinary  milk-sugar.  This  was  found  to  be  the  case  with 
^-milk-sugar  and  maltose  also,  from  which  it  is  seen  that  not 
only  the  higher,  but  the  lower  rotation  as  well,  is  destroyed 
immediately.  Schulze  and  Tollens  observed,  for  example, 
the  following  changes: 

Xylose:                           [«]  D  Maltose  hydrate:                      \_a~\  D 

In  water  constant -f-  18.7°  In  water  constant -\-  130° 

In  ammo-   f  After  10  min.  —  14.8  In   ammo-    f  After  loniin.      -  126.1 

niaof  20.4^  After    i  day     -f  u.o  niaof2O.4J  After  7^  hours  -j-  I23-9 

per  cent,     j  After    3  days  -f    5.7  per  cent.    [After  i    day            118.1 
d  —  0.924    [After    5  days   —    5.9 

In  the  same  manner  Trey5  found  in  a  solution,  which  contained 
in  100  cc.,  2.25  grams  of  dextrose  anhydride  and  0.085  NH3, 

1  Trey  :  Ztschr.  phys.  Chem.,  18,  205  ;  22,  448. 
-  Urech:  Her.  d.  chem.  Ges.,  15,  2132  (1882). 
Trech  :  Ibid.,  17,  1545. 

4  Schulze  and  Tollens:  Ann.  Chem.  (L,iebig),  271,  49. 

5  Trey:  Ztschr.  phys.  Chem.,  22,  439. 


2JO  SPECIFIC    ROTATION 

After  15  inin.       [^J />  ~    "^    52-2  (normal) 
After  24  hours  -{-  49.6 

After  65  days  -f-  44.9 

The  alkali  hydroxides  have  an  equally  strong  action  ;  by 
means  of  ^^  normal  potassium  hydroxide  solution  the  final 
rotation  in  dextrose  is  reached  almost  instantly.  With  greater 
concentration,  a  further  progressive  decrease  is  observed  which 
may  even  pass  into  left  rotation.  Thus,  Trey1  found  in  a 
solution  containing  in  100  cc.  2.25  grams  of  dextrose,  and  0.2 
gram  of  sodium  hydroxide,  the  following  specific  rotations  : 

After  15  minutes  [«]/>  =  +  52.7  (normal) 
"     24  hours       [a]/,  ==  -f-  36.7 
"     48     "  [a]/,  =  -f  26.0 

"     34  days         [a]/,  =  +  15.1 
"     65     "  [a]/>  =      -    0.4 

It  is  evident  that  some  chemical  change  takes  place  here. 
As  Lobry  de  Bruyn  and  Alberda  van  Ekensteiir  have  observed, 
the  reciprocal  conversion  of  dextrose,  levulose,  and  mannose 
into  each  other  by  the  catalytic  action  of  small  amounts  of 
alkali  is  possible. 

It  is  only  with  very  weak  bases  that  the  fall  in  the  multi- 
rotation  may  be  quantitatively  followed.  This  was  done  in  a 
dextrose  solution  containing  urea  with  which  Levy1'  found  the 
following  values  for  the  velocity  constant,  C  (formula  II)  : 

(  10  per  cent.  :  C      0.008^  at  about  20.2° 
Urea  in  solution  < 

I    5  per  cent.  :   C  -  0.00749  at  about  20.0° 

These  numbers  are  but  little  larger  than  given  above  for  pure 
water. 

j.  Salts. — These  all,  with  the  exception  of  sodium  chloride, 
have  an  accelerating  action  on  the  fall  of  rotation  in  dextrose. 

Salts  with  an  alkaline  reaction  bring  about  the  normal  end 
rotation  within  a  few  minutes.  This  is  the  case  with  sodium 
carbonate,  with  which,  after  long  standing,  no  further  decrease 
is  observed  ;  this  salt  is  therefore  suitable  for  quickly  destroy- 
ing the  multirotation.  Potassium  cyanide  sometimes  produces 
a  marked  decrease  below  the  normal  end  value  (Trey).4 

1  Trey  :  Loc.  cit.t  p.  438. 

'-'  Lobry  de  Bruyn  and  All>erda  van  Eckenstein  :    Her.    d.  chein.   (ies.,   28,  III,  ,^078; 
Kec.  trav.  chim.  Pays-Bas.,  14,  156,  203. 
*  J*evy  :  Ztschr.  phys.  Chem.,  17,  324. 
4  Trey  :  Ibid.,  aa,  440. 


RATE    OF    CHANGE   OF    ROTATION  2JI 

Salts  with  a  neutral  reaction  cause  a  slower  decrease  in  the 
multirotation,  so  that  the  conversion  may  be  followed  and  meas- 
ured. Levy1  found  the  velocity  constant  C  (formula  II),  for 
dextrose  in  the  presence  of  the  following  salts  : 

C.  Temp, 

Pure  water 0.00610  20.  i  ° 

Sodium  sulphate,  anhydrous,  10 per  cent. ..  0.00844  20.0 

Sodium  sulphate,  anhydrous,  5  per  cent- . .  0.00800  20.2 

Sodium  acetate,  10  per  cent 0.03897  20.  i 

According  to  Levy,  the  action  of  these  salts  depend  on  this, 
that  through  partial  hydrolysis,  sodium  hydroxide  is  formed 
which  brings  about  the  acceleration.  This  hydrolysis  takes 
place  to  a  greater  extent  with  sodium  acetate,  than  with  the 
sulphate,  and  this  explains  its  much  stronger  effect. 

Trey  has  demonstrated  the  accelerating  action  of  the  follow- 
ing salts  on  the  fall  of  rotation  in  dextrose  :'-' 

Sodium  bicarbonate,  Magnesium  chloride, 

Potassium  nitrate  Magnesium  sulphate, 

Potassium  iodide,  Aluminum  chloride, 

Ammonium  chloride,  Cadmium  iodide, 

Ammonium  thiocyanate,  Lead  acetate, 

Barium  chloride,  Mercuric  chloride. 

Trey  found  also  that  sodium  sulphate  lessens  the  effect  of 
sulphuric  acid. 

b.   Bodies  Which  Retard  the  Change 

/.  Sodium  Chloride. — The  behavior  of  this  salt,  different 
from  that  of  all  others,  was  first  noticed  by  Levy3  who  found 
the  following  values  for  the  constant  C  (by  formula  II), 
which  are  smaller  than  that  for  water  : 

Dextrose  solution .                                                          C.  Temp. 

In  pure  water 0.00610  20.1° 

In  10  per  cent,  sodium  chloride 0.00533  20.0 

In    5  per  cent,  sodium  chloride 0.00586  20.2 

Trey4  confirmed  this  retarding  action  of  common  salt  by 
the  following  series  of  observations,  in  which  the  changes  in 
the  specific  rotation  of  dextrose  wTith  the  time  of  standing  were 
found  : 

1  L,evy  :  Loc.  cit. 

-  Trey  :  Ztschr.  phys.  Chem.,  22,  429. 

:  I^evy  :  Ibid.,  17,  320. 

4  Trey  :  Ibid.,  22,  429,  436. 


272 


SPECIFIC    ROTATION 


In      (Dextrose 

2.250 

9.000 

cc-      (xad 

c 

0.2925 

0 

0.2925 

0-585 

1.170 

Time,    5111111. 

102.7° 

100.0° 

Time,  ismin. 

95-6 

96.0° 

94.2 

96.8° 

97-3° 

97-1° 

Time,  25inin. 

87.3 

90.0 

86.4           89.6 

89.9 

89.7 

Time,  35inin. 

82.2 

84.4 

80.2 

83-2 

83.7 

83.3 

Time,45min. 

78.2 

80.4 

74-6 

77-9 

78.5 

78.1 

Time,  55inin. 

74-4 

76.7 

69.9            73.1 

73-2 

73-6 

Time,  65min. 

72.2 

749 

66.2           69.4 

69.6 

70.7 

Time,  -s: 

50.7° 

5i.i° 

50.8°          51.1° 

51-7° 

S2  2° 

In  presence  of  common  salt  the  decrease  in  the  rotation 
follows  more  slowly  than  in  pure  water.  It  is  seen  also  that  a 
variation  in  the  amount  of  salt  is  of  little  importance.  An 
explanation  of  this  peculiar  behavior  of"  the  salt  is  wholly 
lacking. 

2.  Alcohoh  and  Other  Organic  Substances. — Levy  obtained, 
according  to  formula  II,  lower  values  for  the  constant,  C, 
with  solutions  of  dextrose  in  aqueous  ethyl  alcohol  than  in 
pure  water. 


Pure  water 0.00610 

1  ,,,  mol.  alcohol 0.00555 

In  i  liter -'  ' :,  mol.  alcohol 0.00521 

i  mol.  alcohol 0.00510 


Temp. 
20.1° 

2O.O 
20.0 
2O.  I 


In  aqueous  methyl  alcohol,  the  retarding  action  of  which 
had  been  already  observed  by  Dubrunfaut,1  Trey2  found  that 
the  decrease  in  the  rotation  takes  place  somewhat  more  rapidly 
than  in  ethyl  alcohol. 

Solutions  of  dextrose  in  pure  methyl  alcohol  show  like- 
wise, multirotation,  and  the  decrease-  in  the  same  may  be 
retarded  by  addition  of  other  organic  substances.  Trey:i  found 
the  velocity  constant  from  formula  I  for  the  following 
solutions  : 

1  Dubrunfaut:  Compt.  rend.,  42,  228  (i 
'-'  Trey:  7,tschr.  phys.  Chein.,  17,  200. 
*  Trey  :  Ibid,,   17, 


CAUSE    OF   THE    MULTIROTATIOX    OF    SUGARS  273 

In  100  cc.  of  the  methyl  alcohol  solution.  C. 

i-°775  gram  dextrose 4.95 

i. 02 10     "  "  0.1525  gram  phenol 2.54 

0.9615     "  -0.1543    "     naphthalene 1.77 

0.8504     "  --0.2725     "     diphenylamine i.ii 

°-$495     "  "  0-3072    "     succinamide 0.85 

Finally,  a  retardation  in  the  decrease  in  rotation  in  aqueous 
dextrose  solutions  has  been  noticed  on  addition  of  acetone  and 
also  of  cane-sugar  (Trey).1 

74.  Cause  of  Multirotation  of  the  Sugars. — On  this  point,  the 
following  views  have  been  advanced  : 

1.  The  change  in  the  rotation   may  depend  on  this,  that  in 
the  original  freshly  prepared  solution,  molecular  aggregations 
'crystal  molecules)  of  active  form  may  exist,  which  gradually 
break    down    into    molecules    of    lower     rotation    (Landolt," 
Pribram, :1  Hammerschmidt,4  WyroubofT) /' 

By  cryoscopic  methods,  as  already  explained  in  §  63,  these 
aggregations  cannot  be  shown,  because  they  no  longer  exist 
in  dilute  solutions. 

2.  With  dextrose,    which  shows  multirotation   as  an  anhy- 
dride as  well  as  hydrate,  the  fall  in  rotation  may  be  due  to  the 
taking  up,  or  splitting  off,    of  water.     This  view  which  was 
brought  forward  years  ago  by   Erdmann(i  and  Bechamp,7  and 
later  abandoned  by  its  authors  has  recently  come  to  light  again. 
K.  Fischer  is  of  the  opinion  that   anhydrous  grape-sugar  dis- 
solves first  as  Q.Hj.,0^  (with  high   rotation)    and  is  gradually 
transformed  into  the  hydrate  or  heptahydric  alcohol,  C,.H14O7 

with  lower  rotation).  According  to  Jacobi,"  this  view  is 
confirmed  by  the  fact,  that  in  birotating  glucose  anhydride 
solutions,  the  formation  of  the  phenyl  hydrazone  takes  place 
more  rapidly  than  in  the  lower  rotating  solutions.  On  the 

Trey  :  Ztschr.  phys.  Chem.,  22,  450,  456. 

I^andolt  :  "  Optisches  Drehungsvermogen,"  ist  ed.     : 

Pribram  :  Wien.  Monatsheft,  9,  401. 

Hammerschmidt  :  Ztschr.  f.  Riibenzucker-Ind.,  40,  939. 

Wyrouboff  :  Compt.  rend.,  115,  832. 

Krdmann  :  Jahresbericht,  (1855),  p.  672. 

Bechamp:  Ibid.,  (1856),  p.  639,  640;  Compt.  rend.,  42,  640,  896. 

E.  Fischer  :  Ber.  d.  chem.  Ges  ,  23,  2626. 

Jacobi  :  Ann.  Chem.  (L,iebig),  272,   179. 

18 


274  SPECIFIC    ROTATION 

other  hand,  Tollens1  assumed  that  the  anhydride  on  dissolving 
is  transformed  immediately  into  the  hydrate  (with  high 
rotation),  as  evolution  of  heat  follows,  and  that  then  gradually, 
in  solution,  a  reformation  of  the  anhydride  (with  low  rotation) 
takes  place.  Such  a  reaction  is,  however,  thermodynamically 
impossible.  With  dextrose  hydrate,  which  dissolves  without 
liberation  of  heat,  the  high  rotation  of  the  unchanged  com- 
pound which  at  first  appears,  and  the  decrease  in  the  rotation, 
would  both  have  to  be  ascribed  to  the  gradual  formation  of 
anhydride. 

Arrhenius,1  and  also  Brown  and  Morris, :<  have  found  that 
birotating  and  normally  rotating  dextrose  solutions  are  cryo- 
scopically  identical.  But  this  observation  does  not  decide  the 
question  as  to  the  presence  of  hydrate  or  anhydride  in  solution, 
because  the  difference  between  the  freezing-point  depressions 
of  the  two  would  be  so  small  as  to  fall  within  the  limits  of 
errors  of  experiment. 

3.  The  differences  in  rotation  of  multirotating  sugars  may 
be  due  to  the  existence  of  different  isomeric  modifications, 
which,  in  solution,  are  gradually  transformed  into  each  other. 

Such  an  assumption  was  made  as  early  as  1856  by  Erdmann,1 
Dubrunfaut,5  and  also  by  Bechamp,"  and  with  the  under- 
standing that  of  the  different  modifications,  one  is  crystalline 
and  the  others  amorphous.  But  since  then,  as  explained  in 
§§71  and  72,  Tanret  has  succeeded  in  obtaining  tthe  wo  or 
three  different  rotating  forms  of  several  sugars  in  crystalline 
condition,  and  in  showing  the  equality  in  their  molecular 
weights,  and  also  their  reciprocal  convertibility.  There 
remains,  therefore,  only  the  question  as  to  the  constitution  of 
these  isomers,  and  on  this  point  van't  Hoff7  called  attention 
( 1894)  to  the  clue  which  may  be  found  in  the  analogy  existing 
between  the  sugars  and  the  rotating  lactone- forming  acids,  as 
gluconic  acid,  arabonic  acid,  saccharic  acid,  and  others.  With 

Tollens :  Her.  d.  chem.  Ges.,  26,  1799. 
Arrhenius  :  Ztschr.  phys.  Chem.,  a,  500  (1888). 
Brown  and  Morris:  Chem.  News,  57,  196  (1888). 

Erdmann  :  Jahresbericht,   (1855),  672;  (1856),  639;   Her.  d.    chem.  Ges.,   13,2180 
(1880). 

Dubrunfaut  :  Compt.  rend.,  43,  739  (1856). 

Bichamp  :  Compt.  rend.,  43,  896  (1856)  ;   Bull.  Soc.  Chitn.,  (3),  9,  511    (1893). 

van't  Hoff:  "  I, age  rung  der  Atonic  im  Raume,"  2d  ed.,  p.  in. 


CAUSE    OF   THE    MULTIROTATIOX   OF   SUGARS  275 

these  latter,  as  will  be  explained  in  §  75,  the  increase  in  rota- 
tion, which  follows  on  solution  in  water,  depends  on  the 
formation  of  their  lactones,  which  possess  a  cyclic  constitution. 
On  the  other  hand,  a  decrease  in  rotation  results  when  the 
lactones  are  changed  into  the  acids,  with  destruction  of  the 
ring  formation.  According  to  this,  for  example,  of  the  two 
modifications  of  xylose  the  higher  rotating  might  have  the 
formula 

CH.X)H— CH—  (CH.OH)2— CH.OH, 

1 O I 

and  the  change  into  the  lower  rotating  form  might  depend  on 
the  conversion  into  a  body  of  this  structure, 
CH2OH— (CH.OH),— CHO. 

Further,  it  was  observed  simultaneously  by  E.  von  Lipp- 
mann1  and  by  Lobry  de  Bruyn  and  Alberda  van  Ekenstehr 
that  in  regard  to  the  three  differently  rotating  ^/-glucoses,  the 
assumption  of  the  ethylene  oxide  constitution  of  the  same  pro- 
vides for  two  stereoisomeric  forms,  and  that  the  third  or 
aldehyde  structure  may  also  appear. 

While  it  is  true  that  the  proof  of  which  constitution  must 
be  ascribed  to  each  of  the  three  forms  of  glucose,  etc. ,  is  as 
yet  a  very  difficult  question,  we  may  now  consider  this  much 
as  established,  that  the  cause  of  the  multirotation  in  the  sugars 
is  to  be  found  in  the  transformations  of  their  different  isomeric 
modifications.3 

II.   Multirotation  of  Ovy- Acids  and  Their  Lactones. 

75-  In  1873  Wislicenus*  made  the  observation  that  the 
rotating  power  of  ^-lactic  acid,  in  aqueous  solution,  is  gradu- 
ally changed  at  the  ordinary  temperature,  and  he  found  the 
cause  of  this  to  lie  in  the  slow  hydration  of  anhydrous  mole- 
cules which  were  contained  in  the  solution.  The  same  behavior 
was  later  noticed,  especially  by  Tollens,  in  other  oxy-acids,  as 
saccharic  acid,  gluconic  acid,  rhamnonic  acid  and  others,  and 

1  E.  v.  I^ippmann:  Ber.  d.  chem.  Ges.,  29,  203;  "  Chemie  der  Zuckerarten,"  (1895) 
p.  130,  990,  992. 

'-'  lyobry  de  Bruyn  and  Alberda  van  Ekenstein:  Ber.  d.  chem.  Ges.,  28,  3081  (1895) 

3  See  a  recent  paper  by  Brown  and   Pickering  (J.  Chem.  Soc.,  71,  769)  on  this 
subject. 

4  Wislicenus:  Ann.  Chem.  (I^iebig),  167,  302. 


276  SPECIFIC   ROTATION 

also  in  their  lactones.  The  latter  have  always  a  markedly 
greater  rotation  than  the  corresponding  acids,  and  if  the 
lactones  are  dissolved  in  water  there  is  found  a  progressive 
decrease  in  the  rotation  until  a  constant  value  is  finally 
reached.  If,  on  the  other  hand,  fresh  solutions  of  the 
acids  are  made  by  using  salts  of  the  same  and  hydrochloric 
acid  in  addition,  then  a  gradual  fall  of  the  rotation  may  be 
observed,  and  finally  the  same  value  is  reached  as  is  obtained 
by  starting  with  the  lactone. 

The  cause  of  the  phenomenon  is  found  in  this  fact,  that  in 
aqueous  solution,  both  the  acid  and  its  lactone  suffer  a  recipro- 
cal decomposition  which  goes  on  very  slowly  and  continues 
until  a  condition  of  equilibrium  is  reached  when  the  liquid  con- 
tains both  substances  in  definite  proportions.  This  ratio 
varies  with  the  temperature,  and  in  such  a  manner  that  with 
elevation  of  temperature  there  is  an  increase  of  the  lactone 
molecules,  and  therefore  of  the  rotation.  On  cooling,  the 
rotation  decreases  to  its  former  value. 

The  velocity  relations  in  the  conversion  of  the  oxy-salts  into 
their  lactones,  and  the  reverse,  have  been  studied  especially  by 
P.  Henry1  who  made  use  of 

•y-oxybutyric  acid  and  lactone. 

CH.,OH—  (  CH,  ),—  COOH         CH,—  (CH.,),-CO 

o 

y-oxyvaleric  acid  and  lactone. 

CH3—  CH.OH—  (  CH,  i  —  COOH        CH,-CH—  (CH.),—  CO 

O  -       ' 
in  which  case  by  titrations  the  following  relations  were  found  : 

a.  The  transformation  of  the  oxy-acids  into  lactones  is 
hastened  by  addition  of  acids,  which  act  catalytically.  The 
velocity  is  expressed  by  the  equation  corresponding  to  a 
reaction  of  the  first  order, 


in  which  A  represents  the  original  amount  of  oxy-acid,  x  the 
amount  of  lactone  formed  in  the  time,  /,  and  C  the  constant 
of  the  reaction.  It  was  found  that  different  acids  added  act 

'P.Henry:/!  Cliem.,     10,   96    (1892).     St-i-    ftlio:     K.    Hj.lt:   i:<  r     d. 

chem.  Ges.,  34,  1236  (1891)  ;  Unno  Collar  by*  <  IK-HI  .  10,  130  (1*92). 


THE  MULTIROTATIOX  OF  OXY-ACIDS  AND  LACTONES      277 

with  an  intensity  proportional  to  their  affinity  coefficients. 
7-Oxybutyric  acid  is  transformed  only  partially,  but  with 
7-oxyvaleric  acid  the  reaction  is  complete. 

b.  In  the  case  of   spontaneous  transformation  of  the  oxy- 
acids  into  lactones,  the  relations  observed  correspond  to  the 
assumption  that  the  oxy-acid  still  remaining,    at  any  moment, 
can  accelerate  its  own  conversion  ;  that  is,  autocatalysis  comes 
into  play.     The  above  formula  no  longer  holds  good,  since  in 
this  case  the  velocity  of  the  reaction  is   proportional  to  the 
amount  of  acid  not  dissociated,    that  is  to   C(A  —  x},  con- 
sidered as  an  indifferent  body,  and  also  to  the  dissociated,  cata- 
lytically    acting    acid,     which    at    any    moment  is    equal    to 
y{A  —  x),  where  y  is  a  certain   function   which  expresses  the 
number  of  H-ions.     The  complete  expression   for  the  velocity 
is  given  then  by  the  equation  obtaining  for  a  reaction  of  the 
second  order, 

d.\ 

—  =  Cy  (A  -  *)', 

which  was  found  to  give  values  for  C  in  accord  with  the 
results  of  experiment.  For  the  derivation  of  y  the  original 
paper  must  be  consulted.1 

c.  Addition  of  bases  to  the  solution  of  the  lactone  hastens 
the  conversion  of  the  latter  into  acid.     When  the  two  bodies 
are  mixed  in  equivalent  proportions  the  velocity  of  the  reaction 
corresponds  to  the  equation, 


It  was  found  that  the  activity  of  the  bases  is  proportional  to 
the  intensity  of  their  basic  character. 

Observations.  —  On  the  multirotation  of  oxy-  acids  and 
lactones  the  most  important  results  are,  in  the  main,  the  follow- 
ing, and  among  these,  those  concerning  saccharic  acid  are 
given  first,  because  here  the  condition  of  equilibrium  referred 
to  above  is  most  clearly  discerned  (c  =  concentration  in  100 
cc.).2 

1   See  alsoH.  Jahn  :  "  Grnndriss  der  Electrochemie,"  (1895),  p.  118. 

-  In  the  calculation  of  the  specific  rotation  of  the  several  solutions,  which  contain 
acid  and  lactone  at  the  same  time,  it  is  necessary  to  express  the  concentration  in  terms 
of  either  one  or  the  other.  In  each  case  it  is  stated  to  which  txxlies  the  numbers 
given  refer. 


278 


SPECIFIC    ROTATION 


d- Saccharic  acid ',* 


Acid  ammonium  salt  with  HC1. 
c  =  4.634  acid  =  4.237  lactone. 


Saccharic  acid  lactone, 
C.H8Or 


Weighed  directly. 
c  =  10.213  lactone. 


After    j  day  

T     V-A 

no 

JJCglillllllg      . 

•  •       2  days  « 

"      6     4' 

16  d 

44     n     " 

<i       ^     •  < 

"       T7       " 

"       8     " 

18  «: 

"      91        " 

"        12       "'     ' 

20  ^ 

24                 

"        1A       " 

•*^o 

2n  S 

"       7T         " 

1  *       2Q       '  ' 

22  7 

31            

"     in     " 

Calculated 

"       10       " 

for  C..H.O. 

<(     «;6     " 

W» 

•>•»  «o 


32.3 
30.5 
26.3 

24.9 
24.1 
23.2 

23.1 

22.9 
22.9 
22.8 
22.5 
Calculated  for  CHHKO7. 

With  norisosaccharic  acid,  C6H10O,,,  and  isosaccharic  acid, 
CSH8O7,  almost  the  same  rotation  is  likewise  found  after  warm- 
ing the  solutions  (-(-  49  to  -f-  52 ).2 


2. 


After 


Rhamnonic  acid, 

c.H.,0.. 

Strontium  salt  and  HC1. 
c.  —  6.204  acid. 


10 
18 

33 

2 

3 
5 


minutes --    7.7C 

44       n. i 

"      15-8 

hours     27.9 


days 


29.4 
29.2 


Rhamnonic  acid  lactone 

Weighed  directly. 
c  =  5.680  lactone  =  5.960  acid. 

At  once -  34.3° 

After  i  day 34.3 

"     2  days 33.7 

3  33-7 

\  hour  heated ....        34.8 

3  days 34.0 

Calculated 
for  C,.H,.,O«. 


Heated    \    hour    at  •> 

100°  and  cooled      /  ' 
After  i  day 30.7 

44     3  days 30.1 

"     5     " 30.1 

Calculated  for  CBH12O«. 

It  appears,  therefore,  that  in  the  condition  of  equilibrium 
the  liquid  contains  mainly  the  lactone,  and  that  probably  the 
latter  is  not  transformed  into  the  acid  at  all.:! 

1  Sohst  and  Tollens  :  Ann.  Chem.  (I,iebig),  345,  10,  12. 
1  Tiemann  :  Ber.  d.  chem.  C.es.,  37,  137. 

hnelle  and  Tollens  :  Ann   Chem.  (Ijebivj),  371,  72. 


THE  MULTIROTATIOX  OF  OXV-ACIDS  AND  LACTOXES      279 


3 .  d-  Glucon  ic  a cid, ' 

C.H..O,. 

Calcium  salt  with  oxalic  acid. 

Mi 

At  the  beginning —  1-74° 

After  14  to  21  days. ...    —  10  to  12 

Heated  to  100° 23.4 

After  cooling 10  to  12 

Calculated  for 


Gluconic  acid  lactone, 


C.H..O.. 

c  =  7.5  lactone. 

[«L> 

After  10  minutes —  55.9° 

"      i  day —  47.6 

"      3  days -   44.0 

"     8  days —  .36.0 

"    ii  days —  33.6 

C,;H,.,O7.  "   47  days -7-18.9 

Calculated  for  C6H12O7. 

The  conversion  of  the  lactone  into  the  acid  takes  place,  there- 
fore, very  slowly  and  after  forty- seven  days  is  not  yet  complete. 
It  may  be  further  remarked,  as  with  rhamnonic  acid,  that 
heating  the  acid  leads  to  increased  formation  of  lactone. 


4.  d-Galactonic  add,' 

C.H.A. 

Calcium  salt  with  HC1. 
c  =  7.5?  acid. 

[«]/. 

After  10  to  15  min. —  10.6° 

5  hours —  13.8 

6  days —  39.2 

"     15  ^ays —  45.9 

Heated  to  100° —  59.7 

After  14  days —  53.0 

Calculated  for  C6H,,O7. 


Galactonic  acid  lactone, 
CBH,006. 

Weighed  as  hvdrate. 
C-.H^Oe  +  H2O.  '  c  =  6.85. 

M, 

After  10  min. —  64.2° 

"        24  hours — 63.7 

"      warming — 63.9 

2.  c  =  7.0 

After  10  min —  6.5.5 

"       3  days —64.3 

Calculated  for  QH12O7. 


With  many  bodies,  the  following  for  example,  the  observa- 
tions are  still  incomplete. 


5 .  A  ra  bon  ic  acid, ' 

C-.H.A, 

Strontium  salt  and  HC1. 
c  =  ^.46  acid. 

M* 

After  10  min —  8.50° 

' '       4  hours —  30.0 

' '        6  hours —  37.0 

"      20  hours — 45.0 

' '       2  days —  45.9 

"       2  months 48.2 

Calculated  for 


Arabonic  acid  lactone  * 

C.HA- 

Weighed  directly. 
c  =  9.749  lactone. 


Beginning. .  . . 
After  14  hours 


-65.9° 

-65.9 

Calculated  for 
C5H1006. 

(—  73-9 
calculated  for 


i  Schnelle  and  Tollens:  Ann.Chem.  (i.iebig),  271,  74. 

'-'  Schnelle  and  Tollens:  Ibid.,  271,  M. 

-  Allen  and  Tollens:  Ibid.,  260,  312. 

4  Hi<cher  and  Piloty:  Ber.  d.chem.  Ges.,  24,  4219. 


280  SPECIFIC    ROTATION 

6.  Xvlonic  acid,1  Xvlonic  acid  lactone 

C5H100«.  C.H.O,. 

Observations  on  the  acid  only  have  been  made. 

Strontium  salt  and  HC1.    c  =  3.428  C5Hi0O6. 

After         10  min.         4  hours        6  hours        20  hours       later       2  months 
[«]7)  -7-1  o  +7-1  -f  17-2  17-5        20.9°. 

7.  •       Saccharinic  at  id,  Saccharin, 

C.H.A.  C.H,.o5. 

For  saccharin  (c=  10.4)  there  was  found  : 

After  S  min.  3  days  4  days          7  days  u  days 

[a],,  94-2  90-7  90-5          -T  88.9  -1-88.7°. 

The  changes  in  the  rotation  of  saccharinic  acid  (salts  of  the 
acid  with  HC1)  have  not  yet  been  investigated. 

Isosaccharin  (c  ==  10,  [**]„-:  -f  63°)  and  metasaccharin 
(c  =  -  10,  [<*]/,  =  -  46.7°)  show  constant  rotation.' 

8 .  ft-  Glucohepton  ic  acid  1  acton  c , n  C7  H ,  ,O. . 

c        10.422  after  20  min.  24  hours 

[a]/)    =  -  79-2  67.7°. 

9.  Anhydrides  of  d-Lactic  Acid,  C.,H,.O3. 

As  Wislicenus  has  shown,  the  right-rotating  acid  leaves  on 
concentration,  products  which  contain  certain  amounts  of  the 
strongly  left-rotating  anhydride,  CfiHlftO-,  and  probably  the 
lactide,  C6H,,O4.  These  last,  when  brought  into  aqueous  solu- 
tion, pass  gradually  back  into  lactic  acid,  which  may  be 
recognized  by  the  fact  that  after  neutralization  the  liquid 
becomes  slowly  acid.  In  consequence  of  this,  the  rotation 
increases,  but  at  the  ordinary  temperature,  this  increase  is 
appreciable  only  after  some  months. 

If,  after  standing  some  time,  the  solution  be  diluted  with 
water,  this  produces  at  first  a  decrease  in  the  rotation,  and  then 
later  a  gradual  increase.  According  to  Wislicenus,  the 
decrease  depends  on  the  formation  of  a  hydrate,  C.,Hr>O.t .  II  <  ). 
whose  rotation  must  be  smaller  than  that  of  the  acid. 

Among  the  experiments  which  \Vislicenus1  has  made,  tin- 
following  may  be  cited  : 

1  Allen  and  Tolh  MS  :  Ann.  Cht-in.  (I,if1>itf),  260,  JII. 

.m-llr  and  T«>llfii>  ;   //.„/.,  371,  66. 
I  ischer  :  Ibid.,  770, 
4  U'i  '"/.,  167,  324  (1873)  ;  also  164,  iM 


THE  MULTIROTATION  OF  OXY-ACIDS  AND  LACTONES.     28 1 

C8H60, 

in  100  cc.  \_(x\V 

Beginning 42.65  0.41° 

After  7  months 42.97  +  2.85 

"     9         "       42.97  2.91 

"     dilution 15-74  M3 

"  44  days 15.74  +1.84 

Among  bodies  of  Class  II  it  is  found,  without  exception,  that 
the  lactones  possess  a  much  stronger  rotating  power  than  their 
corresponding  acids.  In  the  constitution  of  the  two  groups, 
there  is  a  marked  difference,  as  we  have  for  example  : 

Saccharic  acid.  .Saccharic  acid  lactone. 

CO  .OH  CO  .  OH 

I  I 

CH  .OH  CH  .  OH 

CH  .  OH  ,CH 

CH  .  OH          /  CH  .  OH 


CH  .  OH          \   CH  .  OH 
I  \  I 

CO  .  OH  \CO 

The  higher  rotation  of  the  lactone  may  be  attributed  to 
the  ring  structure  contained  in  it.  See  §  84. 

Furthermore,  it  has  not  been  shown  in  all  cases  that  the 
decrease  in  rotation,  which  is  observed  with  the  lactones, 
depends  on  hydration.  In  the  case  of  the  ytf-glucohep tonic 
acid  lactone,  referred  to  above,  Fischer  was  unable  to  discover 
any  gradual  formation  of  acid.  Besides,  the  change  in  rotation 
may  take  place  in  solutions  which  are  not  aqueous.  This  was 
first  observed  by  Colson1  with  the  anhydride  of  diacetyl  tar- 
taric  acid,  which  showed  at  first,  in  acetone,  a  rotation  of 
12°,  and  after  half  an  hour  only  —  10.18°. 

///.    Multirotation  of  a  Few   Other  Substances. 

76-  Here  we  have  the  following  bodies: 

Formylfenchylaminc,  C]0H1T.XH.HCO. — A  solution  in  chloro- 
form showed  a  decrease  in  rotation  which  ceased  after  12 
hours.' 

i  Colson  :  Bull.  Soc.  Chim.,  (3)  7, 
-  Binz:  Ztschr.  phys.  Chem.,  12,  726. 


282  SPECIFIC    ROTATION 

/OH  (i) 

p-  Oxy-benzylidcnefcnchvlaminc,   CKH4^ 

\CH  =.  N.C10H1T  (4) 

With  a  solution   in  chloroform    (p  =  1.28,  d  --  1.4905)  there 
was  found:1 

For  the  fresh  solution [a]  *;  77° 

After  18  hours [a-]  £  =  -f   72. 

Nicotine,  dissolved  in  water. — Pribram  observed  that  a  solu- 
tion of  20.169  per  cent,  strength,  with  a  density  of  1.0149, 
when  allowed  to  remain  in  the  polarization  tube  at  the  ordin- 
ary temperature,  exhibited  the  following  increase  in  rotation: 

[«]5?  [«]« 

for  /  =  3.999  dm 

Fresh  solution —7.188°  87.81° 

After  12  hours  7.623  93-13 

After  1 8  hours 7.903  96.55 

After  48  hours 7.904  96.56 

According  to  Pribram,  this  phenomenon  depends  on  the 
formation  of  a  hydrate,  since  nicotine  and  water  mix  with 
marked  evolution  of  heat.  In  freshly  prepared  20  per  cent. 
solutions,  the  conversion  does  not  seem  to  be  completed  at 
once,  but  to  require  a  certain  time.  From  the  increase  in  the 
rotation  it  must  be  concluded  that  the  hydrate  is  more  active 
than  the  pure  base.2 

G.  Relations  Between  the  Amount   of  Rotation  and  Chemical   Con- 
stitution 

77.  Preliminary  Remarks. — A  large  number  of  investigations 
have  been  carried  out  with  these  relations  in  view,  but  up  to 
the  present  time  without  yielding  very  satisfactory  results. 
In  establishing  the  rotating  power  of  groups  of  bodies  of  given 
chemical  constitution,  certain  regularities  could  be  recognized, 
but  almost  always  these  were  clouded  by  exceptions  more  or 
less  numerous.  The  cause  of  this  may  rest  in  the  uncertainty 
which  is  connected  with  the  determination  of  the  specific 
rotation  of  many  substances.  With  solid  bodies  which  can  be 
investigated  only  in  solutions,  the  rotation,  as  is  well  known, 

1  Binz:  IJH-.  fit. 

2  Pribram  :  Ber.  d.chem.  (its.,  20,  1847. 


ROTATION    AND    CHEMICAL    CONSTITUTION 


283 


is  in  a  large  measure  dependent  on  the  concentration  as  well  as 
on  the  nature  of  the  inactive  solvent,  and  such  bodies  fre- 
quently cannot  be  brought  into  comparison.  Investigation 
is  largely  limited,  therefore,  to  active  liquid  bodies,  and  even 
here  there  may  be  sometimes  doubts  as  to  their  applicability. 
If,  in  their  preparation,  high  heat  is  applied,  or  a  violent 
reaction  ensues,  a  partial  racemization  of  the  product  is  pos- 
sible, and  in  this  case  too  low  a  result  for  the  rotation  will  be 
obtained.  (See  §  28  and  29.) 

The  reliability  of  the  numerical  value  given  for  the  specific 
rotation,  if  of  a  liquid  substance,  may  be  tested  by  examining 
several  preparations  made  by  different  processes.  In  this 
direction,  Purdie  and  Williamson1  have  carried  out  some 
experiments  with  esters  of  malic  and  lactic  acids,  which  were 
made  : 

1.  By  action  of  alkyl  iodides  on  the  silver  salts  of  the  acids. 

2.  By  esterification  of  a  mixture  of  acid  and  alcohol  by  aid 
of  hydrochloric  or  sulphuric  acid. 

By  using  also  some  observations  of  Walker,2  and  of 
Anschiitz  and  Reitter,3  the  following  results  were  obtained  : 

MALIC  ACID  ESTERS 


Silver  salt 
method. 

Acid  method. 

Purdie  and 
Williamson. 

Ms0 

Purdie  and 
Williamson. 

MS* 

Walker 

M? 

Anschiitz 
and  Reitter. 

M* 

Methyl  malate  ' 
Ethyl  malate  , 
N-Propyl  malate..  . 
N-Butyl  malate  

7.34 
-  12.42 
-  13-70 

—  12.20 

-  10.34 

-  6.85 
-  10.18 
—  11.62 

—    6.88 
-  10.65 
—  ii.  60 
—  10.72 

Ethyl  acetyl   malate 
Ethylbutyryl     " 

-  23.00 
—  22.70 

-  21.58 

-  22.52 

-  22.22 

—  22.60 

1  Purdie  and  Williamson  :  J.  Chem.  Soc.,  69,  818  (1896). 

-  Walker  :  Ibid.,  67,  914  (1895). 

3  Anschiitz  and  Reitter:  Ztschr.  phys.  Chem.,  16,  493  (1895). 


284 


SPECIFIC    ROTATION 

LACTIC  ACID  ESTERS 


Silver  salt  method. 

Acid  method. 

Walker. 

Pnrdie  and 
Williamson. 

Purdie  and 
Williamson. 

-  I3-46 
~  49.87 

-  10-33 

-  49-75 
+  i9-4i 

Ethylacetyl  lactate  

Ethvlchlor  propionate  / 

I         21.78    / 

The  silver  salt  method,  with  the  simple  esters,  gives,  accord- 
ingly, somewhat  higher  values  than  the  acid  method.  The 
lower  rotation  of  the  esters  made  by  the  latter  method  was  not 
due  to  any  racemization,  since  it  was  found  that  the  acids 
separated  from  them  showed  no  lower  rotation  than  those 
originally  employed.  Besides,  in  the  preparation  of  the  above 
esters  no  high  temperatures  were  applied  (not  above  100°); 
in  other  cases  possibly  greater  differences  will  be  noticed. 

As  a  further  cause  of  the  uncertainty  in  the  specific  rotation 
of  liquid  bodies,  possible  changes  in  the  products,  through 
polymerization,  have  been  suggested.  But  as  has  been  shown, 
however,  in  §  62,  the  effect  of  this  reaction  on  the  rotation  has 
not  been  demonstrated  with  complete  certainty.  This  has  been 
confirmed  lately  by  an  observation  made  by  Walden1  on  the 
diamyl  ester  of  itaconic  acid,  as  it  was  found  that  this  sub- 
stance, in  spite  of  gradually  increasing  polymerization,  still 
showed  no  indication  of  any,  or  at  most  of  only  an  unimpor- 
tant change  in  the  optical  activity.  In  different  conditions  this 
compound  gave  the  following  rotations  for  a  layer  i  dm.  in 
length: 

Freshly  prepared,  mobile  liquid  a,t  4.80° 

After  2  months,  thick  liquid,  stringy 4.75 

Completely  hardened,  colorless  #lass 4-75 

To  test  the  relation  between  rotating  power  and  chemical 
constitution,  the  esters  of  active  amyl  alcohol  have  been  fre- 
quently employed.  These  have  all  been  made  from  commercial 
left  rotating  amyl  alcohol  of  different  degrees  of  activity 

1  Walden:  Ztschr.  phys.  Chem.,  ao,  383  (1*96). 


ROTATION  AND  CHEMICAL  CONSTITUTION  285 

(for  example,  [«]/,  =  -  4.5°,  Guye;  --  4.78°,  Walden). 
Such  preparations  always  contain  a  certain,  but  not  deterrmn- 
able,  proportion  of  inactive  isomers,  and  are  comparable 
among  themselves  to  a  limited  extent  only  when  secured  from 
the  same  crude  product.  The  different  isomers  of  the  crude 
amyl  alcohol  appear  to  be  attacked  by  chemical  reagents  to 
not  essentially  different  degrees,  since  Guye  and  Chavanne1 
found  that  the  alcohols  recovered  by  saponification  of  several 
esters,  possessed  a  rotating  power  scarcely  changed  from  that 
of  the  original. 

In  the  following  comparisons  wrhen  bodies  of  different  com- 
positions   are    dealt  with,     the    molecular    rotation,    [J/]  = 

M 

—  r^l,  is  alwavs  employed,  while  for  isomers,  the  value  \oi\ 

100    L 

is  sufficient. 

'       /.   horn  eric  Bodies 

An  idea   of  the  relations  obtaining  here,   may  be  obtained 
from  the  following  observations. 

78.  a.   Metamerism.      Structural  Isomerism 

i .    Trans  location  of  the  Active  Radicals 

Aniylacetic  acid [a~\  ,,  =  -f-    8.53  )  Walden  :  Ztschr.  phys. 

Amylacetate 2.50  )      Chem.,  15,  638. 

Diamylacetic  acid -  18.27  )  Walden  :  Ztschr.  phys. 

Amylamyloacetate 7.01  j       Chem.,  15,638. 

,    \  Guye   and    Chavanne  : 

Methvl  valerate 16.83 

-  a  [      Arch.  phvs.  nat.,  [4], 

Amyl  formate 2.01  | 

'       Jj  54- 

Iii  these  cases  very  marked  differences  appear. 
2.   Alcohol  Radical  Active.     Isomerism  in  the  Inactive  Acid  Radical. 

Amyl  normal  butyrate [^]  D=  —    2-97  ">  Walden  :  Ztschr.  phys. 

Amyl  isobutyrate 2.83  J      Chem.,  15,  638. 

Amyl  normal  brombntyrate- •  •  2.27)  Walden  :  Ztschr.  phys. 

Amyl  isobrombutyrate 2.53  J       Chem.,  15,  638. 

The  differences  in  rotation  are  small. 

j.  Alcohol  Radical  Inactive.  Isomerism  in  the  Active  Acid  Radical. 
Methyl  normal  butyryl  malate  [a]/;  -  22.44  \  Walden  :  Ztschr.  phys. 
Methylisobutyryl  malate —  22.36  J  Chem.,  17,  245. 

1  Guye  and  Chavanne:  Bull.  Soc.  Chim.,  [3],  15,  275  (1896). 


286  SPECIFIC    ROTATION 

Ethyl  normal  butyryl  malate.  .  22.22  )  Walden  :  Ztschr.  phys. 

Ethylisobutyryl  malate  .......  —  21.99  •      Chem.,  17,  245. 

Kthyl-a-brom  'normal  bntyryl  ,  Wa](,en  .  ^^     h 

malate  ....................  24.  76  v 

Ethyl-a-bromisobutyryl  malate  -  22-57  ' 

The  differences  are  likewise  very  small. 
4.     ^4«V  Radical  Active.    I  so  men  sm  in  the  Inactive  Alcohol  Radical 

Normal  butvl  valerate  ........    fa],,  =  +  10.60  )  Guye    and    Chavanne: 

' 


+  10.60  ) 

--10.48 


Isobutvl  valerate 

1454- 

^  Frankland     and     Mac 
Normal  propyl  glvcerate  .....  12.94  T       ™ 

4  \     Gregor:     J.      Chem. 
Isopropyl  glycerate  .........  -  1  1.82  j      ^  ^  ^ 

Normal  butyl  glycerate  ......  —  11.02^  Frankland     and      Mac 

Isobutyl  glycerate  ..........  -14.231      Gregor:      J.      Chem. 

Secondary  butyl  glycerate...  —  10.58)      Soc.,  63,  524. 

Normal  propyl  malate  .......  -  1  1  .62  \  Walden  :  Ztschr.  phys. 

Isopropyl  malate  ............  —  10.41  ^      Chem.,  17,  245. 

Normal  propyl  tartrate  ......  -f-  29.1  1  (  Freundler:  Ann.  chiin. 

Isopropyl  tartrate  ...........  -f  34.83  '      phys.,  [7],  3,  433. 

Normal  butyl  diacetyl  tartrate  8.0   ^  Freundler:  Ann.  chim. 

Isobutyl  diacetyl  tartrate  ----  -f-  17.0    '      phys.,  [7],  3,  433. 

Normal  butyl  dipropionvl  tar-  ^  ^ 

Freundler:  Ann.  chim. 
trate  ......................  -f    6.9    V  ,., 

Isobutyl     dipropionyl  tartrate  -f  11.4    J      P   yS>>  "-7^'  3'  433' 

Normal      butyldibutvryl     tar- 

Freundler:  Ann.  cliim. 
trate  ....................  +    6.0    \ 

Isobutyl  dibutyryl  tartrate...  .-f    8.5    J      P  yS"  L7J'  3'  433- 

The  iso  compounds  show  sometimes  a  higher,  sometimes  a 
lower,  rotation  than  the  normal. 

b.  Position  Isomcrism  in  Benzene  Derivatives 
79-   A   number  of  investigations  have  been  carried  out  to 
determine  the  influence  of  the  o,  m  or  p  positions  of  an  active 
and  inactive  group,  or  of  two  active  groups  in  disubstituted 
benzene  derivatives. 

i.  H.  Goldschmidt  and  Freund1  have  determined  the  specific 
rotation  of  the  following  solid  bodies  from  chloroform  solu- 
tions, the  per  cent,  strength,  p,  within  each  group  being 
nearly  the  same. 

In  some  groups  the  compounds,   C6H3.R,   were  investigated 

1  /tschr.  phys.  Chem.,  14,  394  (1894). 


ROTATION    AND    CHEMICAL    CONSTITUTION  287 

to  determine  the  effect  of  the  addition  of  CH3  by  comparison 

with  C6H4< 

\CH, 

The  differences  show  the  increase  or  decrease  in  molecular 
rotation  from  one  member  to  another. 

/-Amylphenyl  carbaminate -     4. 19  -1-     8.7 

/-Amyl-0-tolyl  carbaminate —   2.66  —     5.9 


m-  "    r ^Jtlx 

>.C5HnJ 


L 

P     5-3  . 

4^NH.COO.C5HUJ         +    4-47  +     9-9 

f /-Menthylphenyl  carbaminate —  77.2    — 212.3 

II.      I  /-Menthyl-0-tolyl  carbaminate —  65.9    —190.4  ~~ 

p=5.6  -          "        m-  ••   r  CH3  H  -  71.4   -206.4  + '  '° 

p-  »    L   "         XH.COO.C10Hj-72.3    -208.9 

Carbanilido-</-carvoxime —  31.7    —  89.9 

III       Carbo-0-toluido-</-carvoxime 27.4     -  81.77 

p   2.7      "   >H-     r         CH,  -1-298-88.83^ 

k     "      p-        L6    *     NH.CO.NO  :  C]nHuJ  -  30.8    +91.6 

Benzoyl-*/-carvoxime —  26.6    -    71.7 

_         ^-Toluyl-^-carvoxime —  27.  i    4-  76.6  ~ 

*~9*m-      "         r  CH,  1   .  ..4-26.Q   -76.0" 

to  10 

.p- 

f0-Broinbenzoyl-f/-carvoxime —  26.0    -f  90.3 

V.  T,_  -,  To  «  —26.8 


TCH  -CH:i                      "I    •••-26'9    "4    76.o  _"- 
L   6         CO.XO:C10HUJ    ..--23.4    -66.3 
Dyl-o'-carvoxime —  26.0    -f-  9°-3 

* %-  J""    "     TCH   Br  -i ...  +  *»  +63-5^;* 

5  !/>-          "  CO.NO  :  C,0H,J 14.9-51.9 


f  0-Nitrobenzoyl-</-carvoxime  .............  inactive 

J  w-         "          r  NO.,  1  ----  20.7    —64.9 


In  general,  the  following  relations  appear  from  these  obser- 
vations : 

a.  With  respect  to  the  influence  of  position,   the  rotation 
increases  in  the  order,    0,  m,  p,  in  groups  I,  II,  and  III,  but 
decreases  in  groups  IV,  V,  and  VI. 

b.  The  introduction  of   a  methyl   group  is  followed  by  a 
decrease  in  rotation  in  I,  II,  and  III,  and  by  an  increase  in  IV. 

2.  The  following  esters  of  ditoluyl  tartaric  acid 
C6H4(CH3)  (C0)0—  CH—  COOH 

C6H4(CH3)(CO)O—  CH—  COOH 


288  SPECIFIC    ROTATION 

have  been  investigated  in  fused  condition   at  different  t  emper- 
atures  by  Frankland  and  Malcolm.1 


Methyl  ester. 

Temp. 

100° 

137° 

,S3° 

^-Compound  .  .  . 
?«-Compound  •  . 

M/>^ 

68.0 
79.0 

II.  0 

61.7 
—  70.6 

8-9 

-52.8 

—  61.0 

8.2 

^-Compound  .  . 

M*- 

102.8 

23.8 

9^-5 

20.9 

-  76.9 

15-9 

Kthyl  ester. 

0-Compound-  .  . 

r^-] 

54-7 

-  50-4 

^/-Compound  .  . 
/-Compound  .. 

M, 
[«]/> 

63.7 
90.0 

9.0 
26.3 

-58-7 
-81.5 

8-3 

22.8 

-69.5 

Here  the  rotation  increases  in  the  order  o,  m,  p,  and  the 
difference  between  o  and  ;;/  is  always  smaller  than  the  difference 
between  m  and  p.  These  relations  remain  true  for  the  differ- 
ent temperatures. 

3.  The  specific  rotations  of  the  following  bodies  have  been 
determined  by  Bin//'  from  chloroform  solutions: 

0-Oxybenzylidenefenchylamine  ( />        2.5) 66.0 

[oil                   -j  6-° 

C"Hl     CH:N.C10HI7J 
0-Methoxybeii/ylidenefenchylaniine     (/>       5 )      59.4 


;C 

LH.  N  :C10 

4.  Walden3  obtained  from  solutions  in  glacial  acetic  acid 
(c  i),  for 

Malic  acid  di-^-toluide  ...............    f"n  ]  —  66.5 

Malic  acid  di-/>-toluide  ...............  —  70.0     ^'* 

Iii  the  majority  of  these  isomers  the  .para  compouiul  appears 
to  have  a  greater  rotation  than  the  ortho. 

But  cases  are  known  in  which  isomeric  bodies  rotate  in 
opposite  directions.  This  is  found'  in 

Propylclibenzoyl  glycerate.  Metliyldiphenylui-tt  \  1  v;l\  cerate. 

CH.,.O.CO.C,  H 


x      / 

>c< 

v.   H   COO/      X>. 


CO.C,H  CH,Coo-        O.CO.CH,.C€H« 

[£r];5      4-21.0  !_«],,          16.1. 

1  J.  Chem.  Soc.,  69,  1309  (1896). 

2  Binz:  Ztschr.  phys.  Chem.,  12,  727  (1893). 
U'al'lt-ii:  X,tM  )ir.  phys.  Chem.,  17. 

*  Frankland  and  MacC'regor:  j    cin-m.  S.K-  ,  69,  104  (1896). 


ROTATION  AND  CHEMICAL  CONSTITUTION  289 


Also  with  the  isomers  in  the  santonin  group,   for  which  there 
was  obtained  from  chloroform  solutions: 

Santonin1  [#]/>=  —171.4° 

Metasantonin -f  1 18.8 

Santonide -f~  744.6 

Metasantonide —  223.5 

Parasantonide -)-  897.3 

c.  Stereoisomeric  Bodies 

80.  A  series  of  observations  carried  out  by  Walden,2  are 
concerned  with  the  active  amyl  esters  of  fumaric  and  maleic 
acids  and  their  derivatives,  /-amyl  alcohol  was  employed  in 
their  preparation. 

Diamyl  ester  of  [/*]/>  \.M~\D             F—M. 

Fumaric  acid8 +  5.93  -f  15.17 

Maleic   acid +4.62  +11.82 

Chlorfumaric  acid3 -j-  5.78  +16.78 

Chlormaleic  acid +4.03  -(-11.70 

Bromfumaric  acid -(-  5.99  -j-  20.07 

Brommaleic  acid -(-  4.58  -f-  15.36 

Methylfumaric  (mesaconic  acid) +5-93  +  16.01 

Methylmaleic  acid    (citraconic  acid.) -j-  4.14  +11.17 

Mean  4.50 

In  all  these  bodies,  it  is  seen  that  the  fumaroid  form  has  a 
molecular  rotation  higher  by  about  4.5  than  the  maleinoid. 

On  the  other  hand,  if  we  consider  compounds  which  are 
related  to  these  types,  but  which  are  saturated  (acids  of  the  suc- 
cinic  series),  according  to  Walden,  the  above  no  longer  holds 
true,  as  seen  in  the  following  : 

Diamyl  ester  of  [**}«  D^]  D  F—M 

/-Dimethylsuccinic   acid —  3.66  —  10.47 

Antisuccinic  acid —3.42  -f    9.79 

Racemic   acid -3-37  Hr    9-77  _  4  06 

Mesotartaric  acid -7-  4.77  -j-  13.83 

i  Carnelutti  and  Nasini  :  Ber.  d.  chem.  Ges.,  13,  2208  (1880). 
-  Walden  :  Ztschr.  phys.  Chem.,  20,  377  (1896). 

3  Earlier  observations  of  Walden  (Ztschr.  phys.  Chem.,  15,638(1894))  gave  the 
following  values  for  these  bodies  : 

Diamyl  esters  of  [<*]/>  \M~\D          Diff. 

Fumaric  acid +  5.69  +  14.56 

Maleic  acid +  4.35  :i.i3 


Chlorfumaric   acid —  5.74  —  16.67 

C 

19 


Chlormaleic  acid    .  /»o  +  13.36 


2QO  SPECIFIC    ROTATION 

But  it  must  be  remembered  here,  however,  according  to  §  18, 
that  a  racemic  acid  ester  of  active  amyl  alcohol  does  not  exist. 
This  is  a  mixture  of  the  amyl  esters  of  d-  and  /-tartaric  acid, 
which  bodies,  since  they  are  not  reflection  images  of  each 
other,  cannot  form  a  racemic  compound. 

77.  Homologous  Series 

81.  The  relations  appearing  here  can  be  seen  from  the  follow- 
ing observations  : 

CHANGES  IN  THE  MOLECULAR  ROTATION  WITH  INCREASE  OF  CH2 

\a\D  [M]D          Diff. 

I.1  Amyl  formate +    2-01  +    2-33       ,         ^ 

Amylacetate    2.53  3.29            °^ 

Amyl  propionate 2.77  3.99 

Amyl  A^-butyrate 2.69  4.25 

Amyl  jV-valerate 2.52  4.33 

Amyl  A^-caproate 2.40  4.46 

Amyl  AMieptylate 2.21  4.42 

Amyl  A^-caprylate 2.10  4.49 

Amyl  AMionylate 1.95  4.44 

Amyl  laurate 1.56  4.21 

Amyl  palmitate . 1.28  4.17 

Amyl  stearate 1.27  4.49 

2. 'Valeric  acid +13.64  +13.91        ,         ^ 

Methyl  valerate 16.83  J9-53             ^'06 

Ethyl  valerate 13.44  17-47                6 

jV-Propyl  valerate u.68  16.82               '  5 

A^-Butyl  valerate 10.60  16. 75 

3.sMethyl  glycerate --    4.80  -    5.76      +    6 

Ethyl  glycerate 9.18  12.30             6'g 

A'-Propyl  glycerate 12.94  19.15      _^_    2'22 

^V-Butyl  glycerate 13-19  21.37 

Heptyl  glycerate 11.30  23.05 

Octyl  glycerate 10.22  22.28      ~    °-77 

4.4Methyl  diacetylglycerate —  12.04  —  24.56 

Ethyl  diacetylglycerate 16.31  35.56           XI'^ 

A^-Propyl  diacetylglycerate ^9-47  45- 1 7 

5.5Methyl   dibenzoylglycerate +26.89  +88.20 

Ethyl  dibenzoylglycerate 26.58  90.90           jg  ,° 

A^-Propy  1   dibenzoylglycerate 2 1 .00  74-76 

Guye  and  Chavanne  :  Compt.  rend.,  lao,  452;  Bull.  Soc.  Chim.,  (3),  15,  275  (1896). 
Guye  and  Chavanne:  Compt.  rend.,  116,  1454  (1893). 
Frank  land  and  MacGregor:  J.  Chem.  Soc.,  63,  1415  (1893). 
Frankland  and  MacGregor:  J.  Chem.  Soc.,  63,  1430. 
Frankland  and  MacGregor:  J.  Chem.  Soc.,  69,  104  (1896): 


ROTATION   AND   CHEMICAL   CONSTITUTION  291 

I.  II.                               III. 

M,  M,              MX, 

6.  Methyl  malate  ..    --    6.85  -    6.88                     -    7.34 

Ethyl  malate ....         10.18  10.65                       12.42 

JV-Propyl  malate        11.62  11.60                       13.70 

jV-Butyl     malate         ••  10.72                       12.20 
Amyl  malate  ...          9.92 
Capryl  malate  ..           6.92 

\M~\  r^/i            fji/i 

L       AD  \-        \  D                    L        J  /? 

Methyl  malate  ..  —  11.10  —  11.15                  —  11.89 

Ethyl  malate. . , .         !9.35    +       5  20.23    +  9^        23.56  +  l1^ 

jV-Propyl  malate        25.32        5'97  25.29   ]                  29.87 

jV-Butyl     malate            ..  26.38    ~  "  ItO9        30.01 
Amyl  malate  ...        27.19 
Capryl  malate  -.24.77 

I.  Formed  by  esterification  from  acid  and  alcohols  by  aid 
of  sulphuric  acid.1 

II.   Produced  in  same  way.2 
III.   By  action  of  the  alkyl  iodides  on  silver  malate.* 

MK  W\* 


Diacetyl  malate  of        I.4            II.3          I.4  II.5 

Methyl — 22.92  —22.86  — 46.76    ,  —46.64 

Ethyl 22.52        22.60       52.25  T*'t?  52.43 

N-Propy}...         22.85        22.68       59.40  ~]  58.96 

JV-Butyl 21.88        19.93        63.01  +  3<t>1  57.38 


M* 

8.6Methyl  ^/-tartrate -f  2.14  +3.8 

Ethyl  rf-tartrate 7.66  15.7 

A'-Propyl  ^-tartrate 12.44  29.0 

9.7Methyl  chlorsuccinate -{-41.42  +74.8 


Ethyl   chlorsuccinate 27.50  57.3 

Ar-Propyl  chlorsuccinate 25. 63  60.6 

^V-Butyl    chlorsuccinate 21.57  57.1 

Amyl  chlorsuccinate 21.56  63.1    2  act.  rad. 

Walden:  Ztschr.  phys.  Chem.,  17,  245  (1895). 

Anschiitz  and  Reitter:  Ztschr.  phys.  Chem.,  16,  493  (1895). 

Purdie  and  Williamson:  J.  Chem.  Soc.,  69,  818  (1896). 

Walden  ;  Ztschr.  phys.  Chem.,  17,  245  (1895). 

Anschiitz  and  Reitter:  Ztschr.  phys.  Chem..  16,  493  (1895). 

M.  A.  Pictet :  Arch.  phys.  nat.,  (3),  7,  82  (1882) 

Walden  :  Ztschr.  phys.  Chem.,  17,  245. 


292  SPECIFIC    ROTATION 

[oi\D 

lo.1  Santonic  acid  .........................    --    70.31  -185.6 

Methyl  santonate  .....................          52-33  T45-5 

Ethyl  santonate  ......................          45-35  132.4           ^  o 

jV-Propyl  santonate  ..................          39-34  120.4 

Parasantonic  acid  ....................          89.51  260.1 

Methyl  parasantonate  ................         108.91  302.8 

Ethyl  parasantonate  ..................          99.98  291.9 

A^-Propyl  parasantonate  ..............          91.27  279.3 

From  chloroform  solutions. 


ii.  Fen  chylamine  (liquid)*  ...............  --    24.89  -    38.0 

Formylfenchylamine  (^  =  3.9)  .......  36-56  66.0 

Acetyl          "                 (fi=--4.6)  .......  46.62  90.7        [  ^ 

Propionyl    "                 (^  =  5.0)  .......  53.16  110.9 

Butyryl         "                 (£  =  1.8)  .......  53.11  118.2 

Determined  from  chloroform  solutions. 

The  following  relations  appear  by  comparing  the  molecular 
rotations  of  the  above  compounds  : 

With  the  homologous  esters,  the  values  of  \_M~\  sometimes 
increase  and  sometimes  decrease  with  increasing  molecular 
weight  of  the  alcohol  radical. 

An  increase  is  found  in  the  esters  of  glyceric  acid  (No  3), 
diacetyl  glyceric  acid  (No.  4),  malic  acid  (No.  6),  diacetyl 
malic  acid  (No.  7),  and  tartaric  acid  (No.  8)  ;  also  with  the 
amyl  esters  of  the  fatty  acids  (No.  i),  and  the  fenchyl  deriv- 
atives (No.  n). 

A  decrease  is  found  with  the  esters  of  valeric  acid  (No.  2), 
santonic  and  parasantonic  acids  (No.  10). 

The  differences  between  the  molecular  rotations  of  two 
neighboring  members  of  a  series,  decrease  in  most  cases 
regularly  (Nos.  i,  2,  4,  6,  n)  ;  the  effect  of  the  gradually 
increasing  molecular  weight  of  the  alcohol  radical  becomes 
therefore,  constantly  less. 

From  a  certain  molecular  weight  on,  the  influence  seems  to 
be  exerted  in  the  opposite  direction,  so  that  the  increase  is 
changed  to  a  decrease,  from  which  it  follows  that  in  the  homol- 
ogous series  a  member  is  found  which  possesses  a  maximum 
rotation. 

»  Carnelutti  and  Nasini  :  Ber.  d.chem.  Ges.,  13,   2208  (1880). 
2  Binz  :  Ztschr.  phys.  Chem.,  12,  731   (1893). 


ROTATION   AND   CHEMICAL   CONSTITUTION  293 

The  geatest  change  is  found  in  going  from  the  acid  to  the 
first  ester  (Nos.  2  and  10). 

In  Nos.  5  and  9  the  rate  of  change  is  irregular. 

///.    The  Effect  of  Linkage  of  the  Carbon  Atoms. 

The  experimental  results  on  this  are  as  follows  : 
a .    Change  from  Single  to  Double  Bond  by  Loss  of  2  Atoms  of  H. 

82.  The  changes  of  rotation  in  cases  of  this  kind  have  been 
investigated  by  Walden1  in  a  series  of  liquid  esters  of  active 
amyl,  CH(CH3)(C2H5)— CH2— ,  in  the  preparation  of  which 
left-rotating  amyl  alcohol  was  used. 

C3HU  =  A.  \0\D         [M]D       Diff. 


Amyl  w-butyrate      CH3— CH2— CH2— CO2A  +  2.81     +    4.43-      ^  i 
Amyl  crotonate        CH3— CH^CH— CO2A     +4.24     +    6.62 

CH3— CH— CO,  A 

Amyl  isobutyrate  +3.10    +    4.90 

CH, 

CH2=C— C02A 
Amyl  methacrylate  +  3.51     +    5.47 


fCH,— COXA 
Diamyl  succinate  +3-76  +  9.71 

CH2-C02A 
CH— C02A 

|  Diamyl  fumarate  T-  5.93     +  15-^7 

L  CH— CO,A 

CH2— CO,A 
Diamyl  chlorsuccinate  |  -h  3-75  +  10.98 

CHC1— CO2A 

CH-C02A 
Diamyl  chlorfumarate  +5.78  +16.78 

C  Cl— CO2A 

CH2— CO,A 
Diamyl  methylsuccinate  |  +3.76+9.99 

CH.CH3— COjA 

CH— CO,  A 
Diamyl  mesaconate  +  5.93  +  16.01 

C.CH:i— CO2A 

f  CH2— CO,A 

Triamyl  tricarballylate      CH — CO2A  +  4.01     +  15.48 

CH2-CO,A 
CH-C02A 

I! 

Triamyl  aconitate  C— CO, A  +  6.16     +  23.66 

I  CH2CO2A 

1  Walden  :  Ztschr.  phys.  Chem.,  20,  569  (1896). 


294  SPECIFIC    ROTATION 

C6Hn  =  A  [>]/>  z>       DiflF. 

|A     *J53£*    '    C6H5-CH2-CH2-C02A  +  2.26     +    4.98   ^ 
1  Amyl  cinnamate      C6H5— CH=CH— CO,A      +  7.51     -f  16.36   ^'^ 

In  all  these  cases  it  is  seen  that  the  change  from  single  link- 
age of  carbon  atoms  to  double  linkage  is  followed  by  an 
increase  in  the  rotating  power. 

b.  Change  from  Double  to  Triple  Bond  between   Carbon  Atoms. 

83.  For  this  case,  we  have  as  yet  only  the  following  illus- 
tration, likewise  from  Walden  : l 

M/>        \M\D    Diff. 

(  Amyl  cinnamate  C6H5— CH=CH -CO2A  -j-  7.51  +  16.36 

\Amyl  phenylpropiolate    C6H5— C=C— CO2A        -f  5.58  -f  12.05  4'3* 

Here  a  decrease  in  activity  follows. 

c.  Change  from  a  Chain  Carbon  Compound  to  a  Cyclic   Com- 

pound. 

84.  As  van't  HofF  first  showed,  the  ring  structure  exerts  a 
very  considerable  influence  on  the  degree  of  rotation,  and  it 
may  even  change  its  sign. 

Accurate  numerical  data  are  here  hard  to  obtain,  as  most  of 
the  compounds  which  could  be  considered  are  solid,  and  their 
specific  rotations,  therefore,  variable  with  the  solvent  and  con- 
centration. The  relations  which  may  obtain  may  be  seen 
from  the  following  comparison  of  two  dicarboxylic  acids  with 
their  cyclic  anhydrides: 


f  water                 c  = 

Diacetyl  tartaric  acid          J  water                 e  = 
j  ethyl  alcohol   c  = 

[  ethyl  alcohol  c  = 
f  acetone             c  = 

Diacetyl  tartaric  anhydride  \  . 

*.  benzene            c  = 
Dibenzoyl  tartaric  acid        f  ethyl  alcohol    c  = 
(  anhydrous  )               \  methyl  alcohol  c  = 

Dibenzoyl  tartaric  anhy- 
acetone              c  = 
dnde3 

17.95 

7.37 
3-27 
11.66 
4.40 
2.09 
1.05 
4.76 
4.63 

4-64 

M*  =  - 
teU- 

M*-  + 

23.0 
19.3 
23.6 
21.5 

59-7 
62.0 

58.7 
63.1 
117.7 

122.  1 
1429 

1  Walden  :  Loc.  eit. 

*  van't  Hoff  :  "Mgerung  der  Atome  im  Raumc,"  1894,  p.  109. 

»  M.  A.  Pictet  :  Jahresbericht,  1882,  p.  856. 


ROTATION   AND    CHEMICAL   CONSTITUTION  295 

In   both   of  these   cases   the   rotation  of  the  anhydride  is 
greater  than  that  of  the  acid,  and  of  opposite  direction. 
But  another  condition  appears  with  the  following  bodies  :l 

acetic  ether      c  =  10          [a~]  n  =  +  52.7 
Chlorsuccmic  acid2  L"J  D 

acetic  ether      c  =    6.66  -f  52.9 

acetic  ether      c  =  10         [oH     = 
Chlorsuccmic  anhydride        acetic  ether      c  =    5 

In  this  case  the  rotation  of  the  anhydride  is  smaller  than 
that  of  the  acid,  but  in  the  same  direction. 

If  we  compare  the  lactone- form  ing  acids  of  the  sugar  group 
with  the  lactones  themselves,  it  is  found,  as  pointed  out  in 
§  75,  that  the  latter  have  always  much  the  stronger  activity. 
As  the  true  rotating  power  of  the  acid  can  not  be  determined 
with  certainty  because  of  the  existence  of  multirotation, 
Alberda  van  Ekenstein,  Jorissen  and  Reicher3  have  investi- 
gated the  neutral  alkali  salts,  which  do  not  show  multirotation, 
and  from  which  the  rotation  of  the  acid  ion  may  be  obtained. 
The  lactones  were  tested  as  soon  as  possible  after  solution  so 
as  to  avoid  the  effects  of  multirotation.  In  the  experiments  the 
concentration  of  the  acid  ions  was  from  2  to  6.5  grams  in  100 
cc.  and  of  the  lactones  from  4  to  10  grams.  With  addition 
of  a  few  data  from  Fischer,  Tollens,  and  others,  the  authors 
mentioned  give  the  following  table.4 

\_M~\D 

, • .       Change  in 

Acid  ion.       I«actone.       rotation. 

Ribonic  acid -+-    2°  -    30°          32° 

</-Gluconic  acid  -f-i6  -f-n6  100 

/-Man  n  on  ic  acid -f-  20  —    97  117 

</-Gulonic  acid —27  -j-    99  126 

/-Gulonic  acid -f-  27  -    99  126 

Saccharonic  acid —  1 1  -f~  152  163 

Isosaccharonic  acid —  n  +102  113 

<f-Saccharic  acid +26  +77            51 

Mannosaccharic   acid -J-    2  -)-  3545  352 

a-Rhamnohexonic  acid -f-  13  -j-  163  150 

a-Glucoheptonic  acid +  16  —112  128 

1  Walden  :  Ztschr.  phys.  Chem.,  17,  245  (1895). 

5  Chlorsuccinic  acid  dissolved  in  water  has  a  much  smaller  rotation  than  in  acetic 
ether.  Walden  (Ber.  d.  chem.  Ges.,  26,  215)  gives  these  values: 

Water c  =  16  [a]  =  -f  20.6 

c  =    6.4  +  20.8 

c  =    3.2  +  21.3 

3  Ztschr.  phys.  Chem.,  ai,  383  (1896). 

4  The  table  contains  the  mean  values  of  the  numbers  given  in  the  original  paper. 

5  This  refers  to  the  double  lactone, 


296  SPECIFIC   ROTATION 

The  rotating  power  of  the  cyclic  lactones  is  thus  seen  to  be 
much  stronger  than  that  of  the  acid  ion  and  often  in  the 
opposite  direction.  The  change  of  rotation  is  mostl}'  from 
100°  to  150°,  but  the  numbers  disclose  no  characteristic 
regularities. 

In  carbocyclic  and  heterocyclic  compounds  high  rotating 
power  is  generally  found,  especially  when  these  compounds 
contain  several  asymmetric  carbon  atoms,  as  is  the  case  in  the 
bodies  of  the  santonin  group  and  in  the  alkaloids,  for  example  :] 

w- 

Limonene-a-nitrosochloride  in  chloroform ±  314° 

Ivimonene-/3-nitrosochloride  in  chloroform ±241 

Sodium  nitrocamphor  in  water -f  233 

Metasantonide  in  chloroform —  224 

Santonide  in  chloroform +  745 

Parasantonide  in  chloroform -\-  897 

Quinidine  in  alcohol -f-  255 

Thebaine  in  alcohol : —  219 

Cupreine  sulphate  in  water —  290 

But,  on  the  other  hand,  some  cyclic  bodies  possess  a  low 
rotating  power,  as  : 

M, 

Tetrahydronaphthylenediamine  hydrochloride  in  water 7.5° 

Benzoylhydrochlorcarvoxime  in  acetic  ether -j-    9.9 

Aconitine  in  alcohol -f-  i i.o 

Cinchonicine  in  water -j-  28.7 

Cocaine  in  chloroform -  16.3 

Conine,  liquid -{-  18.3 

High  rotation  is  found  also  in  bodies  which  are  not  cyclic,  as  : 

Cystin  in  hydrochloric  acid -  205.9 

o-Phenylchloracetylchloride  in  carbon  disulphide -f  158.3 

d.  Compounds  with  Several  Asymmetric  Carbo?i  Atoms. 
85.  Summation  of  the  Rotating  Power  of  Active  Groups.  Optical 
Superposition. — In  his  original  statement  of  the  doctrine  of 
asymmetric  carbon  atoms,  van't  H off2  made  the  assumption 
that  in  compounds  which  contain  several  asymmetric  groups, 
the  optical  effect  of  each  one  is  not  changed  by  the  presence 
of  the  others,  and  the  rotation  of  the  whole  is  equal  to  the  alge- 

1  For  the  seferences  to  the  literature  see  the  chapter  on  constants  ,,{  rotation. 
*  van  't   Hoff  :  Hull.   Soc.   Chim.,  [2],  33,  298   (1875)  ;   "  L,agenmg  der  Atome  im 
Raume,"  2nd  ed.  p.  120. 


ROTATION   AND    CHEMICAL   CONSTITUTION  297 

braic  sum  of  the  group  rotations,   as  these  may  have  opposite 
signs. 

The  correctness  of  this  assumption,  which  lies  at  the  founda- 
tion of  all  discussions  on  optical  isomerism,  has  received  experi- 
mental proof  recently  through  work  of  Guye  and  of  Walden. 
These  chemists  made  isomeric  liquid  amyl  esters,  partly  from 
active,  partly  from  inactive  components,  in  the  following  three 
combinations  : 

I.  From  active  acid  and  inactive  alcohol. 
II.  From  inactive  acid  and  active  alcohol. 

III.  From  active  acid  and  active  alcohol. 

Ester  III  contains  the  asymmetric  groups  of  I  and  II 
united,  and  the  sum  of  the  specific  rotations  of  I  and  II  must 
equal  the  specific  rotation  of  III. 

As  the  following  experiments  show  this  condition  actually 
obtains.  In  the  preparation  of  esters  of  inactive  acids  or  of 
inactive  amyl  alcohol,  the  racemic  forms  of  these  compounds 
were  used.  (On  the  racemization  of  amyl  alcohol  see  §  28.) 

AMYL  LACTATES.1  [or]  D 

I.  z-Ainyl  /-lactate -  6.38° 

II.  /-Amyl  z-lactate +  2.64 

III.  /-Amyl  /-lactate • -  3.93 

I  +  II  =  -  3.74 
AMYL  VALERATES.* 

I.  /-Amyl  </-valerate otD  for  /  =  0.5  dm  =  J-  4.40° 

II.  /-Amyl  z'-valerate +  1.22 

III.  /-Amyl  </-valerate +  5-32 

I  +  II  =  4-  5.62 

AMYL  «-OxYBUTYRATES.s  [**]/> 

I.  /-Amyl  /-oxybutyrate -  8.5° 

II.  /-Amyl  /-oxybutyrate -f-  1.5 

III.  /-Amyl  /-oxybutyrate -  7*3 

I  +  II  =  -  7.0 

AMYL  AMYLACETATES/  [ar]  D 

I.  /-Amyl  </-amylacetate H-  4-36° 

II.  /-Amyl  /-amylacetate +  1.54 

III.  /-Amyl  rf-amylacetate +  5-64 

i  +  n  =  +  5.90 

1  Walden  :  Ztschr.  phys.  Chem.,  17,  721  (1895). 

-  Guye  and  Gautier  :  Compt.  rend.,  119,  953  (1894). 

3  Guye  and  Jordan  :  Compt.  rend.,  120,  632  (1895). 

4  Guye  :  Compt.  rend.,  121,  827  (1895). 


298  SPECIFIC   ROTATION 

AMYI,   PHENYI.CHI.ORACETATES.1  [«]  D 

I.  /-Amyl  rf-phenylchloracetate +  23.31  ° 

II.  /-Amyl  /-phenylchloracetate +    3.23 

III.  /-Amyl  </-phenylchloracetate +26.79 

I  +  II  =  +  26.54 

AMYL  MANDEI.ATES.2  \_a~\r> 

I.  /:Amyl  /-mandelate —  96.46° 

II.  /-Amyl  /-mandelate -j-    2.76 

III.  /-Amyl  /-mandelate —  94.02 

I  +  II  =  -  93.70 

DlAMYI,  CHI,ORSUCCINATES.3  \_a~\D 

I.  /-Amyl  rf-chlorsuccinate -f  21.56° 

II.  /-Amyl  /-chlorsuccinate -f-    3.75 

III.  /-Amyl  </-chlorsuccinate —  25.15 

I  +  II  =  +  25  31 

DlAMYI,  AMYI.MAI.ONATES.4  [a~\  D 

I.  /-Amyl  </-amylmalonate -j-    6. 10° 

II.  /-Amyl  /-amylmalonate -f    3.48 

III.  /-Amyl  rf-amylmalonate -f-    9.65 

1  +  11  =  4-   9.58 

DlAMYI,   MAI.ATES.5  \_U~\D 

I.  /-Amyl  /-malate 9-92° 

II.  /-Amyl  /-malate +    3.50 

III.  /-Amyl  /-malate —    6.88 

I  +  II  =     -    6.42 

DIAMYI,  TARTRATES.           M/>6  [XU7 

I.  /-Amyl  </-tartrate +14.10°  +  14.67° 

II.  /-Amyl  /-tartrate +    3.37  +    3.38 

III.  /-Amyl  f/-tartrate +  17.73  +  18.61 

I  +  II  =  +  17.47  +  18.05 

DlAMYL    DlVALBRYI,  TARTRATES.8 

(Six  Asymmetric  Carbon  Atoms.)  [a]/> 

I.  /-Amyl  /-valeryl  /-tartrate +    2.44° 

II.  /-Amyl  d- valeryl  /-tartrate +    3.48 

III.  /-Amy  1  /-valeryl  rf-tartrate +    6.42 

IV.  /-Amyl  </-valeryl  (/-tartrate +  11.32 

I  +  II  +  III  =  +  12.34 

Walden  :  Ztschr.  phys.  Chem.,  17,  722  (1895). 

Walden  :  Ztschr.  phys.  Chem.,  17,  721  (1895). 

Walden  :  Ztschr.  phys.  Chem.,  17,  723  (1895). 

Guye  :  Compt.  rend.,  lai,  827  (1895). 

Walden  :  Ztschr.  phys.  Chem.,  17,  722  (1895). 

Walden  :  Ztschr.  phys.  Chem.,  17,  723  (1895). 
1  Guye:  Compt.  rend  ,  123,  932  (1896). 
8  Guye  and  Goudet :  Compt.  rend.,  laa,  932  (1896). 


ROTATION   AND   CHEMICAL   CONSTITUTION  299 

Finally,  optical  superposition  may  be  recognized  in  the 
following  bodies  also,  if,  on  account  of  differences  in  compo- 
sition, the  molecular  rotation  [J/],  be  made  the  basis  of  com- 
parison :  [^/]/>l 

I.  Amyl  acetate +    3.25° 

II.  Amyl  acetic  acid +  1 1.08 

III.  Amyl  amylacetate +  14.02 

I  +  II  =  +  14.33 

The  great  differences  which  appear  in  the  specific  rotations 
of  the  isomeric  sugars,  for  example  in  the  hexoses,  or  in  the 
hexonic  acids,  depend,  undoubtedly,  as  van't  Hoff2  suggested, 
on  the  summation  of  the  effects  of  the  four  asymmetric 
groups  contained  in  them,  the  rotations  of  which  are  unequally 
strong  and  in  opposite  directions.  Observations  are  not  yet 
sufficiently  numerous  to  establish  the  values  of  the  group 
rotations,  not  even  for  the  ions  of  the  lactone-forming  acids 
given  some  pages  back. 

IV.  Dependence  of  the  Rotatory  Power  of  an  Active   Atomic 

Complex  on  the  Masses  of  the  Four  Radicals  Joined 

to    the    Asymmetric   Carbon  Atom. — 

The    Hypothesis    of   Guye. 

86. — An  attempt  to  determine  the  amount  and  direction  of 
rotation  from  the  composition  of  an  active  molecule  was  made 
in  1890,  simultaneously  by  Ph.  A.  Guye3  and  Crum  Brown,4 
a  consideration  of  the  tetrahedral  form  of  the  asymmetric 
complex,  and  the  relative  masses  of  the  four  groups  being  the 
common  starting  point  in  the  discussion.  The  problem,  which 
was  handled  in  detail  and  brought  into  mathematical  form 
especially  by  Guye,5  was  well  calculated  to  arouse  great 
interest,  and  it  has  been  the  incentive  in  the  undertaking  of 
numerous  investigations. 

The  hypothesis,  as  stated  by  Guye6  in  1893,  *n  general  form 
is  as  follows : 

Walden  :  Ztschr.  phys.  Chem.,  15,  638  (1894). 

van't  Hoff  :  "  I^agerung  der  Atome  im  Raume,"  ad  ed.  p.  120. 

Guye  :  First  paper:  Compt.  rend.,  no,  714  (1890). 

Crum  Brown  :  Proc.  Roy.  Soc.  Edin.,  17,  181  (1890). 

Guye  :  Compt.  rend,  in,  745  (1891)  ;  114,  473  (1892)  ;  116,  1133,  1378, 1451,  1454  (1893); 
119,  906  (1894)  ;  lao,  157,  452,632,   1274  (1895).     These:  Paris,   1891.     Conferences  de  la 
Soc  Chim.,  Paris,  1891,  p.   149.     Arch.  sc.  phys.  nat.   [3]  a6,  97,  201,  333  (1891).     Ann. 
chim.  phys.,  [6],  35,  145  (1892).     Bull.  Soc.  Chim.,   [3],  9,  403  (1893). 
6  Guye  :  Compt.  rend.,  116,  1378,  1451. 


300  SPECIFIC    ROTATION 

As  a  measure  of  the  amount  and  sign  of  the  rotating  power 
of  an  active  molecule,  the  so-called  product  of  asymmetry,  P, 
may  be  taken,  which,  in  general,  may  be  defined  as  equal  to  the 
product  of  the  six  perpendiculars  from  the  center  of  gravity  of 
a  tetrahedron  to  the  six  planes  of  symmetry  of  the  original 
regular  tetrahedron.  According  to  the  orientation  of  the  four 
groups  combined  with  the  asymmetric  carbon  atom,  Pis  found 
in  different  ways  : 

i  .  If  the  tetrahedron  is  regular  and  the  radicals  are  found 
exactly  at  the  angles  of  the  same,  the  product  of  asymmetry 
depends  only  on  the  masses  of  the  four  groups,  a,  b,  c,  and  d\ 
that  is,  on  their  formula  weights.  In  this  case,  the  following 
expression1  is  found  for  P. 


in  which  the  constant  factor  (/.  sin  a)*  may  be  dropped.2 

2.  The  masses,   a,  b,  c,  and  d  may  be  situated  at  different 
distances,  /,  m,  n,   and  /,   from  the  center  of  gravity  of  the 
original    tetrahedron,    but    always    in    the  direction    of  the 
straight  lines  from  the  center  to  the  four  angles. 

3.  The  masses  a,  b,  c  and  d  are  found  at  different  distances, 
/,  m,  n  and/  from  the  center  of  the  original  tetrahedron,   and 
further,    on   account   of  their   mutual  attractions,  they  have 
undergone  lateral  displacements,  so  that  the  straight  lines,   /, 
m,  n  and  p  form  different  angles  with  each  of  the  original 
planes  of  symmetry  (ael  ...  a6  for  /  ;  /?,  ...  /?,.  for  m  ;  yl  •  .  .  y6 
for  w  ;£,...  <56  for/). 

The  complicated  formulas3  for  P  in  case  2  and  the  perfectly 
general  case  3  can  not  be  used  for  calculations  because  they 
contain  undeterminable  quantities  (/,   m,  n,  p  at.  .  .  /?.  .  .  y  .  .  . 
6).     We   are,    therefore,    limited   to   formula    I,    under   the 
assumption  that  the  displacing  influences  mentioned  in  cases 
2  and  3  are  too  small  to  cause  appreciable  disturbances. 
The  above  equation  satisfies  the  conditions,  that  : 
a.  The  product  P  must  be  zero  when  two  or  more  of  the 

1   For  the  derivation  of  the  formula,  the  original  paper  must  be  consulted. 
•  In  this,  /  is  the  distance   of  the   four  masses  from  thecenterof  the  tetrahedron, 
and  a  is  the  angle  54°  44'. 
8  See  the  original  paper. 


ROTATION   AND    CHEMICAL   CONSTITUTION  301 

masses,  a,  b,  c,  and  d  are  equal  ;  that  is,  when  the  asymmetry 
of  the  molecule  is  destroyed. 

b.  The  product  must  be  the  same  but  of  opposite  sign  when 
two  of  the  values  a,  b,  c,  and  d  are  transposed,  the  one  for  the 
other.  Such  a  change  corresponds  to  the  conversion  of  the 
right-rotating  form  of  a  body  into  the  isomeric  left-rotating. 

Changes  in  the  rotating  power  must  follow  parallel  with 
changes  in  the  product,  P,  corresponding  to  variations  in  the 
weights  a,  b,  c,  and  d.  If  the  order  of  the  weights  of  the 
groups  is  as  follows  : 

a>b>c>d 

and  a  is  replaced  gradually  by  smaller  and  smaller  values,  then, 
if  the  original  body  be  assumed,  for  illustration,  as  right- 
rotating,  the  following  conditions  are  to  be  expected  : 

1 .  As  long  as  a  >  b  there  must  be,  according  to  the  numeri- 
cal relation  between  them,  either  a  continuous  decrease  in  the 
right   rotation,  or  at  first  an  increase,  and  then  after  passing 
a  maximum,  a  decrease  in  the  rotation. 

2.  a  =  b.     Condition  of  inactivity. 

3.  a  <  b.     Change  to  increasing  left  rotation  to  a  maximum, 
then  a  decrease. 

4.  a  =  c.     Second  condition  of  inactivity. 

5.  a  <  c.  Appearance  of  right  rotation,   which  increases  to 
a  maximum  and  then  decreases. 

6.  a  =  d.  Third  condition  of  inactivity. 
^7.  a  <  d.   Increasing  left  rotation. 

In  the  experimental  examination  of  these  provisions,  they 
seemed  at  first  to  be  confirmed.  Thus,  it  was  possible  to  show 
in  some  homologous  series  the  complete  or  nearly  complete 
coincidence  of  a  maximum  point  in  rotation  with  a  maximum 
point  in  the  product  of  asymmetry,  as  is  illustrated  by  the 
following  table  of  Guye  and  Chavanne1  based  on  observations 
by  Frankland  and  MacGregor2  on  the  rotation  of  esters  of 
/-glyceric  acid.  The  value  of  the  product  of  asymmetry,  P, 
is  shown  in  parallel  column,  and  multiplied  by  io6  to  give  con- 
venient numbers  for  comparison. 

1  Guye  and  Chavanne  :  Compt.  rend.,  116,  1454. 

2  Frankland  and  MacGregor:  J.  Chem.  Soc.  63,  524  (1893). 


302 


SPECIFIC    ROTATION 


Glycerate  of 

* 

C(COOR).    (CH2OH.) 

(OH.) 

d 

(H.) 

OL. 

LM]D. 

P.   10.6 

JV-Butyl  .  .  . 

ioi              31 

17 

I 

—  II.021 

-  17.9 

347 

AT.propyl.. 

8?                  31 

17 

I 

-  12.94! 

-  19.2 

358 

Ethyl  

73             31 

17 

I 

-  9.18 

-  12.3 

345 

Methyl  .... 

59             31 

17 

I 

-  4.80 

-  5.8 

289 

A  very  near  coincidence  in  the  maximum  points,  with  a  dis- 
placement of  only  one  term,  is  shown  in  the  following  valeric 
esters  investigated  by  Guye  and  Chavanne.2 


Valerate  of 

C(COOR). 

(C,H6.) 

(CH3.) 

d 

(H.) 

M*. 

[<U 

P.  I0«. 

JV-Butyl... 

IOI 

29 

15 

H-  10.60 

+  16.75 

351 

N-Propy}.. 

87 

29 

15 

11.68 

16.82 

364 

Ethyl  

73 

29 

15 

13-44 

17.47 

374 

Methyl.... 

59 

29 

15 

16.83 

19.53 

332 

Valeric  acid 

45 

29 

15 

13-64 

13.91 

218 

Also  when  the  specific  rotations  of  the  amyl  esters  of  the 
fatty  acids  are  compared  with  their  products  of  asymmetry  we 
find:3 


M* 

P.  I0«. 

4-  i  c6 

JAA 

I  O* 

*••?!) 
2  IO 

22Q 

221 

•*z<7 

2*8 

•*0° 
280 

2  *2 

209 

121 

••o* 

2  60 

3*L 
1*1 

2.09 

2  77 

35  l 

171 

+•11 
2  c\ 

J/o 

17A 

*-o6 

O/'t 

332 

Numerous    other    investigations     of     these     relationships 

1  Frankland  and  MacGregor  gave  later  the  corrected  values  for  Ar-butyl  glycerate 
««•—  13.19°  and  [M]/>  =—  21.4°  (J.  Chem.  Soc.,  63,  1417),  which  makes  this 
example  unsuitable  for  confirmation  of  the  hypothesis. 

1  Guye  and  Chavanne :  Compt.  rend.,  116,  1454. 

»  Guye  and  Chavanne:  Compt.  rend.,  119,  906.  If  the  values  of  the  molecular 
rotation  \M\  be  taken,  the  maximum  is  then  found  at  amyl  caprylate,  that  is,  far 
removed  from  the  maximum  of  the  product  of  asymmetry. 


ROTATION   AND    CHEMICAL   CONSTITUTION 


303 


in  which  besides  Guye,1  many  chemists, 2  and  especially 
Walden3  have  taken  part  led  gradually  to  the  discovery  of 
numerous  facts  which  can  not  at  all  be  reconciled  with  the  re- 
quirements of  the  hypothesis.  The  following  discrepancies, 
especially,  were  brought  out : 

i.  Compounds  in  which  two  of  the  groups  a,  b,  c,  and  d,  have 
the  same  weight,  and  which,  accordingly,  should  be  inactive, 
often  possess  a  strong  rotating  power. — Walden4  gives  many 
cases,  for  example  : 


M, 

["]» 

a                      bed 

CfCH    COOCH  ^  (CO  OCH  WO  C  H  O^  (H^ 

.£    0 

73                        59                59                    i 
Methyl  acetylmandelate 
C(C  H  ^  (CO  OCH  ">  fO  C  H  O^  (FH.. 

—  22.9 
—  146  J. 

—  4"-° 

—   3Od  5 

77              59                 59              i 
Ethyl   propionylmandelate 
C(C  TT  ^  (CO  OC  H  "1  CO  C  H  O\  CR\    . 

—  117  7 

268  -; 

77             73                   73            i 
Dimethyl   propionylmalate 
C(CH    CO  OCTT  ^  (CO  OCH  WO  C  H  O^  (H^ 

—  22  Q 

CQ   O 

73                      59                      73            i 
Dipropyl   isovalerylmalate 
C(CH    CO  OC  H  1  (CO  OC.H,")  (O  C-H«O^  (H")  .. 

£..     - 

101                          87                   101              i 

21.7 

05-5 

2.  A  change  in  the  order  {transposition}  of  two  group  weights, 
which,  according  to  the  theory,  should  be  accompanied  by  a  change 

1  Guye  has  introduced  another  constant  of  rotation  in  addition  to  the  specific  and 
molecular  rotation,  and  expresses  it  by  the  formula 

rj,          a     3       77 

[6]=~r  A -5-, 

in  which  a  is  the  observed  angle  of  rotation,  /  the  length  of  column,  M  the  molecular 
weight,  and  d  the  density  of  the  substance.  Aignan  criticized  the  applicability  ot  the 
formula  (Compt.  rend.,  120,  723). 

2  l,e  Bel  :  Compt.    rend.,    114,   304;    119,   226.     Bull.   Soc.   Chim.,    [3],    7,  613,   801. 
Colson  :  Compt.  rend.,  114,   175,  417;    115,729,  948;   116,  319,  818  ;  119,  65;   lao,   1416. 
Bull.  Soc.  Chim.,  [3],  7,  802;  9,  i,  87,  195.     Friedel  :  Compt.  rend..    115,  763,  994  ;  116, 
351.     Freundler  :  Compt.  rend.,  115,  509,  866  ;  117,   556.     Bull.  Soc.  Chim.,  [3],  7,  804  ;  9, 
409,680;  n,  305,  366,468,  470,  477.     Ann.  chim.  phys.   [7],  3,  487.     Simon:  Bull.  Soc. 
Chim.,   [3],  lif    760.     Purdie  and    Walker  :  J.   Chem.    Soc.,   63,  240.     Frankland  and 
MacGregor  :  J.  Chem.  Soc.,  63,    1416,   1430;  65,  750.    Piutti :    Gazz.  chim.,  a4,  II,  85. 
Binz   :  Ztschr.    phys.  Chem.,    la,    733.    Goldschmidt  :    Ztschr.  phys.  Chem.,   14,  394 
Wallach  :  Ann.  Chem.  (t,iebig),  376,  316,  322. 

8  Walden  :  Ztschr.  phys.  Chem.,  15,  638  ;  17,  245,  705. 
*  Walden  :  Ztschr.  phys.  Chem.,  17,  245,  712  (1895). 


304 


SPECIFIC    ROTATION 


in  the  direction  of  rotation,   often  is  not  followed  by  this  effect. — 
Thus,  we  have  according  to  Walden:1 


t               Substance. 

Order  of  the 
weights  of  the 
groups. 

Direction  of 

rotation  of  the 
substance. 

Sign  of  the 
product  of 
asymmetry.  | 

Mandelic  acid 
C(C6H5)(CO.OH)(OH)(H) 

(i  b  c  d 

4_ 

i 

Amyl  mandelate 
C(C6H5)(CO.OC5HH)(OH)(H) 

i 

Acetylmandelic   acid 
C(C6H5)(CO.OH)(O.C,H30)(H) 

d  c  b  d 

1 
_L 

Dipropyl  acetylmalate 
C(CH2.CO.OC3H7)(CO.OC3H7)(O.C,H30)(H) 
101                      87                   59             i.. 
Dipropyl  chloracetylmalate 
C(CH2.CO.OC,H7;(CO.OC,H7)(O.C.2H2C10)(H) 
101                     87                   93.5            (i) 

abed 
a  c  b  d 

+ 
+ 

J_ 

On  the  other  hand,  by  transposition  of  the  group  weights  a 
change  may  follow  in  the  direction  of  rotation,  while  the  sign 
of  the  product  of  asymmetry  remains  the  same.  For  example  : 


Substance. 

1 

Direction  of 
rotation  of  the 
substance. 

Sign  of  the 
product  of 
asymmetry. 

Mandelic  acid 
C(C6H6)(CO.OH)(OH)(H) 

11                 AZ                17          I   .  . 

i 

77             45            »7       *  • 

Phenylbromacetic  acid 
C(C8H5)(CO.OH)(Br)(H) 

c  d  b  d 

1 

Phenylbromacetyl  bromide 
C(CBH5)(CO.Br)(Br)(H) 

b  c  d  d 

Dimethyl  malate 
C(CH2.CO.OCH8)(CO.OCH3)(OH)(H) 

d  b  c  d 

4_ 

Dimethyl  bromsuccinate 
C(CH,.CO.OCH3)(CO.OCH,)(Br)(H) 

c  a  b  d 

4- 

i  Walden  :  Ztschr.  phys.  Chem.,  17,  705.  The  compounds  were  made  from 
/-mandelic  acid  and  had,  therefore,  a  direction  of  rotation  the  opposite  from  that 
given  in  the  table.  The  same  is  true  of  the  ester  of  malic  acid. 


ROTATION   AND    CHEMICAL   CONSTITUTION  305 

j.  In  homologous  series  the  changes  in  rotatory  poiver  and 
product  of  asymmetry  are  not  parallel  in  the  majority  of  cases , 
but  subject  to  manifold  deviations. 

From  all  these  considerations  it  has  become  evident  that  the 
principles  on  which  the  product  of  asymmetry  is  based,  are 
not  satisfactory.  It  is  clear,  as  Guye1  also  admits,  that  it  is 
not  alone  the  masses  of  the  four  groups  which  exert  the 
influence,  but  also  their  relative  positions,  the  actions  which 
they  have  on  each  other,  their  configurations,  and  finally  the 
nature  of  the  elements  themselves  which  are  important  in 
determining  the  direction  and  extent  of  rotation.  On  account 
of  this  complexity  in  the  phenomenon,  it  is  unlikely  that,  even 
through  other  means,  will  it  ever  be  found  possible  to  discover 
the  numerical  relations  between  amount  of  rotation  and  atomic 
structure  of  the  molecule. 

1  Guye  and  Chavanne  :  Bull.  Soc.  Chim.,  [3],  15,  195  (1895).  Arch.  phys.  nat.,  [4], 
1,54(1896). 


20 


PART  FOURTH 

Apparatus  and  Methods  for  Determina- 
tion of  the  Specific  Rotation 

87.  General  Conditions. — In  the    calculation    of    the   specific 
rotation,  the  experimental  determination  of  the  following  data 
is  necessary  : 

1 .  The  measurement  of  the  angle  of  rotation  a  for  a  definite 
light  ray. 

2.  The  measurement  of   the  length  /  of    the  tube  for  the 
liquid,  in  decimeters. 

3.  The  determination  of   the  amount  p   of  active  substance 
in  100  grams  of  solution. 

4.  The  determination  of    the    specific    gravity  d    of    the 
solution. 

5.  The  determination   of   the  amount  c  of  active  substance 
in  loo  cubic  centimeters  of  solution. 

A.  MEASUREMENT  OF  THE  ANGLE  OF  ROTATION 

88.  Ordinary  and  Polarized  Light.— While  in   an  ordinary  light 
ray  the  vibrations  of    the  ether  particles  take   place  in  all 
directions  in  a  plane  perpendicular  to  the  line  of  propagation  of 
the  light,  in  a  ray  of  plane  polarized  light  the  vibrations  of  the 
ether  particles  occur  in  a  single  direction  only.     Such  a  plane 
polarized  ray  is  no  longer  symmetrically  disposed  around  its 
axis.     The  plane  in  which  the  ray  is  polarized  is  known  as  its 
plane  of  polarization. 

The  conversion  of  ordinary  light  into  polarized  light  may 
be  effected,  to  begin  with,  by  reflection,  which  is  accomplished 
by  aid  of  the  apparatus  shown  in  Fig.  22.  If  a  pencil  of  light 
be  allowed  to  strike  the  black  glass  mirror  A  under  an  angle 
of  57°,  the  rays  will  be  reflected  upwards  and  polarized  in  the 


ORDINARY   AND    POLARIZED    LIGHT 


307 


plane  of  incidence.  The  proof  of  this  may  be  given  by  aid  of  the 
second  mirror  B. 
The  reflected  rays 
first  pass  through 
the  empty  vessel 
F,  the  bottom  of 
which  is  formed  of 
a  plate  of  plane 
glass,  and  strike  the 
mirror  B  under 
the  same  incident 
angle  of  57°.  By 
means  of  the  lever 
D  and  the  rack- 
work  at  E,  B  and 
the  paper  screen  C 
may  be  rotated 
around  a  vertical 
axis.  If  the  mirror 
B  has  a  position 
parallel  to  A,  the 
plane  of  incidence 
of  the  polarized  rays 
reaching  B  coin- 
cides with  their 
plane  of  polariza- 
tion, and  in  conse- 
quence there  is  a 
considerable  reflec- 
tion toward  C  where 
a  bright  spot  is 
formed  by  the  pen- 
cil of  light.  On  ro- 
tating the  mirror  B, 
however,  the  inten- 
sity of  the  light  reflected  from  it  gradually  decreases  until 
a  position  is  reached  90°  from  the  original  one,  when  it  is 
found  that  no  more  light  is  reflected  and  the  screen  C 
remains  perfectly  dark.1  The  plane  of  incidence  of  the  rays 

1  All  of  the  light  is  refracted  in  the  glass  and  absorbed  by  the  dark  back  surface. 


Fig.  22. 


308  POLARIZATION    APPARATUS 

is  now  perpendicular  to  the  plane  of  polarization.  On  further 
rotation  of  the  mirror  B,  it  is  found  that  at  180°,  that  is,  in 
the  position  where  the  planes  of  incidence  and  polarization 
again  coincide  at  B,  there  is  a  maximum  and  at  270°  a  minimum 
again  of  reflection. 

89.  Rotation  of  the  Plane  of  Polarization. — Let  the  mirror  B  be 
brought  into  the  position  of  greatest  darkness,   so  that  the 
plane  of  incidence  of  the  rays  polarized  by  the  mirror  A,  and 
reaching  B,  is  vertical  to  the  new  plane  of  polarization.     If 
the  vessel  F  be  now  filled  with  a  cane-sugar  solution,   for 
example,  the  remarkable  phenomenon   is  exhibited  in  which 
the  screen  C  becomes  suddenly  bright  and  remains  so  until  the 
mirror  B  is  rotated  through  a  certain   angle.     Now,  again,  as 
a  matter  of  course,  the  plane  of  incidence  of  the  transmitted 
rays  is  perpendicular  to  their  plane  of  polarization.     It  follows, 
therefore,  that  the  plane  of  polarization  of  the  rays  leflected 
through  the  sugar  solution  has  been  turned  or  twisted  through 
an  angle  equal  to  that  through  which  B  was  turned.     This  angle 
is  known  as  the  angle  of  rotation. 

90.  Iceland  Spar  Prisms. — A  pencil  of  light   may  be  linearly 
polarized  by  double  refraction  in  crystals,  especially  in  Iceland 
spar,  much  more  perfectly  than  by   reflection.     If  a  ray  of 
light  falls  perpendicularly  on  one  of  the  faces  of  a  natural  Ice- 
land  spar   rhombohedron   it   is   broken  up,    on  entering  the 
crystal,  into  two  separate  rays,  unequally  refracted  and  linearly 
polarized  in  planes  perpendicular  to  each  other.     If  we  define 
as   the   optical  axis  of  the  crystal  that  direction  parallel  to 
which  no  double  refraction  and  also  no  polarization  takes  place, 
and  as  the  optical  principal  plane  of  the  incident  ray,  that  plane 
which  includes  the  perpendicular  at  the  point  of  incidence  and 
also  the  optical  axis,  then  the  principal  plane  is  at  the  same 
time  the  plane  of  polarization  of  the  ordinary  refracted  ray, 
while  the  plane  of  polarization  of  the  extraordinary  ray  is  per- 
pendicular to  the  principal  plane.     This  holds  still  accurately 
true  when  the  incident  ray  instead   of  falling  vertically  upon 
the  surface  of  the  crystal  strikes  it  at  any  angle,  as  long  as  the 
incident  plane  is  at  the  same   time  a  principal  plane  of  the 
crystal.     In  the  practical  applications  of  these  rays  in  polar- 


ICELAND    SPAR    PRISMS 


309 


ization  instruments  it  is  better  to  permit  only  one  to  emerge, 
in  the  direction  of  the  incident  light,  while  the  other  is  elimin- 
ated. This  may  be  accomplished  in  various  ways,  most  per- 
fectly on  converting  the  Iceland  spar  into  a  Nicol  prism. 
The  polarization  prisms,1  described  at  length  below,  are  used 
in  the  modern  forms  of  polarization  inslruments  for  scientific 
as  well  as  for  technical  purposes. 

i.  NicoVs  Prism. — This,  which  is  the  most  widely  known 
type,  is  made  in  the  following  manner  :  A  rhombohedron, 
abed  (Fig.  23),  the  length  of  which  is  fully 
three  times  the  wridth,  is  cut  from  a  clear  crystal 
of  Iceland  spar  ;  the  end  surfaces,  which  make 
originally  angles  of  7 1  °  with  the  side  edges,  are 
polished  off  so  that  these  angles,  at  a  and  c,  be- 
come 68°,  and  then  the  prism  is  sawed  through 
in  the  direction  b' ,  d' .  After  the  angles  a  V  d' 
and  c  d'  b'  are  ground  down  to  90°  and  the  sawed 
surfaces  polished  they  are  cemented  together  again 
in  the  original  position  by  means  of  Canada  bal- 
sam. Finally  the  side  surfaces  are  blackened  and 
the  finished  nicol  is  fastened  into  a  brass  frame 
by  aid  of  cork.  The  optical  principal  plane  of 
the  prism  for  all  rays  falling  on  the  ends  is  the  plane  vertical 
to  the  end  surfaces  and  passing  through  the  optical  axis. 

In  illustration,  if  a  ray  of  light  whose  plane  of  incidence 
contains  the  optical  axis  falls  upon  one  of  the  end  surfaces, 
it  is  divided  on  entering  into  two  rays  polarized  perpendicularly 
to  each  other.  In  case  the  entering  ray  makes  but  a  small 
angle  with  the  axis  of  length  of  the  prism,  the  ordinary  com- 
ponent suffers  total  reflection  on  the  cement  surface,  is  thrown 
to  the  dark  side  surface  and  is  here  largely  absorbed,  while 
the  extraordinary  component  passes  through  the  cement  and 
emerges  alone  from  the  second  end  surface  in  a  direction 
parallel  to  that  of  entrance.  The  plane  of  polarization  of  this 
emerging  ray  is  vertical  to  the  principal  plane. 

If  a  small  flame  at  some  distance  is  observed  through  the 
nicol,  under  such  condition  that  the  entering  rays  make  but  a 

1  Feussner :  "  Ueber  die  Prismen  zur  Polarisation  des  lyichtes,"  Ztschr.  f.  In- 
strum.,  4,41  ( 1884).  Grosse:  "Ueber  Polarisationsprismen,"  Ztschr.  f.  Instrum.,  10,445 
(1890).  Halle:  "Ueber  Herstellung  Nicol'scher  Prismen,"  V.  d.  D.  Ges.  f.  Mech.  u.  Opt., 
143  (1896). 


Fig.  23. 


3io 


POLARIZATION    APPARATUS 


small  angle  with  the  axis  of  length  of  the  prism,  the  eye  perceives 
uniform  illumination  within  a  certain  limited  field,  and  the  planes 
of  polarization  of  the  individual  linearly  polarized  rays  coming 
through  the  prism  deviate  very  little  from  each  other,  that  is, 
within  certain  limits,  they  are  all  polarized  perpendicularly  to 
the  principal  section  of  the  nicol.  It  may  then  be  briefly  said 
(although  not  with  absolute  accuracy)  that  when  a  pencil  of 
light  passes  through  a  nicol,  the  emerging  light  is  linearly 
polarized,  and  in  a  direction  vertical  to  the  principal  section.1 
The  plane  of  polarization  of  the  light  emerging  from  a 
nicol  can  be  found  most  simply,  empirically,  by  aid  of  a 
revolving  glass  mirror.  The  light  from  the  prism  is  allowed 
to  strike  the  mirror  under  an  incident  angle  of  57°,  and  the 
glass  is  then  rotated  around  the  rays  as  an  axis  until  all 
reflected  light  disappears.  According  to  §  88  the  plane  of 
polarization  of  the  nicol  is  now  vertical  to  the  incident  plane 
of  the  rays  on  the  mirror. 

2.  Hartnack-Prazmowski  Prism.  —  From  the  natural  crystal, 

(b  abed  (Fig.  24),  the  prism  a'  b'  cf  d'  is  cut 
out  and  sawed  in  the  direction  a'  c'.  After 
the  surfaces  a'  b'  and  c'  d'  and  the  sawed 
surfaces  a'  cf  are  ground  and  polished  the 
latter  are  cemented  together.  The  entering 
angle  b'  a'  c'  must  vary  according  as  Canada 
balsam,  linseed  oil  or  other  transparent 
cement  is  employed.  Although  the  loss  of 
material  on  cutting  the  crystal  is  greater 
than  in  the  Nicol  prism,  the  Hartnack 
prism  possesses,  notwithstanding  its  shorter 
length,  a  much  greater  field  of  view.  Be- 
sides this,  it  has  the  advantage  of  presenting 
straight  end  surfaces.  In  the  prism,  as  de- 
scribed by  Hartnack,  the  optical  axis  stands 
vertical  to  the  plane  of  the  section  a'  c'  ;  the 
optical  principal  section  is,  therefore,  a  plane 
through  the  axis  of  length  and  vertical  to  the  cut  surface. 

3.  Prism  of  Clan  [-Thompson].'2— A  much  greater  loss  of 

1  For  further  details  see  I^ippich  :  "  Ueber  polaristrobometrische  Methoden,  Wien. 
Sitzungsber.  II,  85,  268  (1882). 

2  Lippich  has  constructed  a  similar  prism.     Wien,  Sit/.miK.sber.  II,  9i,  1079.  (1885). 
The  r.lan  prism  with  air  layer  is  not  to  be  confounded  with  the  above. 


Fig.  24. 


POLARIZER    AND    ANALYZER 


Fig-  25. 


material  than  in  the  last  prism  is  suffered  in  that  of  Glan.  On 
a  symmetrical  rhombohedral  crystal,  two  surfaces  are  ground 
down  parallel  to  each  other  and  perpendicular  to  the  optical 
axisof  the  crystal  ABC  (Fig.  25); 
vertically  to  these  surfaces  the  prism 
a  b  c  d  is  then  cut  out  and  sawed 
through  in  the  direction  bd.  After 
the  surfaces  a  b  and  c  d,  and  the  cut 
faces  b  d  are  ground  and  polished, 
the  two  halves  are  cemented  to- 
gether. The  angle  a  b  d  depends, 
as  before,  on  the  kind  of  cement  C 
which  is  employed. 

The  Glan  prism  surpasses  the 
others  described  in  having  an  es- 
sentially larger  opening  with  corresponding  length  ;  the  field 
of  view  is  also  normal  to  and  symmetrical  with  the  axis  of 
length  of  the  prism.  This  prism  may  therefore  be  described 
as  scientifically  the  most  perfect  form,  and  for  this  reason  it 
has  come  into  use  as  the  polarizing  prism  in  all  good  instru- 
ments. As  the  optical  axis  of  the  prism  is  adjusted  parallel  to 
the  refractive  edges  b  and  d  of  the  piece  of  spar,  it  follows  that 
the  optical  principal  section  is  a  plane  through  the  axis  of 
length  and  vertical  to  the  edge  a  b. 

91.  Polarizer  and  Analyzer. — If  ordinary  light  from  any  source 
is  passed  through  a  nicol  the  emerging  light,  as  explained  in 
the  last  paragraph,  is  linearly  polarized  per- 
pendicularly to  the  principal  section.    Such  a 
linearly  polarized  ray  may  be  decomposed,  like 
a  force,    into  two   linearly   polarized  compo- 
nents, vertical  to  each  other  as  regards  their 
planes  of  polarization.     If  then  linearly  polar- 
ized light,  the  plane  of  polarization  and  ampli- 
tude of  which  is  A  B  (Fig.  26),  falls  on  a  new 
Nicol,   the    principal    section  C  D    of  which 
makes  an  angle  ex  with  A  B,  this  light  may 
be  broken  up  into  two  components,  A  E  =  A  B 
cos  a  and  A  F  =  A  B  sin  a.     Only    the    latter    component, 
which    is   perpendicular   to   the   principal   section,  will   pass 


Fig.  26. 


312  POLARIZATION    APPARATUS 

through,  while  the  component  A  E,  which  is  polarized  in 
the  principal  section,  is  completely  extinguished  by  the  nicol. 
Of  a  linearly  polarized  light  ray  only  that  component  can  pass 
a  Nicol  prism  which  is  perpendicular  to  the  principal  section, 
and  this  component  is  the  smaller  the  smaller  the  angle  which 
the  plane  of  polarization  of  the  entering  ray  makes  with  the 
principal  section  of  the  nicol.  If  now  the  nicol  is  rotated  all 
light  passes  when  C  D  is  brought  perpendicular  to  A  B  ;  on 
further  turning,  the  light  passing  becomes  gradually  weaker, 
and  after  reaching  90°  (CD  parallel  with  A  B)  complete 
darkness  follows.  On  still  further  turning,  the  light  reappears 
and  reaches  a  maximum  of  brightness  at  180°,  and  so  on. 

Let  the  following  conditions  be  considered  :  We  place  two 
Nicol  prisms  between  the  eye  and  a  small  luminous  surface  at 
some  distance,  and  one  before  the  other  in  such  position  that 
their  principal  sections  are  parallel  with  the  line  of  vision. 
The  nicol  nearest  the  light  may  be  in  fixed  position  while  the 
one  next  the  eye  may  be  rotated  around  its  axis  of  length. 
The  first  one  is  called  the  polarizer  and  the  other  the  analyzer. 
The  light  reaching  the  polarizer  from  the  luminous  surface  is, 
after  passage,  linearly  polarized  vertically  to  the  principal  sec- 
tion. This  next  reaches  the  analyzer.  If  this  is  at  first 
turned  so  that  its  principal  section  is  parallel  with  that  of  the 
polarizer,  the  already  polarized  light  suffers  no  further  change 
in  passing  through  the  analyzer,  and  the  eye  perceives  the 
field  of  view  brightly  illuminated.  This  is  also  the  case  when 
the  analyzer  is  turned  through  180°,  which  brings  the  prin- 
cipal sections  into  parallel  position  again.  If,  next,  the 
analyzer  be  so  placed  that  its  principal  section  crosses  that  of 
the  polarizer  at  right  angles  the  polarized  light  will  be  com- 
pletely shut  off,  because  now  its  plane  of  polarization  and  the 
principal  section  of  the  analyzer  coincide.  The  rays  entering 
the  analyzer  behave  as  ordinary  polarized  rays  until  the  cement 
layer  is  reached  and  here  they  are  thrown  off  by  reflection. 
No  light  can,  therefore,  pass  the  analyzer  and  the  field  of  view 
remains  dark.  The  same  is  true  after  rotating  180°.  In  all 
other  cases  in  which  the  principal  sections  of  the  two  nicols 
are  neither  parallel  nor  vertical,  a  part  of  the  light  entering  the 
analyzer  will  be  allowed  to  pass,  and  always  that  component 


POLARIZATION    APPARATUS 


313 


which  is  polarized  perpendicularly  to  the  principal  section  of 
the  analyzer. 

92.  Polarization  Apparatus. — The  apparatus  shown  in  Fig.  27 
may  be  used  for  the  observation  of  these  phenomena.  The 
horizontal  bar  d,  supported  on, 
a  stand,  carries  at  one  end  the 
polarizing  Nicol,  a,  in  fixed  bjj 
position,  and  at  the  other  the 
analyzer  b,  which  may  be 
turned  with  its  receptacle,  by 
means  of  the  lever  c,  around 
its  axis.  A  single  or  double 
pointer  is  turned  with  it  over 
the  graduated  circle  fastened 
also  to  the  bar,  d.  Between 
the  Nicols  the  tube,  f,  may  be 
placed,  the  ends  of  which  are 
closed  by  glass  plates. 

The  polarizer  is  first  turned 
toward  a  source  of  light,  which 
for  the  sake  of  greater  sim- 
plicity in  the  phenomenon 

should  be  monochromatic,  such  as  given,  for  example,  by  a  Bun- 
sen  burner  and  sodium  carbonate  bead.  At  first  the  tube  re- 
mains empty.  On  looking  through  the  analyzer  and  rotating  it, 
a  position  is  easily  found  in  which  the  field  appears  at  its  greatest 
darkness.  Assuming  that  the  pointer  is  now  at  o°  on  the  circle, 
from  what  was  said  above  it  will  appear  that  the  second  position 
of  darkness  will  be  at  180°,  and  the  two  brightest  positions  at 
90°  and  270°.  For  the  observations,  the  darker  positions  are 
more  suitable  than  the  light  ones,  because  with  the  former  a 
small  motion  of  the  nicol  makes  a  very  perceptible  change. 

The  position  of  the  analyzer  at  which  the  field  has  the 
greatest  darkness,  is  called  the  zero  point  of  the  apparatus.  In 
this  position  the  plane  of  polarization  of  the  light  coming  from 
the  polarizer  coincides  with  the  principal  section  of  the  analyzer. 
If  now  the  tube  f  be  filled  with  a  cane-sugar  solution  and 
placed  in  the  apparatus,  the  plane  of  polarization  of  the  light 
coming  from  the  polarizer  will  undergo  rotation  through  a 


314  POLARIZATION    APPARATUS 

certain  angle,  ar,  by  action  of  the  sugar  solution  as  explained 
above.  In  consequence  of  this,  the  field  of  view  becomes 
bright.  Darkness  will  come  again  when  the  principal  section 
of  the  analyzer  is  brought  into  parallel  position  /with  the 
rotated  plane  of  polarization  ;  that  is,  when  the  analyzer,  also, 
is  turned  through  the  angle  a.  This  angle  a  may  be  read 
off  on  the  graduated  circle  and  is  equal  to  the  angle  of  rotation 
of  the  sugar  solution.  If  after  putting  an  optically  active 
substance  in  the  tube,  it  is  necessary  to  turn  the  analyzer  from  o 
in  the  direction  of  the  clock-hand  motion  to  reach  the  point 
again  where  the  light  disappears,  the  substance  is  said  to  be 
right  rotating ;  if  the  analyzer  is  turned  in  the  opposite 
direction  to  reach  the  same  end,  the  substance  is  left-rotating. 

93.  Determination  of  the  Direction  and  Angle  of  Rotation.— 
With  exception  of  the  Wild  polaristrobometer,  which  has 
four  zero  points,  all  polarization  instruments  have  two  zero 
points  1 80°  apart.  We  assume,  first,  that  we  have  to  do  with 
one  of  the  latter  forms.  By  the  aid  of  such  apparatus  we  have 
to  determine  the  direction  of  rotation,  and  the  amount  of  rota- 
tion of  an  active  substance.  After  adjusting  the  apparatus  to 
the  zero  point  and  putting  the  active  substance  in  position, 
the  analyzer  must  be  turned  say,  through  -f  a°  (a  certainly 
less  than  180°),  that  is,  in  the  clock-hand  direction,  to  darken 
the  field  again.  The  angle  a  read  off  is  not  yet  necessarily  the 
angle  of  rotation  ;  as  regards  whole  multiples  of  ±  180°  it  is 
yet  quite  undetermined.  It  can  only  be  said  that  the  angle 
of  rotation  of  the  substance  is  equal  to  ot°  ±  n  180°,  where  n  is 
either  o  or  a  whole  number  to  be  determined.  In  the  case  of  a 
solid  substance,  if  the  thickness  of  the  layer  is  not  above  a  few 
millimeters,  or  in  the  case  of  a  liquid  if  the  tube  length  is  not 
above  two  decimeters,  then,  unless  the  substance  is  one  possess- 
ing unusually  great  activity,  the  angle  of  rotation  will  be  less 
than  1 80°,  so  that  the  choice  will  lie  between  -f-  ot°  and 
-f  a°  -  1 80°.  In  order  to  decide  between  these  two  angles 
the  same  substance  must  be  examined  in  a  layer  of  just  one-half 
the  thickness,  or,  in  the  case  of  solutions,  one  of  just  half  the 
concentration,  with  the  same  tube  length,  may  be  employed ; 
now  the  angle  of  rotation  will  be  half  as  great  as  before.  Sup- 
pose the  angle  is  now  -f  ft,  a  simple  consideration  will  show 


DIRECTION  AND  ANGLE  OF  ROTATION  315 

ot 

this  :  If  @  =  —  the  substance  is  right  rotating  with  an  angle 

of  a  for  the  full  thickness  of  layer.     If  ft  =  90°  +  -  then  the 

substance  is  left  rotating  with  an  angle  of  rotation  equal  to 
a°  —  180°  for  the  full  thickness  of  layer. 

The  direction  of  rotation  of  a  liquid  may  be  very  conve- 
niently found  by  filling  it  into  the  control  observation  tube, 
with  variable  length,  of  Schmidt  and  Haensch,  to  be  later 
described.  After  putting  the  tube  in  place  the  analyzer  is 
moved  to  the  position  of  darkness  ;  the  tube  is  then  length- 
ened a  little,  which  produces  a  brightening  of  the  field.  If  it 
is  now  necessary  to  turn  the  analyzer  a  few  degrees  in  the 
clock  motion  direction  to  secure  darkness  again,  the  liquid  is 
right  rotating ;  but,  on  the  other  hand,  if  the  analyzer  must 
be  turned  in  the  opposite  direction  the  liquid  is  left-rotating. 

The  determination  of  the  direction  and  amount  of  rotation 
by  aid  of  the  Wild  instrument  is  more  complicated,  -because 
this  possesses  four  zero  points  90°  apart.  Under  the  assump- 
tion that  the  angle  of  rotation  is  less  than  ±90°,  the  direction 
and  number  of  degrees  of  rotation  may  be  found  by  a  plan 
similar  to  that  just  outlined,  by  working  first  with  a  layer  of 
full  length  and  then  with  one  of  half  the  length.  But  if 
angles  up  to  ±  180°  are  possible  then  a  third  length  of  layer 
of  substance  must  be  taken  which  is  one-fourth  the  first 
length.  Here  also  the  application  of  the  Schmidt  and 
Haensch  control  observation  tube  would  be  advantageous,  the 
length  being  first  contracted  to  one-half  and  then  to  one- 
fourth.  The  position  of  the  Nicol  is  then  always  observed  in 
the  first  quadrant,  between  o°  and  90°,  and  the  graduation  on 
the  circle  follows  in  this  manner,  that  in  the  case  of  a  small 
right-rotation  of  the  plane  of  polarization,  with  observations 
in  the  first  quadrant,  small  numbers  close  to  the  o  are  read  off. 
The  correctness  of  the  following  can  then  be  easily  demon- 
strated ;  if  the  reading  with  full  thickness  of  layer  is  «°,  and 
if  further,  with  one-fourth  this  thickness,  it  is 

=  —i  then  substance  is  right  rotating  with  the  angle  o°, 

4 

=  22.5  +  —i   then  substance  is  right  rotating  with  the  angle     90°  -{-  a°, 


316  POLARIZATION  APPARATUS 

—  45     H ,    then  substance  is  left  rotating  with  the  angle      180°  —  a°, 

4 

=  67.5  H ,   then  substance  is  left  rotating  with  the  angle        90°  —  a°; 

4 

Here  the  angles  a,  90°  -f  «,  180°  -  of,  90°  -  a  refer  to 
the  full  thickness  of  layer. 

a.  Polarization  Instruments 

94.  Polarization  Apparatus  and  Saccharimeters. — For  the  exact 
measurement  of  the  angle  of  rotation  different   instruments 
have  been  constructed,   which,   according  to  their  uses,   are 
divided  into  two  classes.     These  are  : 

1.  The  so-called  Polariscopes  or  Polaristrobometers . — These 
are   used   for   scientific   purposes  in  the  investigation  of   all 
active   substances.     They   have   a    circular    graduation    and 
require  homogeneous  light. 

2.  The  Saccharimeters.  — These  are  specially  constructed  for 
the  determination  of  the  strength  of  sugar  solutions.     In  place 
of  the  circular  graduation,  they  have  a  quartz  wedge  compen- 
sation with  linear  scale  and  employ  white  light.     They  are 
used  chiefly  in  the  sugar  industry. 

95.  Construction  of  the  Polariscopes. — Before  taking  up  the  descrip- 
tion of  the  special  forms  of  instruments,   a  short  discussion  of 
the  requirements  in  a  good  polariscope  will  be  given,   and  also 
an  explanation  of  the  path  of  the  light  rays  through  the  appa- 
ratus. !     The  following  considerations  obtain  for  all  polariscopes 
and  Saccharimeters,  with  the  exception  of  the  Wild  instrument, 
which,  in  principle,  is  different  from  all  other  forms  of  appa- 
ratus. 

Those  optical  parts  which  all  polarization  instruments  have, 
in  common,  are  shown  in  Fig.  28.  The  light  from  the  lumi- 
nous body  A  passes  through  the  lens  B  into  the  instrument  and 
is  linearly  polarized  by  the  polarizer  C.  Immediately  in  front 
of  this  is  found  the  round  polarizer  diaphragm  D,  which  is 
focused  on.  Then  follow  the  round  analyzer  diaphragm  E, 
the  analyzer  F,  and  a  reading  telescope.  In  the  figure  an 

i  See,  also  Uppich:  Wien.  Sitzungsber.,  II,  85,  268  (1882)  ;  91,  1059  (1885).  These 
considerations  on  the  construction  of  apparatus  and  the  path  of  the  light  rays  should 
be  carefully  followed,  in  all  more  exact  work,  if  otic  wishes  to  be  certain  of  excluding 
bad  systematic  errors  in  the  results. 


CONSTRUCTION   OF   THE   POLARISCOPES 


317 


ordinary  astronomical  telescope  is  shown  with  the 
objective  G,  the  ocular  H,  and  the  diaphragm  J, 
in  front  of  which  the  eye  of  the  observer  is  placed. 
At  the  outset,  the  parts  from  B  to  J  must  be  ac- 
curately adjusted  with  reference  to  the  axis  of 
the  instrument.  Inasmuch,  as  wre  shall  presently 
see,  as  all  light  going  through  the  instrument  is 
limited  by  the  diaphragms  D  and  E,  at  any  rate 
in  the  forms  as  now  commonly  constructed,  and 
as  all  bodies  to  be  investigated  with  reference  to 
their  rotating  power  are  placed  between  D  and 
E  we  shall  understand  as  the  axis  of  the  apparatus 
from  now  on,  the  line  which  unites  the  centers 
of  the  diaphragms  D  and  E.  All  other  optical 
parts  of  the  instrument  must  be  exactly  centered 
this  line.  Although  the  adjustment  of  the 


on 


illuminating  lens  B  need  be  only  approximately 
correct,  the  polarizer  C  must  be  so  centered  that 
its  optical  principal  section  is  exactly  parallel  to 
this  axis  of  the  instrument.  As  regards  the  size 
of  the  diaphragms  D  and  E,  these  must  be  corre- 
spondingly smaller  than  the  cross  dimensions  of 
the  prisms  C  and  F,  so  that  a  sufficiently  broad 
border  of  about  two  millimeters  in  diameter 
around  the  edges  of  the  prisms  should  be  ob- 
scured. 33 

While  in  the  case  of  the  saccharimeters  all  the 
optical  parts  are  fixed  with  exception  of  the  ocu- 
lar H  J,  which  is  movable  in  the  direction  of  the 
axis,  in  the  polariscopes  the  parts  E  to  J  may  be 
rotated  around  a  common  axis.  This  axis  of  rota- 
tion, which  at  most  should  not  be  inclined  more 
than  a  few  minutes,  must  coincide  exactly  with 
the  axis  of  the  apparatus.  This  may  be  easily 
secured  in  the  smaller  forms  of  apparatus,  which, 
like  the  saccharimeters,  can  be  worked  out  in  the 
lathe,  but  is  realized  with  greater  difficulty  in  the 
larger  instruments,  which  are  composed  of  the 
distinct  parts  B  to  D  and  E  to  J.  It  may  hap- 


318  POLARIZATION   APPARATUS 

pen  here,  that,  in  instruments  most  excellent  in  all  other 
respects,  the  inclination  of  the  axis  of  rotation  with  refer- 
ence to  the  axis  of  the  apparatus  may  amount  to  as  much  as 
ten  minutes  or  even  more.  In  order  to  avoid  such  an  error 
the  diaphragm  D  must  be  attached  after  the  other  parts  of  the 
apparatus  are  fastened  to  the  support,  and  then,  if  necessary, 
eccentrically  with  reference  to  the  thread.  The  optical  prin- 
cipal section  of  the  analyzer  F  must  be  exactly  parallel  to  the 
axis  of  the  apparatus  and  the  axis  of  rotation,  while  the 
requirement  that  the  axis  of  rotation  must  be  at  the  same  time 
the  optical  axis  of  the  telescope  G  H  J,  is  one  which  can 
always  be  met  satisfactorily. 

But,  above  all,  care  must  be  taken  to  have  the  adjustment 
of  the  prisms  C  and  F,  with  reference  to  each  other,  a  fixed 
and  unchangeable  one,  as  otherwise  constant  variations  in  the 
zero  point  would  result.  With  the  saccharimeters,  therefore, 
the  prism  must  be  fixed  once  for  all,  and  in  the  polariscopes 
the  optical  principal  section  of  the  rotating  analyzer  must 
remain  always  parallel  to  the  axis  of  the  instrument.  We 
have  the  following  two  criteria  by  which  to  determine  whether 
or  not  the  prisms  in  the  polariscope  are  properly  adjusted  and 
free  from  errors.  First,  the  two  zero  points  of  the  apparatus 
must  be  exactly  180°  apart  ;  second,  if  a  large  angle,  say  90° ,  is 
measured,  the  two  final  observation  readings  180°  apart  must 
give  exactly  the  same  value  for  the  angle  of  rotation. 

While  with  the  smaller  polariscopes  the  graduated  circle 
generally  remains  at  rest  with  the  rotation  of  the  analyzer, 
and  the  verniers  only  move,  in  the  larger  instruments  the 
graduated  circle  rotates  with  the  analyzer.  In  order  to  elimi- 
nate the  unavoidable  errors  of  graduation  in  the  circle,  the 
analyzer  is  furnished  with  a  setting  which  may  be  rotated 
independently,  or  the  shell  to  which  the  verniers  are  attached 
may  be  turned  through  360°,  which  is  easily  done.  In  this 
way  the  zero  point  of  the  apparatus  may  be  brought  to  correspond 
to  any  part  of  the  circle,  and  the  rotation,  therefore,  measured 
with  different  parts  of  the  graduation .  In  order  to  eliminate  the 
eccentricity  of  the  circle,  that  is,  the  error,  which  is  due  to 
the  fact  that  the  axis  of  rotation  does  not  pass  exactly  through 
the  center  of  the  disk,  two  observation  verniers,  180°  apart,  are 


PATH    OF   THE    RAYS  319 

always  attached.  Both  of  these  must  be  read  each  time  and 
the  mean  of  the  angles,  as  given  by  each  vernier,  taken  ;  of 
course,  with  the  double  reading  the  error  of  observation,  also, 
is  reduced.  Besides,  the  plane  of  the  graduated  circle  must  be 
vertical  to  the  axis  of  rotation,  otherwise,  different  values  for 
the  same  angle  of  rotation  would  be  found  on  different  parts 
of  the  graduation.  But  such  an  error  is  not  greatly  to  be 
feared,  as  it  is  not  a  difficult  matter  for  the  instrument-maker 
to  fulfil  this  requirement  in  a  satisfactory  manner. 

96.  Path  of  the  Rays  in  the  Polariscope. — If  one  wishes  to  secure, 
in  reality,  the  remarkable  accuracy  which  may  be  reached  in 
the  best  forms  of  polariscopes,  it  is,  above  all,  necessary  to  pro- 
vide for  a  perfectly  correct  course  of  the  rays  through  the  instru- 
ment to  the  eye  of  the  observer.  In  all  accurate  polariscopes  or 
saccharimeters,  the  observer  focuses  on  a  field  which  is  made  up 
of  two  or  more  separate  fields,  the  illuminations  of  which  are 
compared  with  each  other.  If  full  advantage  is  taken  of  the  deli- 
cacy of  this  method  of  reading,  the  brightness  of  each  separate 
field  must  be  perfectly  uniform,  and  second,  with  the  apparatus 
at  rest,  the  degree  of  illumination  on  the  several  fields  must 
remain  absolutely  constant,  or,  expressed  differently,  the  dis- 
tribution of  the  illumination  in  the  whole  field  of  view  must  re- 
main always  uniform.  Both  conditions  could  easily  be  reached 
if  the  source  of  light  were  uniform  in  intensity  throughout. 
This  is,  however,  never  absolutely  the  case,  and  it  must  then 
be  determined  how  the  rays  may  be  passed  through  the  apparatus 
in  order  that  the  two  requirements  mentioned  may  be  satisfied, 
notwithstanding  changes  and  irregularities  in  the  distribution  of 
the  luminosity  of  the  source  of  light  itself.  It  must  be  assumed, 
however,  that  every  point  in  the  source  of  light  illuminates 
equally  in  all  directions.  This  condition  will  always  obtain, 
if  the  small  surface  of  the  illuminating  lens,  and  only  such  can 
be  considered  here,  is  kept  at  a  relatively  great  distance  from 
the  source  of  light,  and  this  will  be  assumed  in  what  is  to  come. 
In  order  to  simplify  the  following  discussion  let  us  imagine 
first  the  two  polarization  prisms  C  and  F  of  Fig.  28  removed 
and  the  two  diphragms  D  and  E  brought  close  to  the  two 
lenses  B  and  G,  so  that  we  have  essentially  only  the  luminous 


320 


POLARIZATION   APPARATUS 


surface  A  (Fig.  29),  the  illumina- 
ting lens  B,  which  is  now  focused 
on,  and  the  telescope  G  H  J  left. 
We  shall  consider  first  the  path 
of  the  rays  in  the  case  in  which 
\hzpolarization  prisms  are  placed 
in  parallel  light  rays.     In  order 
to  realize  this  condition  we  must 
choose  an  illumination  lens  of  long 
focus  and  place  the  luminous  body 
in  its  focal  plane.  A  is,  therefore, 
in  the  focal  plane  of  the  lens  B. 
Let  L   M  represent   the  axis  of 
the   apparatus.      The  degree  of 
brightness  under  which  an  ele- 
ment of  surface  at  the  point  N  of 
the  illuminating  lens  is  seen,  de- 
pends on  the  cone  of  rays  a  N  b, 
supposing  the  luminous  surface 
at  A  large  enough  to  begin  with, 
and  that  all  the  rays  in  the  cone 
a  N  b  actually  pass  through  the 
reading  telescope  and  reach  the 
eye  of  the  observer.    Since  all  the 
rays  in  the  cone  a  N  b  were,  be- 
fore passing  the  leas  B,  in  the 
cone  aj  N  b, ,  therefore  the  bright- 
ness at  N  is  proportional  to  the 
amount  of  light  which  is  sent  out 
from  the  part  a,  b,  of  the  lumi- 
nous surface.      If  we  consider  a 
point  at  O,  near  the  edge  of  B, 
its  brightness  is  determined  by 
the  cone  a  O  b.     Remembering 
now   that  A  is  situated  in   the 
focal  plane  of  B  it  follows  that 
corresponding  to  the  cone  a  O  b 
we  have,  before  passing  the  lens, 
the  cone  a,  O  b,,   in   which,  for 


PATH    OF   THE    RAYS    IN   THE    POLARISCOPE 


321 


example,   a  O  is  parallel  with  a2  N.     The  brightness    at    O 
is   proportional,   therefore,    to   the   amount   of  light   emitted 
bt   L  ai  from  a.2  b.2  of  the  luminous  body.     In 

the  same  manner  the  brightness  at  P, 
a  point  symmetrical  with  O,  is  propor- 
tional to  the  light  emitted  from  the  part 
a3  b3  of  the  luminous  body.  We  see, 
therefore,  that  for  every  point  of  B,  the 
corresponding  part  an  bn  embraces  a 
different  portion  of  the  luminous  body. 
It  follows,  therefore,  that  unless  the 
area  b.2  a3  of  the  luminous  body  is  uni- 
>]  form  in  brightness,  the  lens  B  cannot 

appear  uniformly  bright,  and  further 
that  the  distribution  of  the  illumina- 
tion at  B,  on  account  of  changes  in  the 
luminous  body,  may  be  different  at  dif- 
ferent times  ;  but  if  the  luminous  sur- 
face is  narrowed  down  to  the  portion 
b3a2,  the  luminosity  in  every  part  of 
B  is  then  proportional  to  the  light 
emitted  from  b3  a2.  Now,  whatever 
the  distribution  of  the  light  may  be  in 
the  part  b.<  a2,  the  lens  B  will  appear 
uniformly  bright,  as  in  principle  it  is 
required  to  be. 

If  the  diameter  of  the  diaphragm  B 
is  represented  by  dlt  and  that  of  the 
diaphragm  G  by  d2,  the  distance  be- 
tween the  two  diaphragms  by  <rand  the 
focal  distance  of  the  lens  B  by  /,  a 
simple  examination  shows  that  the  di- 
ameter e,  of  the  diaphragm  in  front  of 
the  light,  that  is  b3  a2,  is  determined 
M  by  the  expression,  e=/(d.2  —d^  -+-  c. 

Fi&-  3°-  If  then,  the  lens  B  is  to  appear  uni- 

formly bright,  the  objective  G  must  be  so  chosen  as  to  be  larger 
than  the  field  of  view  on  B,  and  care  must  also  be  taken  to 
shut  out  so  much  of  the  light  by  means  of  a  diaphragm  that 

21 


322  POLARIZATION  APPARATUS 

the  luminous  disk   remaining  is  smaller  than/(</,  —  d^]  -t- c. 

Essentially  simpler  and  more  favorable  are  the  conditions 
when  the  polarization  prisms  are  placed  in  convergent  light. 
In  Fig  30  let  A  again  represent  the  luminous  surface,  B  the 
illumination  lens  to  be  focused  on,  and  G  H  J  the  reading 
telescope.  We  give  the  light  A  such  a  position  that  its  image 
is  produced  through  B  at  G,  which  may  always  be  easily  done 
by  properly  choosing  B.  Then  the  brightness  of  the  point  N on 
the  illumination  lens  is  determined  by  the  cone  aNb,  equiva- 
lent toajNbr  The  brightness  of  N  is  thus  proportional  to 
the  amount  of  light  emitted  by  al  br  If  we  consider  another 
jx)int  O  on  the  lens,  its  illumination  will  be  determined  by 
a  Ob.  This  corresponds  to  aj  O  bt  as  a  b  is  the  image  of  ajbr 
The  brightness  at  O  is,  therefore,  also  proportional  to  the  light 
emitted  by  ajb,.  Each  point  on  B  consequently  receives  its 
light  from  the  part  a,  b,  of  the  luminous  surface,  so  that  the 
lens  B  appears  uniformly  illuminated,  however  the  distribu- 
tion of  the  luminosity  in  the  source  of  light  may  be  changed. 
If  any  part  of  ajbt  be  shut  off  by  a  screen,  the  total  illumi- 
nation of  the  field  of  view,  B,  will  be  decreased,  but  the 
uniformity  of  the  light  will  remain  undisturbed.  It  may  be 
looked  upon  then  as  an  important  rule  which  should  always  be 
followed,  that  the  source  of  light  should  be  given  such  a 
position  that  its  image  may  be  thrown  upon  the  telescope 
objective  by  the  illumination  lens  B. 

In  the  forms  of  apparatus  now  common,  the  entering  light 
rays  are  not  limited  by  the  diaphragms  of  the  illumination 
and  telescope  objective  lenses,  but  by  the  polarizer  and 
analyzer  diaphragms,  and  it  is  the  polarizer  diaphragm  which 
is  focused  on,  and  which  therefore  must  appear  uniformly 
illuminated.  This  will  always  be  the  case,  as  may  now  be 
readily  understood,  if  the  source  of  light  is  given  such  a  position 
that  its  image,  through  the  illumination  lens,  is  thrown  on  the 
analyzer  diaphragm?  it  being  understood,  of  course,  that  none 
of  the  ray  bundles  appearing  between  the  polarizer  and  analyzer 
diaphragms,  if  followed  back  to  the  light  or  forward  to  the  eye, 

1  To  determine  this,  hold  a  piece  of  white  paper  over  the  analy/rr  diaphragm  and 
a  pointed  wire  just  in  front  of  the  source  of  light;  then  the  light,  with  the  wire,  is 
given  such  a  position  that  a  sharp  image  of  the  point  is  produced  on  the  paper  at  the 
diaphragm  opening 


PATH  OF  THE  RAYS  IN  THE  POLARISCOPE  323 

suffer  a  partial  interruption.  As  may  be  shown  easily,  the 
diaphragm  /  of  the  illumination  lens  must  be  taken  greater 
than  (gi  -\-gk-\-  hk)  -=-  /,  and  on  the  other  hand,  the 
diaphragm  n  of  the  telescope  objective  must  be  larger  than 
(hi  -f  hm  -f-  gm)  -i-  z,  where  g  represents  the  diameter  of  the 
polarizer  diaphragm,  h  the  diameter  of  the  analyzer  diaphragm, 
i  the  distance  between  polarizer  and  analyzer  diaphragms,  k 
the  distance  between  polarizer  diaphragm  and  illumination 
lens,  and  /«,  finally,  the  distance  between  the  analyzer 
diaphragm  and  telescope  objective.  As  may  be  seen,  the 
polarizer  and  analyzer  diaphragms  may  have  the  same  or  dif- 
ferent openings  ;  but,  it  is  preferable  not  to  make  the  polarizer 
diaphragm  too  small,  as  the  sensitiveness  of  the  readings 
becomes  less  with  smaller  field  of  view,  and  to  take  the 
analyzer  diaphragm  as  large  as  possible,  as  the  brightness  of 
the  field  increases  with  its  size.  As  regards  the  focal  length 
of  the  illumination  lens  it  is  desirable  to  produce  a  full-sized 
image  of  the  source  of  light  with  it,  and  this  focal  length 
should  be,  therefore,  equal  to  half  the  distance  between  it  and 
the  analyzer  diaphragm,  with  the  light  placed  at  a  distance 
from  the  illumination  lens  equal  to  the  distance  between  the 
latter  and  the  analyzer  diaphragm.  It  is  always  good  to  place 
a  screen  immediately  in  front  of  the  light,  and  to  choose  its 
size  so  that  the  image  of  the  opening  in  this  screen  on  the 
analyzer  diaphragm  is  a  little  larger  than  this  diaphragm. 

If  the  diameter  n  of  the  telescope  objective  is  taken  large 
enough,  all  the  rays  coming  from  the  analyzer  diaphragm  will 
pass  through  it,  and  it  only  remains  to  provide  that  these  rays 
actually  reach  the  pupil  of  the  observer's  eye,  as  the  two  dia- 
phragms of  the  ocular  and  eye-piece  cap  may  always  be  chosen 
large  enough.  In  order  to  secure  the  first  it  is  simplest  to 
arrange  the  construction  so  that  the  pupil  may  be  brought 
exactly  in  the  plane  of  the  ocular  circle,  or,  more  accurately  stated, 
in  the  plane  of  the  image  of  the  analyzer  diaphragm  produced 
by  the  telescope.  By  rightly  choosing  the  magnification  it  is 
easily  possible  to  keep  the  ocular  circle  within  a  diameter  of 
about  4  mm.,  so  that  all  rays  may  pass  through  the  pupil. 
But  it  is  not  even  necessary  to  keep  the  ocular  circle  smaller 
than  the  pupil,  because  the  shutting  off  of  the  part  of  the 


324  POLARIZATION  APPARATUS 

circle  outside  of  the  edge  of  the  pupil  will  not  alter  in  any 
manner  the  distribution  of  the  illumination  as  it  appears  on 
the  polarizer  diaphragm,  since  the  ocular  circle  is  the  image 
of  the  analyzer  diaphragm,  and  therefore,  at  the  same  time, 
the  image  of  the  source  of  light.  A  part  of  the  light  may, 
therefore,  be  screened  off  by  the  pupil,  which,  as  explained 
above,  decreases  the  total  intensity  of  illumination  of  the  field, 
but  does  not  change  its  uniformity.  But  in  order  to  keep  the 
field  of  view  as  bright  as  possible,  it  is  always  preferable  to 
keep  the  ocular  circle  smaller  than  the  pupil.  It  follows  also 
that  as  long  as  the  pupil  is  kept  in  the  plane  of  the  ocular  circle, 
changes  in  the  position  of  the  eye  may  be  as  great  as  desirable 
without  altering  the  uniform  distribution  of  illumination  of  the 
field  of  view.  But  the  case  is  quite  different  if  the  pupil  is  not 
brought  into  the  plane  of  the  ocular  circle,  because  now  the 
bundles  of  rays  from  different  parts  of  the  field  of  view  may 
be  unevenly  screened  or  obscured  by  the  pupil,  in  consequence 
of  which  the  illumination  of  the  field  may  no  longer  appear 
uniform.  Therefore  only  astronomical  telescopes  with  con- 
vergent oculars  may  be  used,  while  the  ordinary  Galilean  tele- 
scope, in  which  the  ocular  circle  lies  within  the  instrument, 
should  be  avoided  ;  commonly  a  magnification  of  four  to  six 
diameters  is  chosen.  In  order  to  be  able  to  bring  the  pupil 
with  certainty  within  the  plane  of  the  ocular  circle,  the  eye- 
piece cap  must  be  always  so  attached  that  the  circle  is  formed 
a  little  beyond  it ;  the  pupil  will  then  lie  in  the  ocular  circle 
plane  when  the  eye  is  held  pretty  close  to  the  eyepiece  cap. 

If  in  this  way  a  perfectly  normal  path  of  the  light  rays 
through  the  apparatus  and  to  the  eye  of  the  observer  is  pro- 
vided for,  no  zero  point  or  observation  errors  will  be  occa- 
sioned by  changes  in  the  illumination  flame  or  by  deviations 
in  the  rays  themselves.  It  has  thus  far  been  assumed  that  no 
rotating  substance  is  in  the  apparatus,  which  is  the  case  in  the 
zero  point  adjustment.  But  if  this  condition  is  not  true,  as, 
for  example,  when  a  substance  with  refractive  index  greater 
than  that  of  the  air  is  present  in  appreciable  length  (a  filled 
tube ) ,  then  the  course  of  the  rays  as  outlined  will  no  longer 
exactly  hold  true.  In  order  to  focus  the  telescope  sharply  on  the 
polarizer  diaphragm,  the  eyepiece  must  be  adjusted  again,  and 


MAKING    THE   OBSERVATION  325 

the  image  of  the  source  of  light  will  no  longer  be  formed  at  the 
analyzer  diaphragm.  It  may,  however,  be  easily  provided  for 
that  the  path  of  the  light  shall  remain  perfectly  correct  when 
the  zero  point  determination  is  made  and  also  when  a  filled 
tube  is  in  position,  which  question,  however,  will  not  be  taken 
up  in  detail  at  this  time. 

The  rotating  substances  and  observation  tubes  must  be  per- 
fectly centered  with  reference  to  the  axis,  and  care  should  be 
taken  to  have  the  diaphragms  on  the  observation  tubes  some- 
what larger  than  the  polarizer  and  analyzer  diaphragms,  in 
order  that  none  of  the  light  rays  normally  in  the  field  of  view 
may  be  screened  off.  Finally,  it  may  be  remembered  that  it  is 
an  error  to  place  lenses,  or  glass  vessels  with  absorbing  liquids 
to  purify  the  light,  between  the  polarizer  and  analyzer. 

97.  Making  the  Observation. — In  order  to  avoid  repetitions  in 
the  descriptions  of  apparatus,  the  general  method  of  carrying 
out  an  observation  will  be  explained  here.  Take  first  the  case 
of  measuring  the  angle  of  rotation  of  a  substance  with  an 
instrument  which  has  two  zero  points  180°  apart.  After  the 
light  is  so  arranged  that  a  sharp  image  of  the  screen  opening 
in  front  of  it  is  thrown  on  the  polarizer  diaphragm  by  the 
illumination  lens,  the  telescope  is  sharply  focused  on  the 
polarizer  diaphragm.  By  now  rotating  the  analyzer  several 
zero  point  observations  are  made  at  each  side  of  the  graduated 
circle,  and  in  all  more  exact  work  both  verniers  should  be 
always  read  off.  After  inserting  the  rotating  substance  the  tele- 
scope is  again  sharply  focused.  On  again  making  a  sufficient 
number  of  adjustments  and  readings  on  both  verniers,  and 
then  more  readings  of  the  zero  point  after  removal  of  the 
active  substance,  we  obtain  by  subtraction  a  mean  value  of  the 
angle  of  rotation  from  which  the  eccentricity  of  the  gradu- 
ated circle  is  eliminated.  If  now  the  observations  are  repeated, 
starting  with  the  second  zero  point  180°  from  the  first,  the  same 
angle  of  rotation  should  be  found,  provided  the  polarization 
prisms  are  properly  constructed  and  centered,  and  the  angle 
of  rotation  itself  has  not  changed.  Otherwise  the  mean  of 
the  two  values  must  be  taken  and  this  considered  as  the  true 
angle  of  rotation.  Between  the  different  observations  it  is 
well  also  to  rotate  the  substance  or  polarization  tube  in  order 


326 


POLARIZATION    APPARATUS 


to  compensate  errors  which  may  arise  from  imperfect  parallel- 
ism in  the  end  surfaces  of  the  observed  substance.  With  the 
Wild  polaristrobometer  one  must  naturally  make  readings,  in 
all  accurate  work,  in  each  of  the  four  quadrants  of  the  circle 
and  then  take  the  mean  of  the  four  angles  so  determined. 

If  the  rotation  of  a  cane-sugar  solution  is  to  be  found  by  the 
aid  of  a  saccharimeter,  the  light  is  arranged,  as  before,  so  that 
a  sharp  image  of  the  front  screen  is  formed  by  the  illumin- 
ating lens  at  the.  analyzer  diaphragm.  From  the  zero  point 
reading  and  those  made  after  placing  the  polarizing  tube  in 
position,  the  rotation  is  obtained  by  subtraction.  Between 
readings  the  tube  should  be  rotated  around  its  axis.  In 
technical  work  where  numerous  observations  are  made,  one 
after  the  other,  a  few  readings  are  sufficient  to  secure  exact  re- 
sults ;  it  is  also  enough  to  determine  the  zero  point  every  hour. 
In  order  to  keep  all  outside  light  from  the  instrument  the 
room  should  be  at  least  partly  darkened  ;  and  in  general  it 
may  be  said  that  the  darker  the  room  the  greater  is  the 
accuracy  in  observation. 

of.    Older  Forms  of  Apparatus: 
i.  Biot  (MitscherlicJt}  Polariscope.1 

98.  Description  of  the  Instru- 
ment.— This,  the  simplest  of  all 
polaristrobometers,  first  made 
by  Biot,  and  which  was  referred 
to  in  §92,  consisted  of  a  stand, 
polarizer,  analyzer,  and  gradu- 
ated circle.  Later,  the  polar- 
izer was  provided  with  a  small 
circular  diaphragm  to  which 
the  eye  was  to  be  accommoda- 
ted, and  in  order  to  increase 
the  intensity  of  the  illumina- 
tion, a  small  double  convex 
lens  was  added  in  front.  The 
Mitscherlich  apparatus  is 
shown  in  Fig.  31.  The  two 
polarization  prisms  are  at- 
tached at  the  ends  of  a  hori- 

Mitscherlich  :   "  I,ehrbuch  der 


FIR. 


'  Biot:    Ann.    chim.    phys.,    [2],    74,   401    (1840) 
Chemie,"  4th  ed.,  i,  361  (1844). 


OBSERVATION  WITH    HOMOGENEOUS   LIGHT  327 

zontal  bar  of  brass  or  wood.  The  polarizer  and  the  illumina- 
tion lens  are  found  in  a  brass  tube  a,  which  may  be  rotated,  if 
necessary,  and  then  made  fast  by  turning  the  small  screw  e.  The 
supporting  frame  of  the  analyzer  b,  which  may  be  rotated,  is  fur- 
nished with  a  handle,  c,  and  two  pointers,  which  have  either  a 
simple  index  mark  or  vernier,  and  which  move  over  the  fixed 
graduated  circle.  The  divisions  are  in  degrees,  and  the  read- 
ings may  be  made  to  tenths  of  a  degree.  The  polarization  tube 
may  be  laid  in  between  the  two  prisms  and  has»  usually  a  length 
of  20  cm.  If  the  pointers  are  furnished  with  verniers,  the 
alidades  to  the  right  and  the 
left  of  the  index  zero  are  divi- 
ded, so  that  10  divisions  on  the 
scale  equal  9°  on  the  circle, 
which  permits  a  direct  reading  , 

to  one-tenth  degree.   In  the  ad- 
joining Fig.  32,  the  zero  of  the 

vernier  does  not  quite  reach  the  third  degree  mark  on  the  cir- 
cle, to  the  right,  and  the  sixth  vernier  mark  is  the  first  one 
which  makes  a  coincidence.  The  alidade  reading  is,  therefore, 
4-2.6°.  A  further  improvement  in  the  Mitscherlich  instru- 
ment was  the  addition  of  a  small  reading  telescope  in  front  of 
the  analyzer. 

99.  Observation  with  Homogeneous  Light. — In  the  use  of  the 
apparatus  it  is  preferable  to  employ  homogeneous,  yellow 
sodium  light,  and  so  find  the  rotation  for  the  ray  D.  To  find 
the  zero  point,  the  polarization  tube  is  placed  in  position,  either 
empty  or  filled  with  water,  and  then  the  analyzer  is  turned 
until  the  position  of  maximum  darkness  is  reached.  If  the 
round  field  of  view  is  at  all  large,  complete  darkening  of  the 
whole  field  does  not  occur,  but  a  black  band  is  ob- 
served,1 the  edges  of  which  grow  gradually  lighter 
(Fig.  33),  and  this  is  brought  as  nearly' as  possible 
to  the  center  of  the  field  by  moving  the  analyzer. 
On  repeating  this  several  times  and  taking  the  mean 
of  the  readings,  the  true  zero  point  is  found.  If  it  is  desired 

1  For     the     theory     of    this,     see      I<ippich,      "  Ueber       polaristrobometrische 
Methoden,"  Wien.  Sitzungsber.,  II,  85,  268  (1882). 


(D 


328 


POLARIZATION   APPARATUS 


to  have  this  coincide  as  nearly  as  possible  with  the  zero  of  the 
graduation,  which  is  not  at  all  necessary,  the  index  is  first 
brought  to  zero,  and  then,  after  loosening  the  screw  e  (Fig.  31 ), 
the  polarizer  is  turned  until  the  black  band  appears  in  the  mid- 
dle. Ordinarily,  this  adjustment  is  carried  out  by  the  maker 
of  the  instrument. 

If  now  the  observation  tube  filled  with  the  active  liquid  is 
placed  in  position  the  field  of  view  appears  bright  again,  and 
it  is  necessary  to  turn  the  analyzer  through  a  certain  angle, 
equal  to  the  angle  of  rotation  of  the  substance,  to  cause  the 
reappearance  of  the  dark  band.  This  is  repeated  for  the 
position  1 80°  distant.  Concerning  the  observations  and  deter- 
mination of  direction  of  rotation  see  §93  and  §97.  The 
mean  error  in  the  readings  is  about  zb  o.  i°. 

This  form  of  apparatus  is  employed  at  the  present  time  only 
in  the  determination  of  rotation  dispersion. 

2 .  Robiquet '  s  Pola  ri scope 

100.  Description  of  the  Instrument.  —  Robiquet  made  the 
Mitscherlich  apparatus  much  more  sensitive  by  adding  to  the 


34- 


polarizer  the  double  quartz  plate,  constructed  by  Soleil,  the 
theory  of  which  is  given  in  the  next  paragraph.  Robiquet's 
instrument  is  shown  in  Fig.  34.  A  brass  trough  with  a  sec- 
tion of  half  a  circle,  a  b,  which  may  be  covered  by  a  corre- 


THEORY   OF   THE   SOLEIL   DOUBLE    PLATE  329 

spending  lid,  c,  forming  a  tube,  carries  at  one  end  in  a  fixed 
shell  the  polarizing  Nicol,  d.  In  front  of  this  is  the  illumi- 
nation lens  e,  and  at  the  other  side,  at  f ,  the  Soleil  double  plate. 
At  the  other  end  of  the  trough  is  the  rotating  analyzer  g,  and 
a  small  Galilean  telescope,  consisting  of  the  objective  h  and 
the  ocular  i.  The  analyzer  is  turned  by  aid  of  the  lever  k ; 
the  angle  of  rotation  is  read  off  on  the  graduated  circle  1. 
Glass  tubes,  p  p,  containing  the  liquid  to  be  examined  are  laid 
in  the  trough.  The  whole  is  supported  on  the  stand  o. 

101.  Theory  of  the  Soleil  Double  Plate. — The  biquartz  consists 
of  two  equally  thick  quartz  plates,  one  of  which 
is  left  rotating,  the  other  right  rotating,  cut  vertically 
to  the  optical  axis  and  cemented  together.  The  last 
grinding  and  polishing  are  carried  out  after  the  pieces  are 
cemented  together,  in  order  to  have  them  of  the  same  thick- 
ness exactly.  If  linearly  polarized  white  light  falls  now 
upon  the  double  plate  from  the  polarizer,  it  will  exhibit,  in 
consequence  of  the  rotation  dispersion  in  going  through  the 
plate,  a  series  of  colored  bands  to  each  side  of  the  center.  The 
analyzer  following  will  not  allow  those  rays  to  pass,  whose 
plane  of  polarization  coincides  with  the  principal  section  of  the 
analyzer.  If  these  are  the  yellow  rays,  those  remaining  which 
pass  through,  yield  a  mixed  color  of  a  pale  blue  violet  shade, 
which,  with  the  slightest  turn  in  the  analyzer,  turns  to  either 
red  or  blue,  and  which  is  designated  as  the  sensitive  or  tran- 
sition tint  (teinte  de  passage).  Inasmuch  as  the  two  halves 
of  the  biquartz  can  have  the  same  color  only  when  the  princi- 
pal sections  of  the  polarizer  and  analyzer  are  parallel  or  per- 
pendicular to  each  other,  the  two  quartz  plates  are  given  such 
a  thickness  that  they  rotate  the  yellow  rays  to  the  right  and 
to  the  left  exactly  90°  or  180°.  For  the  first,  the  thickness 
must  be  3.75  mm.,  since  Biot  found  that  i  millimeter  of  quartz 
rotates  mean  yellow  light  through  24°,  and  we  have  then  the 
proportion,  24°:  i  1:90°  13. 75.  In  this  case,  the  principal 
sections  of  the  polarizer  and  analyzer  must  be  parallel  to  secure 
the  transition  tint.  If  the  biquartz,  on  the  other  hand,  is  7.5 
mm.  thick,  so  that  the  yellow  rays  are  rotated  through  180°, 
then  the  transition  tint  will  appear  by  crossed  position  of  the 
Xicols.  If  the  analyzer  is  now  turned  a  little  from  its  vertical 


330  POLARIZATION    APPARATUS 

or  parallel  position  with  reference  to  the  polarizer,  one-half  of 
the  field  will  appear  blue,  the  other  distinctly  red.  This 
simultaneous  appearance  of  the  red  and  blue  colors  makes  the 
observation  with  the  Robiquet  apparatus  more  sensitive  than 
where  light  and  shade  folloiv  each  other,  as  is  the  case  in  the 
Mitscherlich  apparatus. 

102.  The  Observation. — The  Robiquet  apparatus  requires 
white  light  and  furnishes  us  with  the  angle  of  rotation  for 
mean  yellow  light,  which,  following  Biot's  suggestion,  is 
represented  by  ofj.  Although  the  position  of  the  line  sep- 
arating the  two  halves  of  the  double  quartz  is  a  matter  of 
indifference,  the  latter  is  generally  so  placed  that  the  division 
is  vertical.  The  telescope  is  sharply  focused  on  this  line  of 
separation  by  proper  movement  of  the  ocular.  The  obser- 
vation tube  is  not  yet  to  be  placed  in  position.  By  turning 
the  analyzer  it  is  a  simple  matter  to  bring  out  the  transition 
tint  as  a  perfectly  uniform  shade  on  the  two  halves  of  the 
field.  The  position  of  the  analyzer  corresponds  then  to  one 
zero  point  of  the  instrument ;  the  other  zero  point  is  separated 
from  this  by  180°.  If  now  the  tube  containing  the  active 
liquid  is  placed  in  the  trough  the  uniformity  of  color  dis- 
appears. The  analyzer  is  then  to  be  turned  until  the  equality 
of  the  shades  on  the  two  halves  of  the  image  returns  ;  the 
angle  through  which  the  analyzer  had  to  be  turned  is  equiv- 
alent to  the  angle  of  rotation  of  the  substance,  af.  But  the 
latter  must  not  be  too  large,  because  it  could  then  happen  that 
the  transition  tint  would  no  longer  be  sharply  defined.  On 
the  relation  of  angles  of  rotation,  otj  and  atD,  see  §  152. 

In  order  to  recognize  whether  the  active  substance  is  right- 
rotating  or  left,  it  is  necessary  to  determine,  once  for  all,  with 
the  particular  instrument,  the  position  of  the  red  or  blue  field 
when  a  body  with  known  direction  of  rotation,  right  rotating 
cane-sugar  for  instance,  is  between  the  Nicols.  If  the  sub- 
stance under  investigation  shows  the  same  arrangement  of  the 
two  colors  it,  likewise,  must  be  right-rotating  ;  if,  on  the  other 
hand,  the  shades  are  reversed,  the  body  must  be  left  rotating. 
In  addition,  with  a  right-rotating  body,  uniformity  of  color  on 
the  two  halves  of  the  field  reappears  when  the  analyzer  is 
turned  in  the  clock -hand  direction,  while  with  a  left-rotating 
body  the  motion  of  the  analyzer  must  be  the  reverse. 


DESCRIPTION  OF  THE  WILD  INSTRUMENT  331 

The  mean  error  of  a  reading  is  about  ±  4  minutes  of  arc. 

The  apparatus  of  Robiquet  suffers  from  several  drawbacks. 
In  the  first  place  it  gives  a  determination  of  otj  only  and  can 
not  be  used  for  homogeneous  light.  Secondly,  an  absolutely 
accurate  determination  of  the  angle  of  rotation  is  not  possible, 
because  after  putting  the  observation  tube  in  position, 
especially  if  the  liquid  is  somewhat  colored,  the  transition  tint 
never  shows  exactly  the  same  shade  that  appeared  in  the  zero 
point  determination,  and  in  consequence  of  this,  indeterminable 
systematic  errors  are  introduced.  Finally,  the  readings  maybe 
quite  inaccurate  with  those  deficient  in  a  sharp  sense  of  color, 
and  for  the  color-blind  the  use  of  the  apparatus  is  impossible. 
For  these  several  reasons  it  is  scarcely  used  at  present,  and  can 
be  employed  at  most  only  for  approximate  determinations  of 
the  rotation. 

j.    Wild' s  Polaristrobometer.1 

103.  Description  of  the  Instrument. — This  instrument,  which 
was  brought  out  by  Wild  in  1864,  but  which  to-day  finds  only 


Fig.  35- 

limited  use,  gives  much  closer  results  than  either  of  the  pre- 
viously described  polariscopes.  The  peculiar  feature  of  the 
instrument  consists  in  this,  that  a  Savart  polariscope  is  placed 
between  the  polarizer  and  analyzer,  the  former  of  which  may 
be  rotated ,  and  this  combination  gives  rise  to  a  series  of  dark 
bands  which  disappear  with  a  certain  position  of  the  polarizer. 
This  point,  which  may  be  sharply  observed,  is  the  one  looked 
for  in  making  the  readings.  For  light,  the  sodium  flame  is 
commonly  used,  but  any  homogeneous  light  may  be  employed. 
The  arrangement  of  the  instrument  is  shown  in  Figs.  35  and 

1  Wild  :  Ueber  ein  neues  Polaristrobometer,  Berne,  1865. 


332  POLARIZATION    APPARATUS 

36.     The  identical  parts  are  shown  by  small  letters  in  Fig.   35 
and  by  large  letters  in  Fig.  36. 

A  bar  of  brass,  Y,  which  is  supported  on  a  stand,  X,  and 
which  may  be  moved  either  vertically  or  horizontally,  carries 
at  one  end  the  polarizing,  and  at  the  other,  the  analyzing, 
appliance.  Light  passes  into  the  tube  b  through  a,  and  reaches 
the  polarizer  d  through  the  round  diaphragm  c  which  has  a 
diameter  of  about  10  mm.  The  brass  work  holding  these 

I 


Fig.  36. 

pieces  is  rigidly  attached  to  the  graduated  circle  e  and  may 
be  rotated  with  this,  around  an  axis.  The  polarized  rays  pass 
through  the  observation  tube  f  and  enter  then  into  the  fixed 
ocular  part.  This,  the  so-called  polariscope,  contains  first,  at 
g,  the  arrangement  which  produces  the  sensitive  interference 
bands,  consisting  of  two  Iceland  spar  plates  3  mm.  in  thickness, 
cemented  together.  These  plates  are  cut  so  as  to  make  an 
angle  of  45°  with  the  optical  axis  and  are  then  laid  together  in 
such  a  manner  that  their  principal  sections  cross  at  right 
angles.  Two  lenses,  h  and  i,  follow,  making  a  telescope  of  low 
magnifying  power  (about  5  diameters),  with  adjustment  for 
focusing  the  latter  upon  distant  objects.  A  round  diaphragm,  k, 


OBSERVATION  WITH  THE  WILD  INSTRUMENT  333 

holding  cross  hairs  in  X  position,  and  having  an  opening  of 
about  4  mm.,  is  placed  between  the  two  and  in  the  focus  of  h. 
Finally  comes  the  analyzer  1,  which  is  ordinarily  so  fastened 
that  its  principal  section  stands  horizontally.  The  crossed 
principal  sections  of  the  double  plates  g,  must  make  angles  of 
45°  with  the  latter.  In  order  that  the  positions  of  the  two 
parts  g  and  1  may  remain  fixed  with  reference  to  each  other, 
the  draw-tube  of  the  ocular  in  which  the  nicol  1  and  lens  i  are 
placed,  is  furnished  with  a  guide.  The  whole  polariscope  is 
contained  in  a  shell  Z,  attached  to  the  bar  Y,  and  may  be 
rotated  through  a  small  angle.  For  this  purpose  the  shell  has 
a  widened  guide  slit  and  two  set  screws,  m  m,  which  hold 
between  them  a  small  projecting  piece  standing  out  from  the 
polariscope  tube.  This  last  arrangement  serves  for  the  adjust- 
ment of  the  zero  point  of  the  apparatus.  At  n  a  round  disk 
screen  is  fastened  which  keeps  outside  light  away  from  the 
eye  of  the  observer. 

In  order  to  rotate  the  polarizer  d,  the  setting  holding  it,  along 
with  the  attached  circular  disk,  fits  into  a  solid  ring  fastened 
to  the  bar  Y.  On  the  side  of  the  disk  toward  the  observer 
there  is  a  toothed  wheel  into  which  the  small  pinion  wheel  o 
works,  and  this  is  operated  through  the  rod  q  by  means  of  the 
button  p.  Near  the  periphery  of  the  disk  there  is  a 
circular  graduation,  adjoining  which  is  a  fixed  vernier  or  simple 
index  r.  The  graduation  may  be  read  by  aid  of  the  telescope 
s  which  consists  of  the  adjustable  ocular  t  and  the  objective 
lens  u.  At  the  end  of  the  telescope,  at  v,  there  is  a  small 
inclined  mirror,  with  round  opening  in  the  center,  which 
serves  to  reflect  light  on  the  scale  from  a  small  flame  carried 
on  the  arm  w.  Finally,  it  should  be  mentioned,  the  instru- 
ment is  usually  made  to  hold  observation  tubes  up  to  22  cm.  in 
length. 

104.  The  Observation. — In  carrying  out  an  observation,  after 
putting  an  empty  tube  in  the  apparatus  to  find  first  the  zero 
point,  the  polariscope  ocular  is  drawn  out  until  the  cross  hairs 
are  sharply  defined.  The  polarizer  is  now  turned  by  aid  of 
the  button  p  (Fig.  35),  until  a  position  is  found  in  which  the 
illuminated  field  appears  to  contain  a  number  of  parallel  dark 


334  POLARIZATION    APPARATUS 

bands  or  fringes  (Fig.  37,  a).  By  continued  turning  these 
begin  to  fade  out,  and  finally  a  point  is  reached  where  a  clear 
part,  free  from  bands,  runs  through  the 
field.  By  a  slight  motion  of  the  button 
to  and  fro,  this  bright  part  is  brought  as 
nearly  as  possible  to  the  middle  of  the 
field  leaving,  on  each  side  of  the  cross 
hairs  and  equally  distant  from  the  center, 
parts  of  the  fringes  still  visible.  This  po- 
sition is  the  one  at  which  a  reading  of 
the  graduation  is  made.  If  the  polarizer 
is  turned  further  the  bands  become 
stronger  to  a  certain  maximum,  then 
weaker  followed  by  disappearance,  and  in 
a  complete  rotation  of  the  circle  this  phe- 
nomenon is  repeated  four  times  at  intervals  of  90°. l  Ordina- 
rily in  each  one  of  these  positions  the  remaining  fringes  show 
some  characteristic  form  which  should  be  remembered.  The 
extinction  of  the  bands  corresponds  to  those  positions  of  the 
polarizer  at  which  its  principal  section  coincides  with  the 
principal  section  of  one  of  the  crossed  pieces  in  the  Savart 
double  plate,  while  the  greatest  intensity  of  the  fringes  is  found 
when  these  sections  make  an  angle  of  45°  with  each  other. 

If  it  is  found  that  the  bright  part  of  the  field  is  so  broad  that 
the  fringes  right  and  left  from  the  center  no  longer  show,  then 
the  luminosity  of  the  source  of  light  must  be  diminished  until 
the  portion  free  from  bands  has  grown  narrow  enough.  The 
decrease  in  the  width  of  the  portion  free  from  fringes  follows 
from  this,  that  the  eye,  on  diminishing  the  total  illumination, 
acquires  greater  sensitiveness  in  recognizing  differences  in 
intensity,  and  may  therefore  follow  the  fringes  further  to  the 
points  at  which  they  totally  disappear,  than  would  be  possible 
with  a  brighter  field. 

If  the  movable  Nicol  is  brought  to  one  of  the  four  zero  points, 
and  the  empty  tube  replaced  by  one  filled  with  an  active  liquid, 
tlu-  interference  bands  appear  anew.  On  passing  through  the 
active  layer,  the  plane  of  polarization  is  rotated  through  a  cer- 
tain angle,  and  in  order  to  place  this  again  parallel  with  one  of 

1  For  the  theory  of  these  bands  see  Wiillner's  "  Iyehrlmch  der  Physik.,"  4th  ed  ,  a, 
p.  650. 


HALF-SHADOW    INSTRUMENTS 


335 


the  principal  sections  of  the  Savart  double  plate,  the  polarizer 
must  be  turned  through  an  equal  angle  in  the  opposite 
direction.  The  disappearance  of  the  bands  follows  then  as 
before.  The  angle  through  which  the  polarizer  must  be 
moved  to  bring  about  the  extinction  of  the  bands  is, 
therefore,  the  angle  of  rotation  of  the  body  placed  between  the 
Xicols.  The  circular  disk  must  consequently  be  turned  in  a 
direction  opposite  to  the  clock- hand  motion  when  the  body  is 
right  rotating  and  vice  versa.  In  respect  to  the  button  P  p, 
Figs.  35  and  36,  on  \which  the  hand  of  the  observer  rests,  the 
motion  here  corresponds  with  the  direction  of  rotation  of  the 
substance.  If  the  figures  on  the  circle,  like  those  on  a  clock 
face,  run  from  left  to  right,  as  is  usually  the  case,  the  readings 
with  a  right  rotating  body  give  larger  numbers  and  those  with 
a  left-rotating  body  smaller  numbers  than  are  shown  in  finding 
the  zero  point.  In  regard  to  the  method  of  observation  and 
determination  of  the  direction  and  amount  of  rotation,  see  §97 
and  §  93. 

The  mean  error  of  a  reading  is  about  ±  three  minutes  of  arc. 

ft.  Half -Shadow  Instruments. 

105.  Principle  of  the  Half-Shadow  Apparatus. — In  these  polar- 
istrobometers,  the  characteristic  sensitive  part  is  so  constructed 
that  the  field'  of  view  is  divided  into  two  or  more  surfaces, 
which,  with  a  definite  position  of  the  an-  A  E  B 

alyzer,  show  a  uniform  degree  of  partial 
shadow.  This  point  is  employed  in  the 
observation.  On  account  of  the  rela- 
tively low  luminosity  of  the  field  in  the 
neighborhood  of  this  point,  these  instru- 
ments have  received  the  name  of  half- 
shadow  apparatus  (polarimetres  a  pe- 
nombre). 

The  half-shadow  instruments  all  con- 
tain an  illumination  lens,  the  polarizing 
appliance,  which  does  not  consist  in  a 
simple  nicol  alone,  the  analyzer,  and  a  reading  telescope.  To 
take  the  simplest  case  first,  let  us  consider  the  polarizer  so  made 
that  it  furnishes  a  field,  A  B  C  D  (Fig.  38),  which  appears  to 


F 
Fig.  38. 


POLARIZATION    APPARATUS 

be  divided  into  two  halves  by  the  line  E  F,  and  in  such  a 
manner  that  all  rays  coming  from  the  surface  A  E  F  D 
are  linearly  polarized  in  the  direction  of  G  H,  while  all 
rays  which  come  from  E  B  C  F  are  linearly  polarized 
in  the  direction  G  J.  According  to  §91,  the  polarizer 
will  pass  always  such  rays  only  as  are  polarized  ver- 
tically to  its  principal  section.  Let  now  G  H  =  a  and 
G  J  =  b  represent  also  the  amplitude  of  the  light  vibrations, 
which,  in  reality,  as  will  be  seen  later,  never  differ  much  from 
each  other.  The  angle  H  G  J  =  ",  which  the  two  directions 
of  polarization  make  with  each  other,  is  usually  made  smaller 
than  about  10°.  Imagine  the  analyzer  turned  so  that  its  prin- 
cipal section  G  K  falls  within  the  angle  **,  and  represent  the 
angle  H  G  K  by  ft.  Then,  when  L  M  is  perpendicular  to 
G  K,  the  analyzer  allows  of  a  the  component  G  N  =  a  sin  ft 
to. pass,  and  of  the  vibrations  b  the  component  G  O  ==  b  sin 
(a — /?).  The  smaller  the  angle  a  is  made,  the  smaller  these 
two  components  become  ;  that  is,  the  greater  becomes  the 
shadow  on  the  field  of  view  ;  the  angle  a  is,  therefore,  briefly 
termed  the  half -shadow.  It  appears  further  that  for  ft  =  o, 
G  N  =  o  ;  that  is,  when  the  principal  section  of  the  analyzer 
coincides  with  the  direction  of  polarization  on  the  surface 
A  E  F  D,  then  the  surface  becomes  perfectly  dark  ;  likewise, 
G  O  =  o  for  ft  =  of ;  that  is,  the  surface  E  B  C  F  becomes 
perfectly  dark  when  the  analyzer  principal  section  coincides 
with  its  direction  of  polarization.  The  half  shadow  a  may  be 
most  simply  and  easily  found  when  the  analyzer  is  so  turned 
that  the  one  surface  is  perfectly  dark,  and  then  until  the  other 
surface  is  in  the  same  way  obscured  ;  the  angle  between  the 
two  positions  is  equal  to  the  half-shadow  a. 

As  remarked  above,  in  making  an  observation  with  a  half- 
shadow  instrument,  the  point  for  final  reading  is  sought  when 
the  two  surfaces  show  exactly  the  same  degree  of  illumination. 
This  is  the  case  when  G  N  -  G  O  or  tan  /?  —  b  sin  a  /  (a  -f- 
b  cos  «).  From  this  equation  a  definite  value  for  ft  follows  ; 
there  is,  therefore,  only  one  position  of  the  analyzer  at  which 
the  field  shows  an  absolute  uniformity  of  shadow.  Uniform 
illumination  is  exhibited  also  when  the  analyzer  is  turned 
through  1 80°  from  this  first  position,  as  then  the  principal 


HALF-SHADOW    INSTRUMENTS  337 

section  has  the  same  position  as  before.  Accordingly,  all  half- 
shadow  instruments  possess  two  zero  points  180°  apart.  If 
the  principal  section  of  the  analyzer  is  turned  out  of  the  half- 
shadow  angle  a  and  parallel  to  the  junction  line  of  H  J,  it  will 
follow,  too,  that  in  this  case  the  illumination  of  the  two  halves  of 
the  surface  will  be  the  same,  but  the  light  is  so  little  weakened 
by  the  analyzer  that  the  whole  field  appears  now  very  bright. 
But  the  eye  is  not  able  to  distinguish  slight  differences  in 
illumination  between  two  bright  lights,  and  for  this  reason  the 
position  of  the  principal  section  parallel  to  H  J  cannot  be  em- 
ployed in  the  observations.  On  the  other  hand,  when  the 
principal  section  is  at  its  zero  position  within  the  small  half- 
shadow  angle,  the  field  is  pretty  dark.  The  intensities  of  the 
light  passing  the  analyzer  from  the  two  surfaces  are  to  be 
taken  as  proportional  to  the  squares  of  the  two  amplitudes, 
G  N  and  G  O,  as  the  vibrations  take  place  simultaneously  in 
the  same  medium.  But  these  amplitudes,  because  of  the  small 
value  of  a,  are  very  small  as  compared  with  the  amplitudes  a 
and  b.  If  then,  the  analyzer  is  turned  but  very  little  from  its 
zero  position,  the  one  surface  will  become  brighter  and  the 
other  darker,  which  the  eye  can  sharply  recognize,  because  of 
the  slight  general  intensity  of  the  whole  field.  As  the  polar- 
izing arrangements  in  all  half-shadow  instruments  are  so  made 
that  a  and  b  are  very  nearly  the  same,  it  follows  from  the 
above  equation  that  in  the  zero  position  ft  is  always  nearly 

equal  — .     The  analyzer  principal  section  is  then  always  so 

adjusted  that  it  very  nearly  bisects  the  half-shadow  angle. 

As  can  be  seen,  the  form  of  the  two  surfaces,  the  dividing 
line  between  them  and  their  relative  positions  to  each  other, 
do  not  come  at  all  into  consideration.  One  surface  may  lie 
wholly  within  the  other,  and  the  line  between  them  be  then  a 
circle  ;  or  we  can  imagine  to  the  right  of  the  surface  E  B  C  F 
another  surface  which  shall  have  the  same  properties  as  the 
surface  A  E  F  D ;  that  is,  its  light  polarized  in  the  direction 
G  H.  We  have  now  a  field  of  view  in  three  parts,  in  which 
the  three  surfaces  must  show  the  same  degree  of  illumination 
when  again  the  principal  section  of  the  analyzer  bisects  the 
half -shadow  angle.  As  will  be  seen,  all  these  cases  have  been 
applied  in  practice  in  the  most  different  ways. 
22 


338  POLARIZATION    APPARATUS 

106.  Influence  of  the  Source  of  Light. — In  all  the  following  con- 
siderations, for  the  sake  of  simplicity,  we  shall  assume  a  field 
of  view  with  double  surface,  as  the  explanations  hold  good,  or 
at  most  with  very  slight  exceptions,  for  fields  with  more  di- 
visions. If  we  illuminate  a  half-shadow  apparatus  with 
homogeneous  light  of  definite  wave-length,  bring  the  analyzer 
to  the  zero  point  so  that  the  two  fields  show  the  same  intensity, 
and  then  insert  an  active  substance,  the  two  directions  of 
polarization  will  be  turned  through  exactly  the  same  angle  by 
the  latter.  The  half-shadow  angle  a  remains,  therefore,  con- 
stant. To  find  now  the  amount  of  rotation  of  the  two  planes 
of  polarization,  the  analyzer  is  turned  until  the  field  of  view 
becomes  uniformly  shaded  as  at  the  start.  If  now  the  prin- 
cipal section  of  the  analyzer  should  not  have  exactly  the  same 
position  with  reference  to  the  two  planes  of  polarization,  which 
it  had  when  the  zero  point  was  found,  a  systematic  error  must 
obtain  somewhere  and  the  angle  of  rotation  of  the  analyzer 
would  not  give,  directly,  the  rotation  of  the  two  planes  of 
polarization.  The  principal  section  will  maintain  its  relative 
position  to  the  two  planes  of  polarization  only  when  the  rela- 
tion of  the  intensities  of  the  light  in  the  two  fields  is  not 
altered  by  the  active  substance.1  But  this  obtains  for  homo- 
geneous light  as  the  two  intensities  are  weakened  by  reflection 
at  the  end  surfaces  and  by  absorption  in  exactly  the  same 
manner.  Therefore  with  homogeneous  light  the  angle,  of 
rotation  of  the  analyzer  is  equal  to  the  angle  of  rotation  of  the 
active  substance. 

This  is  the  proper  place  to  again  emphasize  how  important 
it  is,  and  especially  with  half-shadow  instruments,  to  be  cer- 
tain that  the  course  of  the  rays  through  the  whole  apparatus 
to  the  eye  of  the  observer  is  perfectly  correct.  If,  in  illus- 
tration, in  the  above  case  one  of  the  pencils  of  rays  only  were 
to  suffer  a  partial  obstruction  by  insertion  of  the  active  sub- 
stance, it  would  necessarily  follow  that  the  relation  of  the  two 
intensities  would  be  altered  and  consequently  a  change  brought 
about  in  the  zero  point  position.  It  will  be  recognized  also 
how  essential  it  is  that  the  light  which  reaches  the  polarizing 

1  According  to  §105  tan  /3  =  b  sin  a.  I  (a  +  b  cos  a),  or  tan  /3  —  sin  a  /  -r — h  cos  a)  ;  ft  is 
therefore  dependent  only  on  the  relation  a  :  b. 


INFLUENCE   OF  THE   SOURCE   OF  LIGHT  339 

mechanism,  independently  of  the  distribution  of  the  intensity 
in  the  source  of  light,  must  be  perfectly  uniform,  as  otherwise 
the  relation  of  the  two  field  intensities  would  undergo  con- 
tinuous changes.  Variations  in  the  total  intensity  of  the  light 
reaching  the  polarizer  would  then  naturally  leave  the  relation 
of  the  intensities  of  the  emerging  lights  unaltered,  and  thus 
give  rise  to  no  displacement  of  the  zero  point. 

The  question  will  now  be  discussed,  to  what  extent  the  zero 
point  is  changed  by  use  of  different  colored  lights  in  instru- 
ments, the  polarizing  mechanism  in  which,  is  unsymmetrically 
arranged.  This  is  the  case,  for  example,  in  the  Laurent  and 
Lippich  polarizers  in  which  the  light  of  one-half  of  the 
field  has  to  pass  through  one  more  prism  than  that  of  the 
other,  from  which  cause  the  intensity  of  the  first  light  is  weak- 
ened by  reflection  and  absorption.  The  relation  of  the  light 
intensities  must  therefore  vary  with  the  wave-lengths,  and 
then  the  zero  point  of  the  apparatus  also.  As  long  as  one  is 
working  with  homogeneous  light,  these  zero  point  displace- 
ments amount  to  but  a  few  seconds  of  arc,  as  may  be  readily 
found  by  calculation,  but  in  very  exact  investigations  even 
this  should  be  considered,  as  in  the  best  half-shadow  instru- 
ments the  mean  error  in  a  reading  is  counted  now  by  seconds 
only.  But  the  case  is  very  different  when  white  light  is  used, 
as  is  the  custom  in  all  half-shadow  saccharimeters.  Then  the 
light  on  one  field  is  not  only  weakened,  but  it  becomes  changed 
in  composition  also,  as  the  absorption  and  reflections  change 
with  the  wave-length.  Zero-point  variations  up  to  nine 
seconds  may  be  found  here  by  employing  white  lights  of  dif- 
ferent sources.  When  one  considers  the  difference  in  the 
composition  of  the  light  on  the  two  fields,  it  will  be  understood 
how  the  zero  point  may  be  altered  even  a  whole  minute  when 
at  any  position  between  the  polarizer  and  the  eye,  some  sub- 
stance is  placed,  for  example,  a  dichromate  plate,  which 
absorbs  some  rays  relatively  strongly.  For  this  reason,  it  is 
therefore  wrong  in  principle  in  finding  small  rotations  of 
strongly  colored  solutions,  in  order  to  escape  the  trouble  of  pro- 
curing an  intense  sodium  light,  to  examine  them  in  a  half- 
shadow  instrument  or  saccharimeter  with  white  light,  and  with 
a  degree  of  accuracy  which  is  but  a  fraction  of  the  systematic 


340 


POLARIZATION    APPARATUS 


error  from  zero-point  displacement,  which  may  also  vary  in 
differently  colored  substances.  This  method  of  finding  an 
angle  of  rotation  with  white  light  will  be  criticized  from 
another  standpoint  in  §  153. 

107.  Calculation  of  the  Sensitiveness. — The  accuracy  which  may 
be  reached  in  half-shadow  instruments,  is  measured  by  the 
delicacy  with  which  one  can  judge  of  the  uniformity  of  shade 
on  the  two  surfaces  of  the  field  of  view.  If  the  analyzer  is 
turned  through  the  small  angle  A  ft  from  the  position  in  which 
the  two  fields  appear  to  have  the  same  brightness,  the  illumi- 
nations of  the  two  fields  may  differ  by  an  amount  expressed  as 
p  per  cent.  On  the  assumption  that  in  the  zero  position,  the 
principal  section  of  the  analyzer  bisects  the  half -shadow  angle, 
it  may  be  shown  in  a  very  simple  manner  that  between  the 

quantities  a,  A  ft,    and  p,    the  relation  p  —  400 

exists,  when  J  ft  is  expressed  in  absolute  measure;  that  is,  when 


ft  /  tan  — 


90°  is  taken  as  —  . 


then  p  =  0.00194 


If  A  ft  is  measured  in   seconds  of  arc, 


ft"  /  tan  ~~  in  Per  cent. 


Let  us  assume,  in  order  to  have  an  illustration,  that  the 
brightness  of  the  field  and  the  sensitiveness  of  the  eye  will 
admit  of  a  photometric  accuracy  of  p  —  2  per  cent.,  then  it 
follows  from  the  above  formula  that  errors  in  reading  A  /? 
become  smaller  in  proportion  as  the  half  -shadow  a  is  decreased. 
In  the  following  table  are  given  certain  values  of  or,  and  the 
corresponding  values  of  J  ft,  in  seconds,  for  p  =  2  per  cent. 


a 

10° 

8° 

6° 

4° 

2° 

1° 

30' 

J0 

90" 

72// 

54" 

36" 

18" 

9" 

4" 

In  order,  therefore,  to  make  the  smallest  error  in  the  read- 
ing, the  half-shadow  must  be  chosen  as  small  as  possible. 
But  inasmuch  as  with  decreasing  half-shadow  the  total  illu- 
mination at  the  zero  point  decreases  also,  it  is  not  practicable 
to  go  below  a  certain  limiting  value  for  the  half-shadow,  which 
varies  with  the  intensity  of  the  source  of  light,  because  with  a 


METHODS   OF   OBSERVATION  341 

field  of  view  which  is  too  dark,  the  sensitiveness  of  the  eye 
in  recognizing  differences  in  illumination  decreases,  and  p,  in 
consequence,  grows  larger  and  with  it  A  (3.  For  a  given 
source  of  light  the  error  in  reading,  d  yff,  for  a  certain  value  of 
a,  reaches  a  minimum,  and  the  brighter  the  source  of  light 
the  smaller  may  a  be  to  give  it.  We  have  then  the  follow- 
ing rule  :  Let  the  source  of  light  be  chosen  as  bright  as  possible, 
and  the  half-shadow  as  small  as  possible,  but  at  least  so  large 
that  the  eye  may  make  the  required  reading  without  great  effort. 

108.  Methods  of  Observation. — We  are  concerned  here  with  the 
operations  which  the  observer  follows  in  order  to  secure  equal 
illumination  in  the  two  fields.  We  shall  discuss  but  a  few  of 
the  commonly  practiced  methods  which,  however,  when  prop- 
erly carried  out,  all  yield  good  results. 

If  one  moves  the  analyzer  rapidly  to  and  fro  past  the  zero 
point,  the  dividing  line  in  the  field  being  sharply  focused,  one 
has  an  impression  as  if  made  by  a  band  of  shadow  passing 
parallel  to  and  across  this  dividing  line  over  the  bright  field. 
Although  this  phenomenon  is  purely  subjective,  since  in 
reality  writh  proper  illumination  each  field  is  uniformly  bright, 
it  is  very  common  in  actual  practice  to  stop  in  the  motion  of 
the  analyzer  at  the  instant  in  which  this  shadow  appears  to 
glide  over  the  dividing  line.  However,  in  this  method  of 
observation  the  analyzer  is  checked  usually  a  little  too  soon  ; 
this  will  cause  no  error  only  when  the  mean  of  a  large  number 
of  trials  is  taken,  the  end  point  being  approached  alternately 
from  one  side  and  the  other.  But  the  hand  falls  easily  into  the 
habit,  after  turning  the  analyzer  to  and  fro,  of  stopping 
always  with  the  motion  from  the  same  side,  which  naturally 
introduces  a  systematic  error  into  the  observation. 

Another  plan  very  commonly  followed  is  this :  The 
analyzer  is  turned  several  times  rapidly  backward  and  forward 
until  the  differences  in  shade  on  the  two  fields  become  as 
nearly  as  possible  the  same,  and  then  the  fine  adjustment 
screw  is  turned  a  little,  at  random,  so  as  to  secure  as  accurately 
as  may  be  the  mean  position  between  the  end  positions  just 
reached.  This  method  is  naturally  applicable  only  when  the 
fine  screw  has  no  lost  motion,  but  gives  good  results  when  the 
contrasts  are  taken  sufficiently  small. 


342  POLARIZATION    APPARATUS 

A  third  method  of  final  adjustment  is  followed  by  Lippich1 
in  all  his  experiments.  The  analyzer  is  turned  at  first  rapidly 
and  then  slowly,  step  by  step,  and  always  in  the  same  direction, 
until  apparently  uniform  illumination  is  reached  ;  if  it  is  thought 
that  this  point  is  overreached,  the  analyzer  is  turned  back  and 
the  operation  repeated.  When  the  point  of  equal  illumination 
is  approached,  the  eye  is  opened  momentarily  only  at  each  step. 
Of  course,  one  does  not  reach  by  this  method  that  position  of 
the  analyzer  at  which  objectively  the  two  fields  have  the  same 
illumination,  but  a  position  which  differs  from  this  but  little, 
and  which  depends  on  the  degree  of  differentiation  sensitive- 
ness (about  i  per  cent.)  in  the  observer;  the  analyzer  is 
stopped  at  that  point  where  the  eye  is  no  longer  able  to  recog- 
nize a  difference  in  brightness.  In  order  to  find  the  real  point 
of  equality  in  illumination,  the  final  adjustment  must  be  made 
alternately  from  one  side  and  the  other,  and  the  mean  of  all 
the  readings  taken. 

It  should  be  made  a  rule  to  compare  the  fields  over  their 
whole  extent,  and  after  each  adjustment  to  turn  the  analyzer 
appreciably  away  from  the  zero  position  because,  otherwise, 
one  can  fall  into  the  habit  of  systematically  stopping  the 
adjustment  at  the  same  wrong  point  always,  and  thus  uncon- 
sciously securing  a  very  small  mean  adjustment  error,  which, 
in  reality,  may  be  exceeded  several  fold  by  the  true  error  in  the 
result.  Also  avoid,  as  far  as  possible,  trying  to  remember 
with  any  instrument  in  which  direction  the  fine  adjustment 
screw  must  be  turned  to  secure  larger  or  smaller  readings  on 
the  graduated  circle,  because  in  knowing  this,  the  observations 
may  be  arbitrarily  affected. 

109.  Jellett's  Polariscope.2 — In  the  descriptions  of  special  half- 
shadow  instruments,  beginning  with  this  paragraph,  only 
those  features  of  the  optical  arrangements  will  be  discussed 
which  concern  the  polarizing  mechanism,  because  the  other 
optical  parts  are  essentially  the  same  in  all  forms  of  apparatus. 
The  first  half-shadow  polariscope  was  made  by  Jellett  in  1860. 
Between  the  polarizing  and  analyzing  nicols,  and  close  to  the 
first,  he  introduced  a  prism  of  the  following  construction  :  A 

1  Lippich  :  Wiener  Sitzungsberichte,  II,  91,  1084  (1885)  ;  II,  105,  323  (1896). 

2  Jellett  :  Rep.  Brit.  Assoc.,  39,  13  (1860). 


POLARISCOPE  343 

long  Iceland  spar  rhombohedron,  which  is  converted  into  a 
right  prism  by  grinding  down  its  ends,  is  sawed  through 
lengthwise,  making  two  halves,  separated  by  a  plane  which 

makes  the  small  angle  —  with  the  plane  standing  perpen- 
dicularly to  its  principal  section.  These  halves  are  then  put 
together  in  reversed  position,  so  that  the  two  principal  sections 
no  longer  coincide  but  make  the  angle  a,  the  half-shadow, 
with  each  other.  This  prism  is  mounted  in  a  tube  which 
carries  diaphragms  writh  circular  openings  at  each  end,  so  that 
the  round  field  of  view  appears  to  be  divided  by  the  cut  into 
two  equal  parts.  The  polarizing  nicol  is  so  placed  that  its 
principal  section  bisects  either  the  obtuse  or  acute  angle  which 
the  two  principal  sections  of  the  rhombohedron  form  with 
each  other.  Light  entering  the  apparatus  is  first  linearly 
polarized  by  the  polarizing  nicol  and  then  passes  the  spar 
rhombohedron,  in  the  two  halves  of  which  the  principal  sec- 
tions are  slightly  inclined  to  each  other.  If  the  analyzer  be 
now  turned  so  that  its  principal  section  is  vertical  to  that  of 
the  polarizing  nicol,  the  halves  of  the  field  appear  uniformly 
shaded.  This  is  destroyed  by  inserting  an  active  substance, 
and  in  order  to  secure  the  uniform  shadow,  the  analyzer  must 
be  rotated  through  a  definite  angle,  which  is  equal  to  the  angle 
of  rotation  of  the  substance. 

The  Jellett  polarizing  arrangement  was  later  modified  in 
this  way  :  Before  cementing  together  the  two  sides  of  an 
ordinary  Xicol  prism,  one-half  is  split  perpendicularly  to  the 
principal  section,  a  wedge,  with  the  small  acute  angle  a,  cut 
out,  and  then  the  three  pieces  united  to  form  a  single  prism. 
The  cut  half,  in  which  the  principal  sections  again  form  the 
half-shadow  angle  a  with  each  other,  is  turned  toward  the 
analyzer  in  mounting  the  polarizer  in  the  apparatus.  Exactly 
the  same  phenomena  appear  here  as  in  the  above  case,  as 
indeed  the  light  which  passes  through  the  cement  layer  of  the 
polarizer  vibrates  still  in  a  single  plane  only.  This  Jellett 
twin  prism  is  often  called  the  Schmidt-Haensch  polarizer, 
because  this  firm  regularly  employs  it  in  the  construction  of 
their  simpler  polariscopes. 


344  POLARIZATION    APPARATUS 

1 10.  Cornu's  Polarizer.1 — This  has  considerable  resemblance 
to  the  Jellett  polarizer  just  described,  and  is  made  by  cutting 
an  ordinary  Nicol  prism  along  its  whole  length,  corresponding 
to  the  plane  of  the  shortest  diagonal,  into  two  halves,  then 

grinding  from  each  surface  a  small  amount,  -—  ,  and  cement- 
ing the  pieces  together  again.  This  makes  a  double  Nicol 
prism  which  has  two  principal  sections,  making  the  half- 
shadow  angle  ae  with  each  other.  From  this  polarizer  the 
extraordinary  rays  only  can  emerge  from  each  side,  and  we 
have  then  a  field  of  view,  the  two  parts  of  which  are  so 
arranged  that  the  direction  of  polarization  of  all  the  rays  in 
the  one  field  makes  the  small  angle  of  with  the  polarization 
direction  of  the  rays  in  the  other  field.  If  the  analyzer  be  then 
so  placed  that  its  principal  section  bisects  this  half-shadow 
angle  a,  then  the  field  of  view  will  appear  faintly,  but 
uniformly,  shaded. 

The  polarizers  of  Jellett  and  Cornu  have  the  advantage  that 
any  light,  compound  or  homogeneous,  may  be  employed,  but 
they  suffer,  on  the  other  hand,  from  the  great  drawback  that 
the  half-shadow  angle  is  a  fixed  one.  In  the  Laurent  polarizer 
to  be  now  described,  it  will  be  seen  that  the  reverse  is  the 
case  ;  it  possesses  a  variable  half-shadow,  but  in  each  single 
instance  may  be  used  for  a  definite  homogeneous  light  only. 

4..  Laurent"  s  Half  -  Shadow  Instrument'1 
in.  Description  of  the  Apparatus. — In  the  Laurent  instrument, 
illustrated  in  Fig.  39,  the  light  from  a  homogeneous  source 
passes  through  the  illumination  lens  first  and  then  the  polar- 
izing mechanism.  This  consists  of  the  polarizing  nicol  B, 
which  may  be  moved  by  means  of  a  connected  lever  through 
a  small  angle,  shown  on  an  arc  above,  and  then  firmly  clamped, 
and  a  thin  quartz  plate  D,  which  is  cut  parallel  to  the  optic 
axis  and  so  cemented  to  a  circular  diaphragm  that  it  covers 
half  the  opening.  At  the  other  end  of  the  apparatus  are 
found  the  analyzer  E  and  the  telescope  F.  This  latter  is 
attached  to  the  circular  disk  G,  and  may  be  rotated  with  it. 
For  this  purpose  a  bevel  geared  wheel  is  found  on  the  back 

1  Cornu:  Bull.  Soc.  Chim.,  [2],  14,  140  (1870) 
1  Dingler's  poly.  J.,  333,  608  (1877). 


PRINCIPLE    OF   THE    LAURENT    POLARIZER 


345 


side  of  the  disk,  which  works  into  a  small  pinion  attached  to 

0       0    SI  a    S          0 


H 


Fig-  39- 

the  button  H.     The  fixed  verniers  J,  may  be  read  by  means 
of  the  movable  magnifying  glasses  K. 

112.  Principle  of  the  Laurent  Polarizer.  —  The  quartz  plate  A 
(Fig.  40),  covering  half  of  the  polarizer  diaphragm,  must  have 
perfectly  parallel  sides  and  must  be 
ground  exactly  parallel  to  the  optical 
axis  B  C.  The  thickness  of  the  plate, 
dy  depends  on  the  wave-length,  A,  of 
the  homogeneous  light  which  is  em- 
ployed in  illumination.  This  thickness 
must  be  so  chosen  that  the  two  rays, 
one  polarized  parallel  to  the  axis  of  the 
plate  and  the  other  at  right  angles, 
which  are  produced  from  the  light 
reaching  the  plate,  show  on  exit  a  dif- 
ference in  path,  tf,  which  is  an  odd  multiple  of  half  the  wave- 
length. If  we  represent  the  ordinary  and  extraordinary  re- 
fractive indices  of  quartz  for  light  of  wave-length  A,  with  n0 
and  ne,  we  have  the  condition  : 

d  =  d  (ne  —  na)  =  (  2m  -f  i) — , 


Fig.  4°. 


346  POLARIZATION    APPARATUS 

where  m  is  any  whole  number.     From  this  follows  the  thick- 
ness of  the  plate, 

d  =  (2m  -f  i)—    /(  ne  —  »„). 

2  / 

As  the  apparatus  is  always  constructed  for  sodium  light,  A 
in  this  case  is  o. 0005893  mm.,  n0  =  1.5442,  ne  =  1.5533,  an^ 
the  minimum  thickness  (m  =  o)  0.0324  mm.  But  as  such  a 
plate  would  be  too  thin  for  practical  use  some  odd  multiple  of 
this  thickness  under  half  a  millimeter  is  taken.  Even  such 
quartz  plates  are  usually  supplied  with  a  plane  glass  plate  for 
support.  If  it  is  desired  to  make  a  test  to  determine  whether 
the  quartz  plate  has  the  proper  thickness  or  not,  the  following 
method  may  be  followed.  Two  Nicol  prisms  are  placed  in  series 
in  parallel  light  of  the  wave-length  for  which  the  plate  is  made, 
and  so  that  their  principal  sections  are  parallel  to  each  other. 
Between  these  the  quartz  plate  to  be  tested  is  placed  and 
vertically  to  the  rays.  If  now  the  plate  is  turned  in  its  own 
plane  until  its  optical  axis  makes  an  angle  of  45°  with  the 
principal  sections  of  the  prisms,  the  field  becomes  dark  if  the 
plate  has  actually  such  a  thickness  that  it  produces  a  difference 
in  path  of  an  odd  multiple  of  half  a  wave-length. 

Let  B  D  represent  the  plane  of  polarization  and  amplitude 
of  the  linearly  polarized  homogeneous  light  coming  from  the 


(V 


polarizer,  and  let  it  make  the  angle  C  B  D  =  -  with  the  opti- 
cal axis  B  C.  The  light  passing  the  right  half  of  the  polarizer 
diaphragm  is  then  linearly  polarized  in  the  direction  B  D.  In 
order  to  avoid  unnecessary  complication  in  what  follows,  it  will 
be  assumed  that  all  rays  reaching  the  quartz  plate  fall  upon 
it  perpendicularly,  which,  in  practice,  is  essentially  the  case. 
Then  each  ray  in  entering  the  quartz  plate  is  broken  up  into 
an  ordinary  and  an  extraordinary  ray,  whose  refractive  plane 
is  the  principal  section  ;  that  is,  the  plane  passing  through  the 
axis  B  C  and  vertical  to  the  plate.  According  to  §90,  this 
plane  is  at  the  same  time  the  plane  of  polarization  of  the  ordi- 
nary ray,  while  the  extraordinary  ray  is  polarized  vertically  to 
the  principal  section.  Accordingly,  a  ray  with  the  amplitude 
B  D  on  entering  the  plate  is  decomposed  into  the  components 
B  G  and  B  H,  if  E  F  is  perpendicular  to  B  C.  The  ordinary 
component  B  G  is  polarized  parallel  to  the  axis  of  the  plate 


PRINCIPLE   OF   THE   LAURENT   POLARIZER  347 

while  the  extraordinary  component  is  perpendicular  to  the 
axis.  Both  components  pass  through  the  plate  in  a  perfectly 
vertical  direction.  Now,  the  thickness  of  the  plate  is  so  taken 
that  the  rays  polarized  parallel  to  the  axis,  differ  in  path  by 
half  a  wave-length  from  those  polarized  perpendicularly  to  the 
axis,  or  in  other  words,  one  set  suffers  a  retardation  of  half  a 
vibration  as  compared  with  the  other.  We  can  assume  that 
at  the  moment  in  which  the  ray  B  D  reaches  the  plate,  and 
the  decomposition  into  the  components  B  G  and  B  H  takes 
place,  the  vibrations  of  these,  in  the  directions  toward  G  and 
H,  begin  simultaneously  at  B,  so  that  in  the  moment  in  which 
they  leave  the  plate,  the  one  component  is  half  a  vibration 
ahead  of  the  other.  Imagine  further,  that  in  this  moment 
the  vibrations  begin  again  at  B,  and  that  those  of  the  ordi- 
nary component,  say,  take  place  as  before  toward  G,  then 
the  vibrations  of  the  extraordinary  component  must  be  in  the 
direction  J,  opposite  from  H.  The  amplitude  B  J  is,  of  course, 
equal  to  B  H,  if  reflection  and  absorption  are  left  out  of  con- 
sideration. Therefore,  two  rays  polarized  perpendicularly  to 
each  other  leave  the  plate,  whose  planes  of  polarization  are 
the  same  as  within  the  plate,  but  which  differ  from  each  other 
in  path  by  half  a  wave-length.  At  the  analyzer,  both  rays  are 
brought  back  to  the  same  plane  of  polarization  and,  therefore, 
brought  into  condition  to  produce  interference.  But  as  the 
difference  in  path  of  the  two  rays  is  exactly  half  a  wave-length, 
or  an  odd  multiple  of  the  same,  the  final  result  remains  un- 
changed if  we  replace  the  two  rays  B  G  and  B  J  by  the  ray 
B  K,  whose  plane  of  polarization  and  amplitude  B  K,  makes 

the  small  angle  --  with    the  optical    axis  B   C.      The   light 

coming  through  the  plate  then  is  in  the  condition  of  linearly 
polarized  light,  whose  direction  of  polarization  with  reference 
to  the  principal  section  of  the  plate  is  symmetrical  with  the 
direction  of  polarization  of  the  light  coming  from  the  polarizer. 
Therefore,  the  field  of  view  is  made  up  of  two  parts  whose 
polarization  directions  are  symmetrical  with  reference  to  the 
axis  of  the  plate.  The  half-shadow  ex  is  equal  to  twice  the 
angle  which  the  optical  axis  of  the  plate  makes  with  the  plane 
perpendicular  to  the  principal  section  of  the  polarizer.  If  the 


348  POLARIZATION    APPARATUS 

analyzer  is  then  placed  so  that  its  principal  section  bisects  the 
half-shadow  angle,  that  is,  if  it  is  made  parallel  to  the  optical 
axis  of  the  quartz  plate,  the  field  will,  appear  uniformly  shaded 
as  explained  in  §  105. 

113.  Accuracy  of  the  Laurent  Apparatus. — For  the  method  of 
conducting  the  observations,  reference  is  made  to  §93  and  §97, 
and  in  regard  to  the  illumination,  it  may  be  again  remarked 
that  a  homogeneous  light  must  be  employed  in  which  the 
Laurent  plate  produces  a  path  difference  of  half  a  wave-length. 
Instrument  makers,  up  to  the  present  time,  have  constructed 
these  plates  for  a  sodium  light  only  ;  the  rotations  for  other 
rays  may  not  be  measured  with  these  apparatus,  which  is  a 
drawback  in  their  use. 

The  delicacy  of  the  Laurent  polarimeter  depends,  according 
to  §107,  on  the  half-shadow  angle  chosen.  This  is  variable 
at  will,  as  the  principal  section  of  the  movable  polarizer  may 
be  given  any  desired  position  with  respect  to  the  axis  of  the 
quartz  plate.  But  even  when  a  comparatively  weak  sodium 
light  (Bunsen  burner  with  salt  bead)  is  employed,  and  there- 
fore a  large  half-shadow  angle  of  about  8°  taken,  the  mean 
error  of  an  adjustment  amounts  to  about  ±  2  minutes  of  arc 
only  ;  with  a  brighter  source  of  light  and  smaller  angle  this 
may  be  reduced  to  below  one  minute. 

The  instrument  maker  Heele1  has  lately  attempted  to 
increase  this  delicacy  by  another  arrangement  of  the  field  of 
view.  Instead  of  fastening  the  Laurent  plate  in  the  diaphragm 

so  that  it  covers  one-half  of  the 
(IBB  ^T^fc  field,  he  gives  it  a  circular  form  and 
cements  it  to  the  center  of  a  larger 
circular  glass  plate.  The  field  of 
view  appears  then  as  shown  in  Fig.  41,  concentrically  divided. 

With  the  Laurent  apparatus  the  angle  of  rotation  may  be 
measured  easily  within  about  =b  20".  But  if  this  accuracy  is 
to  have  a  real  value  the  various  systematic  errors  made, 
depending  on  the  construction  of  the  apparatus,  can  not 
amount  to  more  than  a  few  seconds.  But  the  reverse  has 
already  been  demonstrated  by  Lippich,2  in  1890,  theoretically 

i  Hecle  :  (Berlin  O,  Gruner  Weg,  104)  Zeitschr.  fur  lustrum.,  16,  269. 
»  Lippich  :  Zur  Theorie  der  Halhschattenpolari meter,  Wien.  Sitzungsber,  11,99, 
695  (1890). 


ACCURACY  OF  THE  LAURENT  APPARATUS       349 

as  well  as  practically,  who  showed  that  in  general  the  Laurent 
apparatus  can  not  be  an  absolutely  exact  measuring  instrument. 
Although  Lippich,1  in  1892,  published  an  abstract  of  this 
paper,  omitting  the  mathematical  discussion,  it  seems  to  have 
attracted  but  little  notice,  since  recently  several  investigators2 
have  published  very  delicate  measurements  made  by  aid  of  the 
Laurent  apparatus.  It  may  be  in  order  then  to  recapitulate 
the  main  results  of  Lippich' s  experiments. 

We  shall  first  recall  the  conditions  which  must  be  complied 
with  in  order  that  the  light  which  leaves  the  Laurent  plate 
may  take  the  form  of  rays  perfectly  polarized  in  one  direction 
only,  and  see  in  how  far  these  conditions  may  be  fulfilled. 
The  first  condition  that  all  rays  reaching  the  plate  must  enter 
it  perpendicularly,  can  never  be  accurately  attained;  the  phase 
difference,  therefore,  produced  by  the  plate  is  a  function  of 
the  incident  light,  from  which  it  follows  that  this  difference 
for  all  rays  of  the  same  wave-length  can  not  be  exactly  half  a 
wave-length.  The  further  conditions  that  the  plate  must  be 
perfectly  plane  parallel,  that  it  must  be  ground  exactly  parallel 
to  the  optical  axis,  and  that,  above  all  else,  it  must  have 
exactly  the  right  thickness,  are  requirements  which  can  never 
be  found  satisfied  in  the  same  plate.  Besides  this,  it  must  be 
considered  as  a  piece  of  good  fortune  to  find  a  perfectly  homo- 
geneous quartz  plate.  In  spite  of  all  these  errors  it  is  true 
that  all  the  ordinary  and  extraordinary  component  rays  leaving 
the  plate  are  linearly  polarized,  but  the  planes  of  polarization 
of  all  the  ordinary  rays  taken  by  themselves,  and  the  planes 
of  polarization  of  the  extraordinary  rays  considered  among 
themselves,  no  longer  coincide,  and  the  path  differences  may 
then  vary  from  each  other  appreciably.  In  other  words  the 
light  emerging  from  the  plate  may  exhibit  all  forms  of  elliptic- 
ally  polarized  rays.  The  wliole  series  of  rays  are  then  brought 
back  by  the  analyzer  to  the  same  plane  of  polarization  where 
they  interfere.  If  it  is  further  recalled  that  the  Laurent 
instrument  is  always  constructed  for  sodium  light,  which  is  by 
no  means  perfectly  homogeneous  light,  the  possibility  must  be 

1  L,ippich  :  Ueber  die  Vergleichbarkeit  polarimetrischer  Messungen,  Ztschr.  fur 
Instrum.,  12,  333  (1892). 

-  Rodger  and  Watson  :  Phil.  Trans.  Condon,  186  A,  621  (1895)  ;  Ztschr.  phys. 
Chem.,  19,  323  (1896). 


350  POLARIZATION    APPARATUS 

admitted  that  because  of  the  consequent  variations  in  path 
difference  the  final  effect  of  interference  must  differ  from  one 
apparatus  to  another,  and  that  the  light  leaving  the  analyzer 
of  one  apparatus  must  have  a  composition  different  from  that 
leaving  the  analyzer  of  another.  If  the  rotation  dispersion  of 
the  active  substance,  whose  angle  of  rotation  is  being  measured, 
is  also  considered,  it  will  follow,  without  any  thing  further,  that 
the  observed  angle  of  rotation  may  differ  in  different  instru- 
ments. It  remains  to  show  that  these  differences  may  be  quite 
appreciable. 

As  we  shall  see  later,  the  light  in  the  Lippich  half-shadow 
instrument  remains  always  linear  and  polarized  in  the  same 
direction,  so  that  in  these  instruments  no  differences  should  be 
found  in  measuring  one  and  the  same  rotation.  Now  let  the 
same  constant  angle  of  rotation  be  found  in  a  Lippich  appa- 
ratus, then  in  several  Laurent  instruments,  one  after  the  other, 
the  same  constant  sodium  flame  being  used  in  all  cases.  Then 
the  readings  of  the  several  Laurent  instruments  will  show 
variable  results  compared  with  that  of  Lippich.  In  the  theo- 
retical part  of  his  paper  Lippich  shows  this.  The  difference 
between  the  angles  of  rotation  measured  by  a  Lippich  and 
Laurent  instrument  is  proportional  to  the  size  of  the  angle, 
and  the  proportional  factor  is  a  function  of  the  half-shadow  of 
the  Laurent  apparatus  and  the  construction  of  the  Laurent 
plate.  Therefore,  in  one  and  the  same  Laurent  instrument,  the 
observed  angle  of  rotation  will  vary  with  the  half-shadow. 
When  definite  numerical  values,  such  as  are  found  in  practice, 
are  substituted  in  his  equations,  differences  amounting  to 
db  1 60"  result  in  measuring  an  angle  of  rotation  of  about  22°. 
It  must  be  further  considered  that  Lippich,  in  his  calculations, 
assumed  all  the  above  conditions  fulfilled,  and  deals  here  with 
this  case  alone  that  the  Laurent  plate  can  have  the  right  thick- 
ness only  for  a  definite  wave-length  of  the  sodium  light.  In 
reality,  therefore,  still  greater  differences  might  appear. 

Experiments  made  by  Lippich  are  in  accord  with  his  theo- 
retical considerations.  A  quartz  plate  used  had  a  constant 
angle  of  rotation  of  about  24°.  The  sodium  light  used  was 
filtered  through  a  dichromate  solution  and  a  copper  chloride 
solution  of  known  strength,  so  that  color  differences  left  were 


HALF-SHADOW   POLARIMETER 


351 


extremely  minute.  From  a  number  of 
measurements  agreeing  well  among  them- 
selves, it  was  found  that  the  differences 
between  the  readings  of  a  Lippich  in- 
strument and  two  Laurent  instruments 
amounted  to  45"  and  82".  The  indica- 
tions of  different  Laurent  polatimeters, 
and  of  one  and  the  same  instrument  with 
different  degrees  of  shadow ,  can  vary  among 
themselves  and  with  the  Lippich  apparatus 
by  amounts  which  are  greatly  in  excess  of 
the  possible  and  admissible  errors  of  obser- 
vation. The  conclusion  is  warranted  that 
an  angle  of  rotation  measured  by  a  Lau- 
rent half-shadow  polarimeter  cannot  be 
depended  upon  as  correct  within  o.  2  per 
cent. 

5.  Lippich' s  Half -Shadow  Polarimeter.1 
114.  Instrument  with  Double  Field. — The 
polarizing  mechanism  of  Lippich  com- 
bines variability  of  the  half-shadow  with 
use  of  any  heterogeneous  or  homogene- 
ous light,  and  thus  satisfies  the  two  re- 
quirements which  should  be  met  in  the 
most  perfectly  constructed  half-shadow 
instruments.  The  construction  of  the 
Lippich  polarizer  is  extremely  simple.  In 
front  of  the  polarizing  nicol  A  (Fig.  42), 
there  is  a  second  small  nicol  B,  which  is 
turned  toward  the  analyzer  and  covers 
half  the  large  one ;  it  is,  therefore,  desig- 
nated as  the  half  prism.  It  is  so  adjusted 
that  the  sharp  edge  C,  shown  as  a  point 
in  the  figure,  lies  in  the  axial  plane  of  the 
apparatus  and  divides  the  round  polarizer 
diaphragm  D  into  two  halves.  The  tele- 

1  Ivippich  :  Xaturwissenschaftl.  Jahrbuch  "Lotos," 
new  series,  II,  1880;  Ztschr.  fur  Instrum.  a,  167;  Wien. 
Sitzungsber,  II,  91,  roSi;  Ztschr.  fur  Instrum.,  14,  326; 
Wien.  Sitzungsber.  II,  105,  317. 


M 


L 


K' 


352  POLARIZATION    APPARATUS 

scope  focuses  on  the  edge  C.  While  the  half  prism  is  fixed,  the 
large  prism  A,  in  order  to  change  the  half -shadow,  is  made 
movable  around  the  axis  of  the  tube.  The  principal  sections 
of  the  two  prisms  may  make  with  each  other  the  small  angle 
a.  Then  the  light  coming  from  A  and  passing  through  the 
free  half  of  the  field  of  view  is  polarized  vertically  to  the  prin- 
cipal section  of  the  prism  A.  The  other  part  of  the  light  from 
the  same  prism  is  decomposed  into  two  components  on  enter- 
ing B,  and  of  these,  only  the  rays  vertical  to  the  principal 
section  of  the  half -prism  are  able  to  pass  through.  The  light, 
then,  which  comes  through  the  covered  half  of  the  field  of 
view  is  polarized  vertically  to  the  principal  section  of  the  half- 
prism.  We  have,  in  consequence,  a  field  made  up  of  two 
halves  whose  diiections  of  polarization  make  the  small  angle 
01  with  each  other.  At  the  same  time,  the  light  of  each  half 
remains  linear  for  all  wave-lengths,  and  polarized  in  the  same 
direction,  so  that  the  Lippich  polarizer  must  be  considered  as  the 
most  perfect  of  all  half -shadow  constructions.  As  a  part  of  the 
light  reaching  the  half  prism  is  reflected,  absorbed,  and  extin- 
guished in  passage,  the  intensity  of  the  covered  half  of  the 
field  is  always  smaller  than  that  of  the  free  half.  In  the  zero- 
position,  therefore,  the  principal  section  of  the  analyzer  cannot 
exactly  bisect  the  half -shadow  angle,  but  must  make  with  the 
polarization  direction  of  the  whole  prism  a  smaller  angle  than 
with  the  polarization  direction  of  the  half -prism.  Consult 
§105  to  §108. 

The  half  prism  requires  a  special  construction  and  adjust- 
ment. It  cannot  be  made  simply  by  mounting  a  prism  with 
right  end  surfaces  so  that  one  side  surface  C  E  falls  along  the 
axis  of  the  apparatus,  because  in  that  case  the  cone  of  rays 
passing  in  the  neighborhood  of  C  E  would  be  partly  cut  off. 
If  F  is  the  circular  analyzer  diaphragm,  and  if  a  perfectly 
normal  passage  of  the  rays  is  provided  for,  according  to  §96, 
then  each  half  of  the  field  of  view  will  possess  uniform  bright- 
ness in  case  each  cone  of  rays  from  any  point  of  the  field  of 
view,  whose  base  is  the  analyzer  diaphragm  F,  if  followed 
back  to  the  prism  A,  is  found  to  undergo  no  partial  obstruction 
by  the  half-prism,  and  all  the  ray  cones  which  belong  to  points 
on  the  free  side  of  the  edge  C,  when  prolonged  backwards  do 


HALF-SHADOW    POLARIMETER  353 

not  fall  in  part  through  the  half-prism,  and  all  other  ray-cones 
which  belong  to  points  on  the  covered  side  traverse  the  half- 
prism  completely.  These  conditions  may  be  perfectly  fulfilled. 
Let  G  H  be  the  axis  of  the  instrument.  We  shall  consider 
first  a  point  in  the  field  on-  the  free  side,  and  very  close  to  C. 
Call  the  angle  J  C  H,  half  of  the  cone  J  C  K,  /?,  which  is  deter- 
mined by  the  analyzer  diaphragm  and  the  distance  of  the  latter 
from  the  polarizer  diaphragm,  since  sin  ft  =  J  K/2  C  J.  If 
now,  the  side  surface  C  E  of  the  half-prism  is  given  an  incli- 
nation to  the  axial  plane,  which  is  a  little  larger  than  @  by  the 
amount  #,  then  the  cone  of  light  J  C  K,  when  prolonged  back- 
wards, will  reach  the  prism  A  without  suffering  a  partial 
obstruction  by  the  half -prism.  This  naturally  holds  true  for 
all  the  cones  of  light  which  belong  oo  the  free  side  and  farther 
away  from  C.  If  the  surface  C  E  of  the  half -prism  is  polished, 
it  is  clear  that  all  rays  reaching  it  on  the  outside  from  A  will 
be  reflected  to  one  side  so  that  they  cannot  pass  through  the 
analyzer  diaphragm  J  K.  Consider  next  the  cones  of  light 
corresponding  to  the  side  of  the  field  covered  by  the  half- 
prism,  and  J  C  K  is  now  the  cone  belonging  to  a  point  on  this 
covered  side,  infinitely  near  to  C.  Followed  backwards  this, 
of  course,  passes  into  the  half-prism  and  will  pass  through  it 
without  being  partially  cut  off,  in  case  the  prism  is  so  constructed 
that  the  ray  K  C  is  bent  in  the  direction  C  L,  because  then  J  C, 
still  further  within  the  prism,  will  be  refracted,  say  to  M.  The 
half-prism  must  be  so  constructed  that  the  ray  C  L,  makes  still 
a  very  small  angle  f  with  the  surface  C  E.  In  order  to  secure 
this,  the  half-prism  cannot  have  perfectly  perpendicular  end 
surfaces,  but  the  angle  E  C  N  =  y  must  be  somewhat  larger 
than  90°.  A  simple  calculation  gives  the  value  y  —  90°  -f- 
4  ft  +  3  €  ~\-  2  tf,  when  e  and  ft  are  made  about  10'.  Accord- 
ing to  the  dimensions  of  the  apparatus,  y  must  be,  therefore, 
between  92°  and  94.°.  But  care  must  be  taken  to  have  the 
optic  axis  of  the  half-prism  stand  vertical  to  the  long  edge 
C  E,  and  at  the  same  time  parallel  with  or,  better,  vertical  to 
the  refractive  edges  E  and  N.  Now  as  regards  bundles  of 
rays  from  points  further  away  than  C,  it  is  seen  that  they  all 
make  smaller  angles  with  the  perpendicular  to  the  surface 
C  N  than  does  the  ray  K  C,  from  which  it  follows  that  all 
23 


354  POLARIZATION    APPARATUS 

these  rays  pass  the  half- prism  without  obstruction.  But  all 
other  rays  which  pass  within  the  angle  f ,  or  fall  on  the  inner 
polished  surface  of  C  E,  are  so  thrown  to  one  side  that  they 
cannot  reach  the  analyzer.  A  small  portion  of  the  surface 
E  O,  in  the  neighborhood  of  the  edge  E  ;  that  is,  the  part  E  L 
remains,  therefore,  quite  inactive,  so  that  any  lacking  sharp- 
ness of  this  edge  is  of  no  importance.  But  the  edge  Cmust  be  per- 
fectly sharp  and  free  from  faults.  In  this  way,  the  two  halves  of 
the  field  possess  perfectly  uniform  illumination  up  to  the  dividing 
line,  and  if  the  edge  C  is  made  with  a  proper  degree  of  accuracy, 
at  the  end  of  the  zero-point  adjustment  it  will  be  scarcely  visible  ; 
this  is  a  requirement  for  an  easy  and  accurate  reading. 

Unfortunately,  the  opticians  do  not  always  adjust  the  half- 
prism  in  the  manner  just  described,  so  that  in  the  zero-point 
reading,  the  edge  C  appears  as  a  thick  black  dividing  line  be- 
tween the  two  fields,  wrhich  interferes  very  materially  with  the 
accuracy  of  the  observation.  But  this  fault  may  be  in  part,  at 
least,  corrected  by  giving  the  diaphragm  placed  immediately 
in  front  of  the  source  of  light  a  rectangular  form,  its  longer 
sides  standing  perpendicular  to  C,  and  about  four  times  as 
large  as  would  appear  necessary  from  the  dimensions  of  the 
illuminating  lens  and  analyzer  diaphragm.  In  this  manner  a 
very  fine  dividing  line  is  secured  again,  but  toward  the  end  of 
the  adjustment  a  narrow,  somewhat  brighter,  space  appears 
parallel  to  C  between  the  two  fields  which,  however,  is  by  no 
means  as  annoying  as  the  sharp  black  dividing  line.  It  must 
be  again  said  that  in  a  properly  constructed  Lippich  polarizer, 
the  dividing  line  made  by  the  edge  C  may  be  caused  to  dis- 
appear completely  in  the  final  reading. 

In  regard  to  the  accuracy  of  the  Lippich  apparatus,  it  may 
be  remarked  that  with  a  sufficiently  bright  light,  and  a  half- 
shadow  angle  of  one  degree,  the  mean  error  of  a  reading  is 
about  ±115  seconds  of  arc  ;  but  the  adjustment  must  be  made 
from  both  sides  and  the  error  taken  as  the  variation  from  the 
mean  of  all  the  determinations. 

115.  Instruments  with  Triple  Field. — A  field  of  this  kind  may 
be  secured  by  placing  two  half-prisms  B  and  C  in  front  of  the 
large  polarizing  nicol  A,  in  symmetrical  position,  as  shown  dia- 
grammatically  in  Fig.  43.  The  sharp  edges  E  and  F,  which  are 


INSTRUMENTS   WITH   TRIPLE    FIELD 


355 


brought  into  focus  by  the  reading  telescope,  divide  the  circular 

field  made  by  the  polarizer  diaphragm  D  into  three  fields,  H,  J, 

and  K.     The  width  of  the  middle  field  J  must  not  be  made  too 

large,  in  order  that  the  two  dividing  lines 

may  be  easily  seen  at  the  same  time.     With 

a  field  of  view  not  too  large,  the  middle  field 

is  chosen  so  as  to  have  the  areas  of  the  three 

fields  about  equal.     What  was  said  in  the 

last  paragraph  about  the  construction  and 

adjustment  of  the  half- prism  holds  strictly 

here  also. 

If  the  principal  sections  of  the  two  half- 
prisms  are  accurately  parallel,  and  if  they 
make  the  half-shadow  angle  a  with  the  prin- 
cipal section  of  the  Nicol  A,  which  is  mova-  J  I/ 
ble  around  its  axis,  then  when  the  analyzer  ' — 
is  turned  so  that  the  two  fields  H  and  J 
have  the  same  brightness,  the  field  K  must 
be  equally  bright,  in  case  the  two  half- prisms 
are  of  the  same  construction.  But  above 
everything  else,  it  is  important  that  the  two 
side  prisms  should  have  the  same  extinguishing  power  ;  this  may 
be  most  readily  tested  by  employing  an  intense  light  and  turn- 
ing the  analyzer  to  the  position  of  greatest  darkness  with 
reference  to  the  side  fields.  The  prism  A  is  then  turned  to 
make  the  middle  field  as  dark  as  possible  ;  in  this  situation, 
any  inequality  in  the  side  prisms  may  be  most  readily  recog- 
nized. 

The  advantage  in  this  arrangement  in  which  equal  illumi- 
nation is  secured  in  three  fields  over  that  with  two  fields,  con- 
sists in  this  increase  in  the  fields  in  which  comparison  of 
brightness  may  be  made,  and  is  favorable  as  long  as  the 
dimensions  of  the  individual  fields  are  not  too  small. 

This  fact  should  be  especially  mentioned  that  the  principal 
sections  of  the  two  side  prisms  need  not  be  exactly  parallel 
with  each  other;  indeed  the  following  considerations  will  show 
that  a  little  distortion  of  the  position  of  one  with  reference 
to  the  other  increases  the  sensitiveness  of  the  readings.  First 
let  us  imagine  the  half  prisms  exactly  parallel,  and  the  analyzer 


Fig.  43 


356  POLARIZATION    APPARATUS 

in  that  position  in  which  the  three  fields,  objectively  considered, 
have  the  same  brightness,  then  it  will  be  necessary  to  turn  the 
analyzer  to  the  right  and  left  through  a  certain  small  angle  ft, 
dependent  on  the  half- shadow  angle  ar,  in  order  to  just  see  a 
distinction  between  the  middle  fields  and  the  side  fields.  2  ft 
is  then  the  measure  of  the  uncertainty  of  adjustment  with  this 
arrangement ;  of  course,  leaving  the  increase  of  fields  out  of  con- 
sideration, the  interval  of  uncertainty  with  the  double  field 
may  be  taken  as  2  ft  also.  But  if  we  turn  one  of  the  half- 
prisms  by  the  amount  of  the  angle  ft  from  its  parallel  position, 
by  which  the  half-shadow  angle  a  for  the  turned  prism  is  not 
sensibly  changed,  because  of  the  smallness  of  ft  (see  §107), 
then  the  conditions  become  different.  In  the  neighborhood  of 
the  zero  position  of  the  analyzer,  in  which  all  three  fields  have 
nearly  the  same  brightness,  a  difference  between  the  side 
fields  H  and  K  will  be  always  just  noticeable.  If  now  we  give 
the  analyzer  such  a  position  that  objectively,  for  example,  the 
middle  field  J  has  the  same  brightness  as  H,  and  in  which,  in 
consequence,  a  difference  between  J  and  K  is  just  distinguish- 
able, then  the  rotation  of  the  analyzer  through  the  angle 
ft,  in  a  certain  direction,  is  sufficient  to  make  a  difference 
between  J  and  H  just  apparent.  The  interval  of  uncertainty 
in  the  adjustment  is  now/?;  that  is,  just  half  as  great  as 
before.  If  we  take  as  the  limiting  value  for  this  uncertainty 
in  delicacy p  =  i  per  cent.,  the  angle  ft  which  the  principal 
sections  of  the  two  side  prisms  must  make  with  each  other  in 
order  to  secure  the  maximum  of  delicacy  is  given,  according 

to  §107,  by  the  formula,  ft  =  515  tan  — -,  in  seconds  of  arc. 

The  polarizer  must  be,  therefore,  so  constructed,  that  all 
necessary  movements  of  the  prisms  may  be  made  after  they 
are  placed  in  the  apparatus.  Inasmuch  as  double  the  accuracy 
may  be  secured  with  the  triple  field  as  is  possible  with  the 
double  field,  as  indeed  Lippich  has  shown  by  observations, 
the  polarizer  with  triple  field  has  already  come  into  general 
use. 

116.  Instrument  According  to   Lummer   with  Quadruple  Field.1— 
In  this,  it  is  not  the  uniform  brightness  of  different  fields,  but 

Ztschr.  fur  lustrum .,  16,  209(1896). 


INSTRUMENT  WITH  QUADRUPLE  FIELD 


357 


the  equally  strong  appearance  of  tivo  fields  on  a  uniform  back- 
ground which  is  taken  for  comparison.  With  this  arrange- 
ment the  fields  are  so  polarized  that  on  turning  the  analyzer  in 
one  direction  from  the  zero-position,  the  one  field  of  contrast 
becomes  brighter  in  comparison  with  its  background,  in  pro- 
portion as  the  other  becomes  darker.  In 
order  to  secure  these  relations,  four  polari- 
zation prisms  must  be  used,  so  that  four 
fields  result.  In  front  of  the  large  polar- 
izing nicol  A,  as  shown  in  Fig.  44,  there  is, 
first,  the  moderately  large  half-prism  B,  and 
then  in  front  of  this,  the  two  smaller  half- 
prisms  C  and  D  in  symmetrical  adjustment. 
The  field  of  view  F,  bounded  by  the  round 
polarizer  diaphragm  opening  E,  appears 
then  divided  by  the  sharp  edges  of  the  half 
prisms  into  the  four  fields  G,  H,  J,  and  K. 
After  the  prisms  A  and  B  are  given  such  a 
position  that  their  principal  sections  make 
the  half-shadow  angle  a  with  each  other,  the 
analyzer  is  turned  until  the  two  fields  H 
and  J  have  the  same  illumination.  Then  the 
two  half -prisms  C  and  D  are  adjusted  with 
their  principal  sections  turned  so  that  the  E  ^- 
fields  G  and  K  differ  to  the  same  extent  in 
brightness  from  the  two  middle  fields  ;  that 
is,  until  these  side  fields  are  either  lighter 
or  darker  than  the  middle  fields,  and  in  the 
same  degree.  The  accuracy  of  the  adjust- 
ment is  greatest  when  the  contrast  is  chosen 
as  about  4  per  cent.  On  now  turning  the  analyzer  from  its  zero 
position,  that  change  follows  which  is  peculiar  to  the  contrast 
principle  ;  while  the  two  middle  fields  become  unequally  bright, 
the  contrast  between  the  fields  G  and  H  is  diminished  in  the 
same  degree  in  which  that  between  J  and  K  is  increased,  or  vice 
versa.  As,  however,  the  telescope  cannot  be  focused  on  the 
three  edges,  sharply,  at  the  same  time  it  is  best  not  to  depend 
on  the  help  which  a  comparison  of  the  two  middle  fields  would 
afford,  but  to  focus  on  the  sharp  edges  of  the  two  side  prisms 


Fig.  44. 


358  POLARIZATION    APPARATUS 

C  and  D.  Any  lack  of  sharpness  in  the  middle  line  is  then  of 
no  importance,  as  in  the  neighborhood  of  the  zero  position  of 
the  analyzer,  the  two  middle  fields  have  the  same  brightness. 
But  up  to  the  present  time  fuller  results  as  to  the  practical 
working  of  this  somewhat  complicated  contrast  polarizer  are 
lacking. 

6.  Mechanical  Constructions  of  the  Lippich  Polarization 

Apparatus 

117.  Landolt's  Apparatus.1 — In  order  to  avoid  repetitions,  it 
may  be  recalled  that  the  part  of  the  apparatus  turned  toward  the 
source  of  light  contains,  always,  the  illumination  lens  and  the 


Fig-  45- 

Lippich  polarizer  with  double  or  triple  field,  while  at  the  other 
end  of  the  instrument  are  found  the  analyzer,  the  telescope, 
and  the  graduated  circle.  Landolt  has  given  the  Lippich 
apparatus  a  form,  making  it  suitable  for  use  in  chemical  labo- 
ratories, so  that  not  only  may  tubes  be  examined  in  it,  but 
vessels  of  any  shape  may  be  inserted  between  polarizer  and 
analyzer.  This  instrument  is  illustrated  in  Fig.  45  and  con- 
sists of  a  strong  iron  bar,  a,  on  one  end  of  which  are  attached 
the  analyzer,  turned  by  the  lever  c,  the  graduated  circle  b, 
and  reading  microscopes  (for  reading  to  0.01°),  while  at  the 

1  I<andolt :  "Uebcr  eine  veranderte  Form  des  Polarisationsapparates  fur  chemische 
Zwecke."  Her  d.  chem.  Ges..,  28,  3102.  The  instruments  are  made  by  Schmidt  and 
Haensch,  Berlin. 


LANDOLT'S  APPARATUS  359 

other  end  there  is  the  polarizer  d,  whose  movable  prism  may 
be  adjusted  to  change  the  half -shadow  angle  by  means  of  the 
lever  e.  The  whole  combination  may  be  attached  to  a  strong 
Bunsen  stand  and  clamped  fast.  The  guide  sleeve  is  furnished 
with  a  thread  below,  and  the  nut  g,  by  which  means  a 
horizontal  arm  holding  at  its  ends  two  prismatic  carriers  f  f 
may  be  moved  up  or  down.  Two  small  steel  rods  dropped 
from  the  bar  a  provide  for  perfectly  vertical  motion.  The 
trough  h  which  is  intended  to  hold  polarization  tubes  may  be 
attached  to  the  carriers  f  f  and  moved  up  or  down  until  the 
tube  is  brought  into  the  axis  of  the  apparatus  ;  the  final  verti- 
cal adjustment  is  accomplished  by  aid  of  the  screw  at  g  ;  the 
trough  h  is  also  slightly  movable  on  its  bed  plate,  through  a 
small  angle.  Besides  this,  a  brass 
plate  i  may  be  placed  on  the  car- 
riers instead  of  the  trough,  and 
this  serves  to  carry  vessels  of 
glass.  For  the  investigation  of 
substances  in  strongly  heated 
or  molten  condition,  or  for  the 
application  of  very  low  temper- 
atures, the  arrangement  in  Fig. 
46  may  be  used.  This  is  a  rec- 
tangular brass  box,  through 
which  a  gold  plated  brass  tube 

passes,  the  projecting  ends  of  which  may  be  closed  by  glass 
plates  and  screw  caps.  A  narrow  tube  which  is  soldered  to 
this  observation  tube,  and  which  passes  through  the  movable 
top  of  the  box  provides  for  the  expansion  or  contraction  of  the 
active  substance  filled  into  it.  Besides  this  there  are  openings 
in  the  cover  for  a  thermometer  and  stirrer.  If  the  box  is  filled 
with  some  substance  suitable  for  a  bath,  and  heated  by  means 
of  a  lamp  placed  beneath,  it  is  possible  to  study  the  rotating 
power  of  bodies  at  any  desired  high  temperature  ;  it  is  advisable 
to  cover  the  box  with  a  protecting  layer  of  asbestos  and  put  up 
screens  to  protect  other  parts  of  the  apparatus  as  far  as  possible 
from  the  high  temperature.  If  the  box  is  filled  with  a  freezing 
mixture  for  investigations  at  a  low  temperature,  it  is  neces- 
sary to  attach  glass  cylinders,  furnished  at  the  ends  with  plane 


POLARIZATION    APPARATUS 

glass  plates,  to  the  screw  caps  and  put  in  these  a  little  calcium 
chloride  to  prevent  precipitation  of  moisture. 

118.  Apparatus  with  Adjustable  Length.1 — In  many  investiga- 
tions it  is  an  advantage  to  be  able  to  change  the  distance  be- 
tween polarizer  and  analyzer  at  will.  Fig.  47  illustrates  the 


Fig-  47- 

construction  of  apparatus  in  which  this  is  possible,  the  sup- 
porting parts  being  made  intentionally  heavy.  In  this  the 
carriers  of  the  optical  parts  A,  B  and  C  may  be  moved  along  a 
strong  cast-iron  optical  bench  D  and  clamped  fast  by  the 
screws  E  in  any  desired  position.  Then  motion  in  a  vertical 
direction  is  made  possible  by  the  rack  and  pinion  mechanism  at 
F  and  the  set  screws  G.  C  supports  a  glass  trough  made  to 

1  From  Schmidt  and  Haen*ch,  Berlin. 


APPARATUS  FOR  EXACT  MEASUREMENTS 


361 


contain  solutions  for  the  purification  of  the  light,  B  the  illu- 
minating lens,  and  the  Lippich  polarizer,  A  the  analyzer,  the 
telescope,  and  the  graduated  circle.  Here,  also,  any  desired 
vessels  may  be  inserted  between  the  polarizer  and  analyzer.  In 
the  figure,  a  heating  vessel  and  air-bath  are  shown,  which,  in 
some  points,  are  different  from  the  construction  described  in 
the  last  paragraph.  The  box  H,  of  brass,  serves  as  an  air-bath, 
and  has  at  the  sides  two  projecting  tubes  J  with  glass  caps. 
The  cell  to  hold  the  substance  to  be  investigated,  K,  is  shown 
in  the  figure  on  top  of  the  air-bath  H.  At  the  time  of  ex- 
periment, this  is  brought  down  into  H,  and  in  central  adjust- 
ment on  a  little  table  at  the  bottom  of  H.  The  cell  K  is  made 
of  brass  and  nickel  plated  ;  but  the  two  ends  through  which 
the  polarized  light  must  pass  are  made  of  parallel  glass  plates. 
The  screw  cover  of  the  cell,  and  corresponding  to  this  the  cover 
of  the  air-bath  H  contains  two  holes  through  one  of  which  in 
each  case  the  little  tube  L  passes,  which  permits  the  expansion 
of  the  substance  during  warming,  while  through  the  other 
openings,  the  thermometer  M  may  be  introduced  into  the  cell 
K. 

119.  Apparatus  for  Especially  Exact  Measurements-1— The  large 


Fig.  48. 

apparatus  shown  in  Fig.  48  permits   a  very  accurate  reading 

1  From  Schmidt  and  Haensch.  Berlin. 


362 


POLARIZATION   APPARATUS 


of  the  graduated  circle.  Two  strong  cast  iron  carriers,  A  and 
B,  each  of  which  ends  in  two  legs,  are  attached  in  vertical  posi- 
tion by  aid  of  three  horizontal,  nickel  plated  brass  rods  C,  and 
with  these  constitute  a  heavy  solid  stand.  This  is  screwed  down 
to  a  thick  wooden  base  through  the  four  legs ;  of  the  two  car- 
riers one,  A,  serves  to  hold  the  illuminating  lens  and  the  Lip- 
pich  polarizer;  the  other,  B,  supports  the  analyzer,  the  gradu- 
ated circle,  and  the  telescope.  For  protection  of  the  gradu- 
ation, the  circle  is  covered  with  the  case  D,  which  has  two 
mica  covered  openings  in  the  neighborhood  of  the  twro  read- 
ing telescopes  E.  By  aid  of  the  four  arms  F,  the 
graduated  circle  may  be  rotated  on  its  axis  ;  it 
may  be  fastened  by  the  clamp  screw  G,  and  then 
the  more  delicate  motion  may  be  accomplished 
by  aid  of  the  lever  H,  the  lower  end  of  which 
rests  against  a  point  attached  to  a  spiral  spring  J 
on  one  side,  and  on  the  other,  against  the  microm- 
eter screw  K.  With  this  construction,  it  is  pos- 
sible to  move  the  circle  and  the  attached  analyzer 
rapidly  to  and  fro  across  the  zero  position  without 
any  lost  motion,  which  is  very  advantageous  for 
the  observation.  The  illumination  of  the  circle 
is  provided  for  by  the  two  gas-lamps  L  (only  one 
is  shown  in  the  figure),  the  light  from  which  is 
reflected  on  the  circle  by  aid  of  the  bent  glass 
rods  M  which  are  blackened  on  the  outside,  while 
at  the  same  time  the  movable  glass  arm  N  illu- 
minates the  notebook  of  the  observer,  and  one  of  the  two  mi- 
crometer screw-heads  O.  The  light  from  Nmay  be  shut  off  by 
turning  the  black  screen  P.  The  illumination  may  be  still  more 
easily  accomplished  by  aid  of  small  incandescent  lamps  attached 
in  the  right  positions.  On  looking  through  one  of  the  reading 
telescopes  E  in  making  the  observation,  an  image  such  as  is  illus- 
trated in  Fig  49  is  seen.  The  two  parallel  threads  running 
through  the  field  between  the  marks  198  and  199  serve  as  an  in- 
dex. These  threads  may  be  moved  in  a  vertical  direction  by  aid 
of  the  screw-head  O.  To  count  the  revolutions,  the  micrometer 
is  furnished  with  a  counting  scale  in  focus  of  the  ocular;  the  mo- 
tion from  tooth  to  tooth  corresponds  to  a  complete  revolution  of 


Fig-  49- 


APPARATUS    FOR    EXACT    MEASUREMENTS  363 

the  head.  One  point  on  the  scale  is  distinguished  by  a  deeper 
indentation,  and  from  this  the  rotations  of  the  screw-head  made 
are  counted.  One  full  revolution  of  the  screw-head  corresponds 
to  half  the  interval  between  the  two  division  marks  on  the 
graduated  circle,  that  is  to  o.  i°.  Now,  as  the  head  is  divided 
into  50  parts,  one  of  these  must  equal  0.002.  The  threads  are 
to  be  so  adjusted  that  they  pass  through  the  deep  indentation 
of  the  counting  scale  when  the  index  of  the  screw-head  is  at 
the  zero  point  on  the  screw-head  graduation.  This  is  the 
fixed  zero  position  of  the  threads  from  which  the  observed 
rotation  is  estimated  ;  in  the  figure  the  threads  are  shown  a 
little  away  from  this  zero  position.  The  reading,  in  the  case 
illustrated  by  the  figure,  would  be  made  in  this  way:  198.7° 
is  first  read.  Then  by  turning  the  screw,  the  threads  are 
brought  into  such  a  position  that  they  include  the  division 
198.6°  centered  between  them.  In  the  illustration  it  will  be 
necessary  to  give  the  screw-head  over  one  complete  revolution 
to  accomplish  this.  If  the  figures  on  the  head  graduation 
run  so  that  larger  numbers  are  passed  in  doing  this  and,  if 
finally,  the  index  stands  at  36.5,  then  36.5  X  0.002°  must  be 
added  to  the  first  reading  of  198.7°  ;  that  is,  the  complete  read- 
ing is  198.773°.  In  these  instruments,  the  large  circle  is 
usually  divided  into  400°,  from  which  it  follows  that  the 
figures  so  read  off,  must  be  multiplied  by  0.9  to  obtain  the 
true  degrees  of  arc.1  As  it  is  not  difficult  to  read  0.0009° 
in  this  manner,  and  as  the  mean  error  of  reading  an  adjustment 
is  about  ±  0.0005°,  it  must  be  determined  whether  or  not  the 
errors  due  to  lost  motion  along  with  periodic  and  continuous 
errors  in  the  screw  are  all  below  0.0005°,  if  one  is  to  be  cer- 
tain of  introducing  no  systematic  errors  in  the  final  result. 
Two  complete  micrometer  screw-head  revolutions  must  corre- 
spond with  the  same  degree  of  accuracy  to  the  interval  be- 
tween any  two  divisions  on  the  graduated  circle.  That  such 
an  accurate  reading  is  not  illusory,  will  be  admitted  when  it  is 
remembered  that  under  favorable  conditions  the  mean  error  of 
an  adjustment  is  less  than  ±  0.002°. 

The  apparatus  shown  in  Fig.   48  is  suitable  also  for  the 

1  As  no  great  amount  of  work  is  required  for  this  multiplication,  it  must  be  con- 
sidered as  inexcusable  in  scientific  publications  to  report  figures  for  a  periphery  of 
400*,  because  in  this  way,  lasting  errors  will  be  introduced  into  the  literature. 


364  POLARIZATION   APPARATUS 

investigation  of  electro-magnetic  rotations.  The  spools  to 
hold  the  copper  wire  coils  and  observation  tubes  are  carried  on 
sliders  which  work  on  the  two  brass  rails  Q,  so  that  they  may 
be  easily  shunted  in  or  out  of  the  field  as  desired. 

120.  Allowance  for  the  Earth's  Magnetism.  —  As  the  large  appa- 
ratus just  described  may  be  used  in  very  exact  determinations, 
this  is  the  proper  place  to  add  a  few  remarks  on  the  extent  of 
the  influence  of  the  earth's  magnetism  in  the  measurement  of 
an  angle  of  rotation.  The  amount  of  the  electro-magnetic 
rotation  of  the  plane  of  polarization  depends  on  the  substance, 
and  is  proportional  to  the  length  of  layer  and  to  the  intensity 
of  the  electric  or  magnetic  field  component  parallel  to  the 
direction  of  the  light  rays.  Most  substances  possess  a  positive 
magnetic  rotating  power  ;  that  is,  they  turn  the  plane  of  polari- 
zation in  the  same  direction  in  which  the  galvanic  current 
which  may  be  considered  as  producing  the  magnetic  field 
flows.  Therefore,  in  considering  the  influence  of  the  earth's 
magnetism,  as  the  light  rays  always  pass  horizontally  through 
the  apparatus,  we  are  concerned  only  with  the  horizontal  com- 
ponent of  the  earth's  magnetism, 


If  then  the  effect  of  the  earth's  magnetism  is  to  be  wholly 
avoided,  the  axis  of  the  apparatus  should  be  placed  perpen- 
dicularly to  the  magnetic  meridian.  If  the  axis  lies  in  this 
meridian,  the  effect  of  the  earth's  magnetism  on  the  rotation, 
q>,  reaches  a  maximum.  If,  besides  this,  the  light  rays  pass 
in  the  meridian  from  north  to  south,  the  rotation  of  the  plane 
of  polarization  is  in  the  negative  direction.  In  order  to  give 
an  idea  of  the  maximum  value  of  the  magnetic  rotation,  <p, 
the  following  figures  for  sodium  light  are  sufficient  :  for  a 
quartz  plate,  i  mm.  thick,  ground  perpendicularly  to  the  axis 
*p  =  0.021".  In  quartz  investigations,  therefore,  the  influence 
of  the  earth's  magnetism  is  of  no  moment.  But  the  case  is 
different  with  tubes  of  liquids.  If  the  tube  contains  pure 
water,  this  and  the  end  plates  also  rotate  the  plane  of  polari- 
zation. While  the  effect  of  the  latter  is  always  very  small, 
since  fora  plate  of  glass  i  mm.  in  thickness,  </>  is  0.049",  the 
rotation  of  a  column  of  water,  20  cm.  in  length,  is  cp  =  3.0"; 


SUMMER'S  HALF-SHADOW  INSTRUMENT 


365 


that  is  an  amount  which  must  be  taken  into  consideration  in 
exact  investigations,  certainly  at  least  in  the  calculation  of 
errors.  It  is  always  best  to  place  the  axis  of  the  apparatus 
perpendicular  to  the  magnetic  meridian  so  as  to  wholly  elimi- 
nate the  magnetic  effect.  It  may  be  remarked  in  conclusion, 
that  the  magnetic  rotation  in  gases  and  vapors  may  be  wholly 
neglected. 

7.  Lummer*  s  Half -Shadow  Apparatus' 

121.  Description  and  Theory  of  the  Instrument. — As    it    has  not 
yet  been  fully  described,  the  illustra- 
tion in  Fig.  50  is  only  diagrammatic,  A 
and  the  discussion  will  be  brief.     The  I  j 
hypothenuse  surface  A  B,  of  a  right  ^ 
angled  glass  prism  ABC,  as  free  as 
possible  from  any  strain,  is  silvered 
and  a  part  of  the  silver  layer  removed. 
Care  is  taken  to  have  the  two  fields  join  each 
other  with  perfectly  sharp  edges,  and  that  they 
have  a  position   perpendicular  to  the  refractive 
edge  of  the  prism.     The  illuminating  lens  D  is 
placed  in  front  of  one  of  the  side  surfaces  of  the 
prism  A  C,  and  between  them  the  polarizing  Nicol 
E,  so  that  the  light  rays  suffer  total  reflection  on 
the   hypothenuse  surface  A  B.     The  analyzer  F 
and  the  telescope  G  H  J  face  the  other  cathetus 
surface  B  C,   and  the  two  hypothenuse  fields  are 
brought  into  focus.     Imagine  the  polarizer  placed 
at  first  so  that  its  principal  section  is  vertical  to  the 
plane  of  reflection  ;  that  is,   so   that  the  plane  of 
polarization  forms  zero  angle  with  the  plane  of 
reflection,  then  the  light  reflected  from  the  glass 
and  silver  surfaces,  and  passing  through  B  C  is 
rectilinearly  polarized  and  in  the  plane  of  reflec- 
tion.    The  two  fields  appear  uniformly  light  or 
dark  with  any  position  of  the  analyzer  F.    But  if 
the  plane  of  polarization  of  the  polarizer  E  be 

a 

turned  through  the  angle  —  away  from  the  position  parallel  to 

Ztschr.  fur  Instrum.  15,  293  (1895). 


L<=>J 

Fig.  50. 


366  SACCHARIMETERS 

the  plane  of  reflection,  then  the  planes  of  polarization  of  the 
light  reflected  from  the  glass  and  silver  surfaces,  are  sym- 
metrical to  the  plane  of  reflection  and  the  two  fields  be- 
have as  half-shadow  fields,  whose  half-shadow  is  equal  to  a. 
Of  course,  a  division  into  three  or  any  number  of  parts  may 
be  made  in  the  simplest  manner  in  the  field  of  view.  But 
it  is  difficult  to  secure  a  glass  prism  perfectly  free  from  dis- 
tortion strains,  and  to  prevent  such  from  appearing  during  an 
observation.  There  are  noticed,  therefore,  even  with  small 
half-shadows,  brighter  or  darker  parts  in  the  field  of  view. 
Further,  the  light  leaving  the  prism  is  not  absolutely  linearly 
polarized,  but  also  elliptically,  and  this  the  more  strongly,  the 
larger  the  half-shadow.  For  the  reasons  mentioned  in  §113, 
the  apparatus  should  not,  therefore,  be  used  in  exact  measure- 
ments. 

b.  Saccharimeters 

122.  Simple  Wedge-Compensation. — The  saccharimeters  largely 
used  in  practice,  serve  especially  for  the  determination  of  the 
strength  of  sugar  solutions.  Such  a  determination  may  be 
made  with  any  of  the  instruments  described  above,  but  they 
require  homogeneous  light  ;  to  be  able  to  use  ordinary  white 
light  in  practical  work  was  the  leading  factor  which  led  to 
the  construction  of  the  saccharimeters.  This  problem  was 
solved  in  1848  by  the  wedge-compensation  of  Soleil,  which  is 
the  characteristic  part  in  all  saccharimeters.  This  will,  there- 
fore, be  described  first,  but  it  may  be  remarked  that  a  full 
discussion  of  the  theory  of  wedge-compensation  would  lead  too 
far  here,  and  it  must  be  left  for  a  special  treatment. 

As  already  explained,  quartz  plates  cut  perpendicularly  to 
the  axis  rotate  the  plane  of  polarized  light,  and  rather  strongly, 
since  a  plate  I  mm.  in  thickness  turns  the  plane  of  sodium 
light  about  ±  21.72°.  In  order  to  simplify  the  following  con- 
siderations we  shall  assume  any  of  the  polarization  instruments 
as  illuminated  by  homogeneous  light.  We  place  the  analyzer 
in  the  zero  position,  or  as  we  may  briefly  express  it  with  Fric, 
in  the  position  of  optical  equilibrium.  Then  bring  between  the 
polarizer  and  analyzer  any  positively  or  negatively  rotating 
substance  and  the  optical  equilibrium  will  be  destroyed,  which 
may  be  restored  again,  without  turning  the  analyzer  by  adding, 


SIMPLE   WEDGE-COMPENSATION 


367 


also  between  polarizer  and  analyzer,  a  negative  or  positive 
quartz  plate  of  such  thickness  that  the  algebraic  sum  of  the 
rotations  of  the  active  body  and  the  quartz  is  equal  to  zero. 
It  is  then  said  that  the  rotation  of  the  body  is  compensated  by 
the  opposite  rotation  of  the  quartz.  The  Soleil  wedge-compen- 
sation is  nothing  but  such  a  quartz  plate,  whose  thickness, 
within  certain  limits,  may  be  changed  so  L 
as  to  compensate  any  desired  rotation 
within  limits.  Of  two  equally  thick, 
plane  parallel  quartz  plates,  cut  perpen-  l 
dicularly  to  the  axis,  the  negative  one 
A  B  C  D  and  the  positive  one  E  F  G  H, 
Fig.  51,  imagine  one,  say  the  latter,  divi- 
ded by  a  cut,  vertical  to  the  plane  of  the 
paper,  into  the  two  wedges,  E  J  K  H  and 
J  F  G  K,  and  that  the  last  is  enlarged  to 
form  the  wedge  L  M  N.  The  large  and 
the  small  wedge  have  now  the  same 
wedge-angle.  The  whole  wedge-compen- 
sation is  situated  between  the  polarizer 
and  analyzer,  so  that  the  light  rays  pass 
in  and  out  from  the  surfaces  B  C  and  E  H  ; 
the  negative  plate  and  the  small  wedge 
are  fixed,  while  the  large  wedge  may  be 
moved  along  J  K.  In  moving  the  long 
wedge,  the  surfaces  E  H  and  M  N  remain 
always  parallel,  so  that  the  two  wedges 
form  a  positive  quartz-plate  of  variable  thickness.  In  the 
position  of  the  plates  illustrated  in  the  figure,  the  whole  com- 
pensation gives  the  rotation  zero,  as  E  F  =  A  B.  If  the  long 
wedge  is  moved  so  that  L  approaches  J,  the  thickness  of  the 
positive  plate  will  exceed  that  of  the  negative,  and  the  wedge- 
compensation  will  produce  a  positive  rotation  with  which  the 
negative  rotation  of  an  active  body  may  be  compensated.  If, 
on  the  other  hand,  the  large  wedge  is  shoved  in  the  opposite 
direction,  so  that  N  approaches  K,  then  the  thickness  of  the 
negative  plate  is  in  excess,  and  positive  rotations  which  are 
not  too  large  may  be  compensated.  The  greatest  possible 
change  in  thickness  is  secured,  the  longer  the  large  wedge  is 


Fig- 


368  SACCHARIMETERS 

made,  and  the  greater  the  wedge  angle.  Practically  the  long 
wedge  is  not  shoved  along  J  K,  but  the  two  wedges  are  sepa- 
rated as  shown  in  Fig.  51  below,  and  then  the  long  wedge  is 
so  moved  that  the  surface  M  N  remains  in  the  same  relative 
position  parallel  to  E  H.  But  as  the  layer  of  air  remaining 
between  the  two  wedges  effects  a  lateral  displacement  of  the 
whole  system  of  rays  going  through  the  apparatus,  the  two 
wedges  are  separated  no  further  than  is  absolutely  necessary 
to  permit  the  free  motion  of  the  large  wedge.  This  displace- 
ment of  the  rays  by  the  air  explains  also  why  the  wedge-com- 
pensation does  not  give  exactly  zero  rotation  when  the  thick- 
ness of  the  two  wedges  together  is  exactly  equal  to  that  of  the 
negative  plate.  If  the  mounting  of  the  large  wedge  is  fur- 
nished with  a  scale,  the  displacement  of  this,  with  reference 
to  a  fixed  vernier,  is  directly  proportional  to  the  change  of  thick- 
ness of  the  positive  plate. 

Now,  let  us  suppose  the  apparatus  illuminated  by  white 
light,  it  being  assumed,  of  course,  that  the  polarizer  permits 
this,  which  is  the  case  with  the  accurate  Lippich  half-shadow 
instrument,  and  let  the  analyzer  be  turned  to  optical  equilib- 
rium. Then  on  inserting  the  wedge-compensation  again 
between  polarizer  and  analyzer,  it  will  be  found  that  optical 
equilibrium  is  restored  when  the  large  wedge  is  turned  so  as 
to  indicate  zero  rotation.  This  appears  simultaneously  for 
rays  of  all  wrave-lengths,  because  the  rotation  dispersion  is  the 
same  for  positive  and  negative  quartz-plates.  But,  at  the  same 
time,  it  is  found  that  because  of  this  rotation  dispersion,  the  rota- 
tion of  such  active  bodies  only,  as  have  the  same  dispersion  as 
quartz,  may  be  compensated  by  the  wedge-combination.  The 
rotation  of  quartz-plates  in  the  first  place  may  be  compensated, 
and  also  that  of  sugar  solutions,  since,  as  shown  in  §45,  the 
rotation  of  cane-sugar  is  very  nearly  the  same  as  that  of  quartz. 
It  is  because  of  this  fact  that  the  construction  of  saccharim- 
eters,  which  may  be  employed  with  white  light,  is  possible. 

123.  Double    Wedge-Compensation    of    Schmidt    and    Haensch.— 

In   the  double  wedge-compensation    system    introduced  in 

saccharimetry  by  Schmidt  and  Haensch,  the  negative  plate  of 

Fig.  51  is  replaced  by  two  negative  quartz-wedges  of  the  same 


THE   SUGAR    SCALE 


369 


Fig.  52. 


angle,  so  that  the  negative  as  well  as  the  positive  plate  pos- 
sesses a  variable  thickness.  This  double  wedge-compensation 
is  shown  in  Fig.  52.  The  smaller  wedges  are  fixed,  and  the 
large  ones,  as  before,  movable.  The  thick  ends  of  the  large 
wedges  face  in  the  same  direction,  so  as  to  eliminate  as  far  as 
possible,  the  displacement  of  an  air  layer  between  the  wedges. 
Ordinarily,  the  wedge  angles  of  the  negative  wedges  are  made, 
as  nearly  as  possible,  equal  to  those  of  the  positive.  As  may 
be  readily  seen,  it  is  possible  wTith  this  combination  to  compen- 
sate negative  as  well  as  positive  rotations.  Its  great  advantage 
over  the  single  wedge  arrangement  is 
found  in  the  fact  that  it  does  not  give  the 
zero-rotation  for  a  single  position  only  of 
the  large  wedges  as  shown,  for  example, 
in  Fig.  52,  but  for  any  position  of  the  one 
wedges,  a  corresponding  one  of  the  other 
may  be  found  for  which  the  rotation  is 
again  zero.  This  follows  from  the  fact 
that  the  thicknesses  of  the  positive  and 
negative  plates  are  changed  to  the  same  extent  by  movement  in 
the  same  direction.  A  small  rotation  may,  therefore,  be  com- 
pensated several  times  by  choosing  different  parts  of  the  large 
wedges,  so  that  it  is  possible  to  largely  eliminate  wedge  errors  by 
taking  the  mean  of  these  several  determinations.  Other  facts 
concerning  double  wedge-compensation  can  be  brought  out  in 
the  discussions  of  the  following  paragraphs. 

124.  Preparation  of  a  Sugar  Scale  for  Polariscopes  with  Circular 
Graduation. — The  following  paragraphs  deal  with  the  sugar  scale 
introduced  into  German  saccharimetry  by  Ventzke,  which  is 
naturally  the  most  important  part  of  the  saccharimeter.  We 
enter  upon  a  field  in  which,  unfortunately,  much  uncertainty 
still  exists,  and  in  part  must  exist,  since  experimental  investi- 
gations in  this  direction  have  not  yet  handled  the  subject  with 
sufficient  completeness  or  accuracy.  For  this  reason,  in  the 
following,  many  points  will  be  touched  upon  only  briefly,  and 
others  not  at  all.  Above  all,  it  must  be  explained  at  the  start, 
the  method  will  not  be  indicated  here  which  alone  can  lead  to 
a  scientifically  unobjectionable  sugar  scale.  Complete  clear- 
ness and  accuracy  in  this  field  can  be  expected  only  after  the 
24 


370  SACCHARIMETERS 

conclusion  of  the  extended  investigations  which  have  been 
undertaken  by  the  Reichsanstalt. 

It  is  important  in  practice  to  have  a  scale  which  shows  directly 
in  per  cent  the  amount  of  sugar  in  the  substance  investigated. 
It  will  be  assumed  in  all  that  follows,  that  a  constant  tempera- 
ture of  say  20°  is  maintained.  Let  a  grams  of  pure  sugar  be 
dissolved  in  enough  water  to  make  a  solution  of  exactly  100 
cc.  and  then  polarize  the  solution  in  a  20  cm.  tube  of  the  Lip- 
pich  polarimeter,  using  sodium  light ;  let  the  observed  angle  be 
ft.  We  shall  consider  a  as  the  normal  weight  and  designate 
the  solution  made  as  the  normal  sugar  solution.  Next  assume 
a  solid  or  liquid  substance  which  contains  along  with  sugar, 
only  such  bodies  as  are  inactive  and  soluble  in  water.  In  100 
grams  of  this  substance  let  there  be  present  p  grams  of  pure 
sugar ;  then  p  is  the  percentage  amount  of  sugar  and  the  determi- 
nation of  this  is  the  problem  of  optical  saccharimetry.  Dissolve 
now  a  grams  of  this  substance  in  water,  dilute  to  100  cc.  and 
polarize  as  before  in  the  20  cm.  tube  ;  the  observed  angle  is 
now  y.  For  aqueous  sugar  solutions  the  rotation  is  known 
to  be  proportional  to  the  concentration  ;  that  is,  to  the  number 
of  grams  in  loocc.  of  the  solution  (as  this  is  not  absolutely 
true,  the  variations  and  corrections  will  be  discussed  later). 
As  the  concentration  of  the  normal  sugar  solution  is  «,  and 
that  of  the  second  solution  o.oi  a  p,  then  it  follows  that 

ft  :  y  :  :  a  :  o.oi  a  p,   from  which  p~  ,  or  also,  ft  :  y  :  : 

loo  :  p  ;  that  is,  the  two  angles  of  rotation  are  related,  as  are 
the  percentage  strengths  of  the  original  substances,  the  strength 
of  the  pure  sugar  being,  of  course,  100  per  cent.  Now,  if  we 
take  ft  =  loo,  y  will  be  equal  top,  and  in  polarizing,  we  read 
directly  the  desired  percentage  strength.  Therefore,  in  order 
to  find  the  percentage  amount  of  sugar  in  a  substance,  it  is 
only  necessary  to  polarize  in  a  20  cm.  tube,  a  solution  of  the 
substance  which  contains  the  normal  weight  dissolved  to  make 
loo  cc.  As  seen,  this  normal  weight  may  be  chosen  quite  arbi- 
trarily ;  the  length  only  of  the  sugar  scale  depends  on  it,  as  this 
is  proportional  to  the  normal  weight.  We  shall  apply  this 
sugar  scale  of  the  polarimeter  now  to  the  saccharimeters. 


SUGAR  SCALE  FOR  SACCHARIMETERS  371 

125.  Preparation  of  the  Sugar  Scale  for  Saccharimeters. — Let  the 
analyzer  of  the  polarization  apparatus,  using  white  light,  be 
brought  into  the  position  of  optical  equilibrium  and  insert  the 
single  Soleil  wedge-compensation  between  the  analyzer  and 
analyzer  diaphragm,  so  as  to  be  able  to  compensate  the  positive 
rotation  of  sugar  solutions.  We  assume  the  constant  tempera- 
ture of  say  20°,  and,  for  the  moment,  perfect  equality  in  the 
rotation  dispersion  of  sugar  and  quartz.  Then  let  the  large 
wedge  be  so  moved  that  optical  equilibrium  still  obtains,  and 
at  some  convenient  point  on  the  setting  of  the  large  wedge 
make  a  mark  to  be  designated  as  o.  This  mark  prolonged  to 
the  fixed  framework  of  the  mounting,  gives  the  fixed  index 
position.  In  this  way  the  zero-point  of  the  apparatus  is  deter- 
mined. Then  the  normal  sugar  solution  in  the  20  cm.  tube  is 
inserted,  and  the  large  wedge  is  moved  until  optical  equilib- 
rium is  secured  again.  A  second  mark  is  now  made  on  the 
large  wedge,  opposite  the  fixed  index  mark,  and  this  is  desig- 
nated loo.  In  this  manner,  the  extremely  important  TOO 
mark  of  the  instrument,  upon  the  accuracy  of  which  every- 
thing depends,  is  established.  If,  next,  the  interval  between 
the  o  mark  and  the  100  mark  is  divided  into  a  convenient 
number  of  exactly  equal  divisions,  the  instrument  is  ready  for 
use.  As  the  displacement  of  the  large  wedge  is  exactly  pro- 
portional to  the  amount  of  rotation  of  the  inserted  sugar  solu- 
tion, it  follows  that  the  percentage  strength  of  pure  sugar  may 
be  again  read  off  directly  on  the  scale.  If  the  normal  weight  of 
a  substance  is  dissolved  in  water,  diluted  to  100  cc.,  and  if  the 
solution  is  polarized  in  a  20  cm.  tube,  the  number  read  on  the 
scale  gives  the  percentage  amount  of  pure  sugar  present. 

Imagine  next  a  positive  quartz  plate,  perfectly  plane  paral- 
lel, and  cut  perpendicularly  to  the  optical  axis,  and  of  such 
a  thickness  that  it  gives  the  100  point  in  an  accurately  gradu- 
ated saccharimeter.  By  the  aid  of  such  a  plate,  it  will  now  be 
much  easier  to  control  the  100  mark  of  instruments  than 
through  the  use  of  a  normal  sugar  solution,  the  exact  prepa- 
ration of  which  requires  the  expenditure  of  much  time.  A 
quartz-plate  so  made  is  called  a  normal  quartz-plate,  and,  as  a 
matter  of  fact,  all  saccharimeters  are  in  practice  graduated  by 
it.  Normal  quartz-plates  are  to  be  defined,  naturally,  by  their 


372  SACCHARIMETERS 

rotation  and  not  by  their  thickness,  because  the  latter  cannot 
by  any  means  be  as  accurately  measured  as  the  rotation.  It  need 
hardly  be  remarked  that  saccharimeters  may,  of  course,  be 
graduated  with  quartz-plates  which  do  not  polarize  exactly 
loo,  as  long  as  it  is  known  to  what  value  on  the  sugar  scale 
they  correspond. 

126.  The  Ventzke  Sugar  Scale. — The  normal  weight  has  not 
been  numerically  defined  in  the  preceding  paragraphs,  because 
it  may  be  arbitrarily  chosen,  and  in  the  course  of  time  has 
been  frequently  changed.  At  the  present  time,  only  two  sugar 
scales  are  found  in  common  use,  the  German  or  Ventzke  scale, 
and  the  French  scale,  of  which  the  first  only  will  be  discussed. 
The  French  scale1  must  be  considered  as  quite  unsatisfactory 
as  its  hundred  point  is  defined  by  the  rotation  of  a  quartz-plate 
i  mm.  in  thickness.  This  use  of  the  thickness  of  a  quartz- 
plate  in  the  definition  of  a  sugar  scale  is1  not  alone  wholly  un- 
necessary, but  it  is  also  very  unpractical,  because  as  often  as 
the  absolute  rotation  of  i  mm.  of  quartz  is  differently  deter- 
mined, it  is  necessary  to  correspondingly  change  the  normal 
weight  ;  this  explains  why  it  is  that  the  French  normal  weight 
has  been  changed  at  least  once  in  every  ten  years. 

Ventzke'2  proposed,  first,  a  method  for  preparing  the  normal 
sugar  solution,  which  was  intended  to  render  the  use  of  a 
balance  unnecessary.  He  defined  as  the  normal  sugar  solution, 
a  solution  of  pure  sugar  in  water  which  should  have  at  17.5° 
the  specific  gravity  of  i.ioo,  referred  to  water  at  17.5°.  To 
determine  then  the  polarizing  sugar  of  any  substance,  it  would 
be  simply  necessary  to  prepare  a  solution  of  it  of  this  density 
by  aid  of  an  aerometer.  But  naturally  this  method  could  not 
give  exact  results,  because  the  salts  in  the  cane-sugars  to  be 
investigated  have  an  effect,  and  have  usually  a  density  differ- 
ent from  that  of  sugar  itself  ;  it  was,  therefore,  soon  abandoned. 
But  as  the  100  point  of  many  saccharimeters  had  already  been 
fixed  by  aid  of  the  normal  sugar  solution  of  i.i  sp.  gr.,  and 

1  The  French  scale  is  described  in  this  way  :  That  sugar  solution  lias  the-  normal 
weight  whose  rotation  in  a  20  cm.  tube  is  equal  to  that  of  a  quartz  plate  i  mm.  in 
thickness.  The  normal  weight  thus  defined  ha^  suffered  many  changes  in  the  course 
of  time,  as  it  has  vark-d  between  the  limits,  16.02  and  16.471  gram.  These  two  weights 
differ  by  about  2.8  per  cent. 

-  Vent/.ke  :  Krdm.  Jour,  fur  prakt.  Chem.,  35,  84  (1842)  ;  a8,  m  (1843). 


SUGAR    SCALE    FOR   SACCHARIMETERS  373 

as  it  was  not  desirable  to  change  the  scale  once  introduced,  the 
concentration  of  the  Ventzke  normal  solution  at  17.5°  was  then 
determined.  Investigations  showed  that  100  cc.  of  such 
a  solution  contains  26.048  grams  of  sugar  weighed  in  air 
with  brass  weights.  The  normal  weight  should  be  then 
26.048  grams.  If  then  this  weight  of  pure  sugar  is  dis- 
solved to  make  100  cc.  and  polarized  in  the  20  cm.  tube,  the 
100  point  on  the  Ventzke  scale  is  again  found.  As  this  method 
was  in  use  long  before  the  Mohr  cubic  centimeter  was  sug- 
gested, the  number  26.048  must  certainly  have  been  applied  to 
true  cubic  centimeters.  After  the  introduction  of  the  Mohr 
graduated  flasks,  the  instrument  makers,  especially  Schmidt 
and  Haensch  in  Berlin,  began  to  employ  a  solution  of  26.048 
grams  of  sugar  in  100  Mohr  cubic  centimeters  in  fixing  the  100 
mark  of  instruments.  For  a  number  of  years,  then,  the  defi- 
nition of  the  normal  sugar  solution  has  been  this  :  That  sugar 
solution  has  the  normal  strength  which  contains  at  17.5°  in  100 
Mohr  cubic  centimeters,  26.04.8 grams  of  cane-sugar  weighed  in 
the  air  with  brass  weights. 

As  the  Mohr  cubic  centimeters  have  continually  given  rise 
to  error,  it  was  finally  determined  to  go  back  to  true  cubic 
centimeters.  This  last  definition  of  the  normal  sugar  solution 
will  then  be  changed  so  as  to  correspond  to  true  cubic  centi- 
meters. The  following  is  the  definition  of  the  Mohr  cubic  centi- 
meter.1 If  100  grams  of  water  are  weighed  in  the  air  with  brass 
weights  at  17.5°,  the  volume  is  100  Mohr  cubic  centimeters. 
If  we  take  into  consideration,  the  weight  of  the  air  displaced 
in  weighing  and  the  specific  gravity  of  the  water  at  17.5°,  it 
follows  that  loo  Mohr  cc.  ==  100.234  true  cc.2  Therefore,  the 
definition  of  the  normal  sugar  solution  for  true  cubic  centi- 
meters is  this  :  A  sugar  solution  has  the  normal  concentration 
when  it  contains  25.9872  grams  of  cane-sugar,  weighed  in  air 
with  brass  weights,  dissolved  in  water  to  make  100  cubic  centi- 
meters at  17.5°.  As  again  appears  from  the  lack  of  agree- 
ment in  the  specific  gravity  of  sugar,  and  the  substances  whose 
sugar  content  is  to  be  determined,  it  would  be  neces- 

1  Mohr:  Chemisch-analytische  Titrirmethode,  44-50  (1886). 

-  The  Mohr  flasks  made  by  the  firm  of  Schmidt  and  Haensch  hold,  as  experi- 
ments of  the  author  show,  in  fact  within  ±0.03  per  cent,  of  100.23  true  cubic  centi- 
meters. 


374  SACCHARIMETERS 

sary  to  reduce  all  weights  to  vacuo  to  secure  a  perfectly 
accurate  result.  As  the  specific  gravity  of  pure  sugar  is 
1.6,  the  25.987  grams  in  real  mass  is  26.003  grams. 
The  normal  sugar  solution  contains  then  26.003  true  grams  of 
sugar  dissolved  at  17.5°  to  make  100  true  cubic  centimeters. 
But  in  what  follows  we  shall  retain  the  air  weighings,  as  the 
error  made  by  neglecting  the  reduction  amounts  seldom  to  0.05 
per  cent.,  which  has  no  importance  in  practice.  Finally,  it 
must  be  added  that  the  variations  in  the  normal  weight  from 
changes  in  the  density  of  the  air  amount  to  about  ±  0.0007 
grams  for  26  grams  of  sugar,  and  are  likewise  unimportant  in 
practice. 

Retaining  then  the  long  established  definition  of  the  100 
point,  the  preparation  of  the  Ventzke  sugar  scale,  and  the 
determination  of  sugar  in  a  substance  are  as  follows  :  A  normal 
sugar  solution  is  made  by  dissolving  26 .04.8  grams  of  pure  cane- 
sugar,  weighed  with  brass  weights  in  air,  in  a  100  cc.  Mohr 
flask  at  77.5°,  and  this  is  polarized  at  17.5°  in  a  20  cm.  tube  in 
the  saccharimeter,  care  being  taken  to  keep  the  wedge-compensa- 
tion also  at  17.5°  ;  this  establishes  the  100  mark  (100°  V)  of  the 
saccharimeter .  Then  by  weighing  and  dissolving  26.04.8  grams 
of  an  impure  sugar  under  the  same  conditions,  and  polarizing 
in  the  same  tube,  the  compensation  still  at  77.5°,  the  Ventzke 
scale  gives  directly  the  amount  of  pure  sugar  in  per  cent. 

Now,  in  regard  to  the  accuracy  with  which  the  saccharim- 
eters  in  the  hands  of  sugar  chemists  agree  with  this  definition 
of  the  true  100  mark,  nothing  definite  can  be  said.1  Certainty 
with  reference  to  the  accuracy  of  the  100  point  on  the  Ventzke 
scale  will  be  established  by  the  investigations  of  the  Reichsan- 
stalt. 

127.  The  100  Point  of  the  Saccharimeter.— Suppose  the  100  point 
of  a  saccharimeter  accurately  determined  by  means  of  a  correct 
normal  sugar  solution,  and  then  a  normal  quartz-plate  made 
which  polarizes  exactly  100°  V  in  the  so-graduated  instrument. 
Then  by  aid  of  this  plate,  new  saccharimeters  may  be  much 
more  accurately  graduated  than  with  freshly  prepared  sugar 

1  The  work  of  Nasini  and  Villavecchia  (Sul  peso  normale  pei  saccarimetri,  Puhhl. 
d.  I«ab.  chim.  centr.  d.  Gab.  1891.  Oesterr.-Ungar.  Zeitschrift  f.  Zuckerindustrie,  I 
Heft,  1892)  adds  nothing  to  the  discussion. 


THE    100   POINT   OF   THE   SACCHARIMETER  375 

solutions.  In  the  first  place  such  a  solution  would  always 
vary  more  or  less  from  the  correct  normal  solution;  and, 
secondly,  it  would  be  only  with  the  greatest  difficulty  that  the 
normal  temperature  required  by  the  definition  could  be  main- 
tained, especially  in  the  quartz  compensation.  But  the  normal 
quartz -plate  remains  always  applicable  and  correct,  and  its  rota- 
tion in  the  saccharimeter  is  independent  of  the  temperature,  as 
long  as  care  is  taken  to  have  the  plate  and  compensation  wedge 
at  the  same  temperature,  because  the  temperature  coefficient  of 
positive  and  negative  quartz-plates  is  the  same.  For  a  long 
time,  therefore,  all  saccharimeters  have  been  graduated  with 
such  normal  quartz-plates,  which  goes  to  explain  the  remark- 
able agreement  in  the  100  points  of  the  instruments  purchased 
from  dealers. 

The  loo  points  on  the  saccharimeters  made  by  Schmidt  and 
Haensch  in  Berlin,  which  are  now  used  in  all  parts  of  the 
world,  seldom  differ  by  more  than  0.05  to  o.  i°  V,  and  the  dif- 
ferences are  usually  smaller.  It  was,  therefore,  very  com- 
mendable that  the  firm  of  Josef-Jan  Fric  in  Prague,  which 
also  began  the  construction  of  saccharimeters,  should  bring 
their  instruments  into  exact  agreement  with  those  of  Schmidt 
and  Haensch.  How  then  may  the  100  point  on  these  saccharim- 
eters be  defined  ?  This  can  be  most  simply  done  through  the 
rotation  of  the  normal  quartz-plate  for  some  definite  light,  as  the 
sodium  ray.  Experiments  by  Schonrock1  with  four  quartz- 
plates  of  about  100.3°,  93-5°.  9I-7°  and  75-4°  V  in  a  Schmidt 
and  Haensch  half-shadow  saccharimeter,  and  experiments  by 
Josef-Jan  Fric2  with  a  normal  quartz-plate  and  a  plate  of  about 
99.7°  V,  in  a  large  number  of  saccharimeters,  have  shown  in 
complete  agreement  that  the  normal  quartz-plate  at  17.5°  rotates 
the  sodium  ray  34.68°  ±  o.o2°.3  It  should  be  remarked  that 
the  quartz-plates  and  compensations  were  kept  at  the  same 
temperature  in  the  saccharimeters  during  the  experiments,  and 
that  the  result  is  independent  of  the  composition  of  the  white 
light  used,  as  the  differences  for  different  lamps  remained 
below  0.03°  V.  Therefore,  we  can  take  for  quartz-plates  : 

100°  Ventzke  =  34.68  circular  degrees  for  D  at  17.5°  C.4 

1  Schonrock  :  Ztschr.  fur  Instrum.,  16,  242  (1896). 

2  Personal  communication  to  the  author. 

3  The  optical  center  of  gravity  of  sodium  light  =  589.3  MM- 
*  Or,  100°  V  =  34.69°  arc  for  D  at  20°. 


376  SACCHARIMETERS 

The  number  34.68  is  called  the  factor  of  reduction.  If  a 
quartz-plate  is  polarized  in  a  saccharimeter  with  its  tempera- 
ture kept  equal  to  that  of  the  wedge-compensation,  and  if  it 
shows  a°  V,  then  the  quartz- plate  will  have  a  rotating  power 
for  sodium  light  equal  to  0.3468  a  dr  0.0002  a  circular  degrees 
at  17.5°.  More  about  the  reduction  factors  for  substances 
other  than  quartz,  will  be  found  in  §129  and  §153.  If  the 
rotation  of  a  quartz-plate  i  mm.  thick,  at  17.5°,  for  sodium 
light  is  21.714°,  the  thickness  of  the  normal  quartz-plate  must 
be  about  1.597  mm- 

The  following  may  be  said  about  the  dimensions  commonly 
chosen  in  the  quartz  wedge-compensations  used  in  saccharim- 
eters.  The  wedge  angle  of  the  quartz  is  usually  taken  at  3°, 
so  that  the  distance  between  the  o  and  100  points  on  the  scale 
is  about  30.5  mm.  The  whole  interval  is  divided  into  100 
equal  parts,  and  by  a  vernier,  one-tenth  Ventzke  may  be  read 
off.  In  the  simple  wedge-compensation,  the  two  wedges  are 
usually  positive,  and  the  compensation  plate  negative  and 
about  4.3  mm.  in  thickness.  If  the  large  wedge  is  then  moved 
toward  the  100  point,  the  thickness  of  the  two  wedges  de- 
creases. 

128.  Testing  the  Saccharimeter  Scale. — As  the  agreement  of  dif- 
ferent saccharimeters  at  the  100  point  leaves  little  to  be  desired, 
it  may  be  asked  now  how  the  scale  of  a  single  instrument  may 
be  tested  between  the  zero-point  and  100  point.  The  error  in 
graduation  in  the  scale  and  vernier  should  remain  everywhere 
below  0.05°  V.  The  ivory  scales  formerly  commonly  used 
have  been  abandoned,  and  properly,  because  their  length  is 
influenced  by  the  moisture  in  the  air  ;  the  changes  amount  to 
0.3°  V  and  more.  The  nickelin  scales  now  commonly  used  are 
free  from  this  error,  and  are  also  independent  of  changes  in 
temperature  as  the  change  in  length  between  o  and  100,  with 
a  temperature  fluctuation  of  10°,  is  only  about  0.01°  V. 

Furthermore,  the  wedge  should  give  correct  results  at  all 
parts  of  the  scale;  that  is,  it  should  be  so  made  that  when  it  is 
moved  through  the  nth  part  of  the  whole  distance  ( 100°  V) ,  the 
change  of  rotation  produced  in  the  compensation  should  be  the 
wth  part  of  the  rotation  of  the  normal  plate  corresponding  to 
the  loo  point  on  the  scale.  This  would  be  the  case  exactly  if 


THE   100  POINT  OF  THE  SACCHARIMETER  377 

the  large  wedge  were  perfectly  plane  on  both  sides,  optically 
homogeneous,  and  its  motion  without  error.  Errors  in  the 
construction  and  character  of  the  small  wedges  and  the  com- 
pensation plate  are  of  less  importance  as  they  are  fixed  in  posi- 
tion, and  because  the  wedge-compensation  is  close  to  the 
analyzer,  while  the  polarizer  is  focused  with  the  telescope  ; 
the  rays  from  the  whole  field  of  view7  pass  through  the  two 
small  wedges  and  the  plate  and  uniformly  over  their  whole  ex- 
tent. As  regards  the  large  wredge,  it  is  possible  with  sufficient 
care  to  make  its  surfaces  so  plane  that  the  error  occasioned 
here  in  the  saccharimeters  is  inappreciable.  Aso. i°  V  cor- 
responds about  to  0.0016  mm.  in  thickness  of  the  wredge,  the 
notion  has  become  common  that  the  surfaces  bounding  the 
wedge  cannot  vary  16/i0  ooo  of  a  millimeter  from  absolute  planes, 
if  it  is  to  give  readings  correct  to  within  o.  i  °  V  ;  but  as  it  is 
impossible  to  make  the  whole  facing  surfaces  of  the  wedge,  30 
mm.  long,  as  perfectly  plane  as  this,  the  errors  often  amount- 
ing to  tenths  of  Ventzke  degrees  are  supposed  to  be  explained. 
But  all  of  this  is  based  on  error  ;  the  consideration  would  be 
true  only  when  a  single  ray  were  dealt  with.  In  reality,  how- 
ever, we  work  with  a  whole  field  whose  length  is  about  a 
sixth  of  the  whole  wedge-length.  If  it  is  considered  further 
that  the  wedge  is  placed  right  at  the  analyzer,  it  may  be  under- 
stood that  a  slightly  convex  or  concave  bounding  surface  on 
the  wedge  hurts  nothing.  Errors  are  occasioned  only  when 
the  radius  of  curvature  has  not  a  constant  sign  ;  that  is,  when 
points  of  inflection  are  present,  but  such  surfaces  are  seldom 
met  with.  The  optician  can,  in  fact,  prepare  the  wedge  so  that 
no  errors  need  result  from  faults  of  construction.  Then  how 
may  it  be  accounted  for  that  variations  amounting  to  several 
tenths  of  a  Ventzke  degree  are  almost  the  rule  ?  The  answer 
to  this  question  is  simple,  but  not  very  encouraging.  Nearly 
all  errors  which  are  found  are  due  to  the  optical  impurity  of 
the  quartz  wedges.1  It  must,  unfortunately,  be  admitted  that 
quartz  is  a  very  poor  material,  so  that  one  rarely  comes  into 
possession  of  optically  faultless  plates  of  i  to  2  square  centi- 
meters of  surface  ;  it  must  even  be  considered  a  piece  of  good 
fortune  to  possess  a  pure  quartz-wedge  3  cm.  long  and  of  cor- 

1  See  "  Die  Thatigkeit   der  physikalisch-technischen  Reichsanstalt  "  under  Brod- 
hun  and  Schonrock  ;  Ztschr.  fur  Instr.,  17.  (1897). 


378  SACCHARIMETERS 

responding  thickness.  If  now  we  examine  the  wedge-com- 
pensations further  in  respect  of  their  optical  purity,  it  must 
seem  in  many  cases  impossible  that  with  such  material  such 
delicate  observations  could  be  made,  when  the  mean  error  of 
an  adjustment  is  only  about  =fc  0.03°  V  ;  yet  this  is  the  case 
with  the  half-shadow  saccharimeters.  This  is  explained  by 
the  fact  that  the  wedge-compensation,  fortunately,  is  located 
at  the  analyzer,  so  that  its  image,  with  a  correct  path  of  the 
rays,  according  to  §96,  coincides  with  the  plane  of  the  pupil 
of  the  eye  and  the  impurity  therefore  cannot  be  recognized. 
Now,  if  the  large  wedge  be  moved  new  and  different  parts  are 
then  passed  by  the  rays,  and  the  rotations  of  these  may  differ 
considerably  from  each  other.1  But  as  the  irregular  parts  of 
the  wedges  appear  only  gradually  in  the  portion  of  the  field 
occupied  by  the  rays,  the  errors  in  a  saccharimeter  do  not  show 
sudden  changes  from  point  to  point,  but  are  subject  to  gradual 
variations,  as  the  author  has  had  opportunity  of  observing. 
Therefore,  if  the  errors  are  determined  for  say  5°,  10°,  15° 
V  and  so  on,  and  if  these  are  plotted  on  coordinate  paper,  with 
the  Ventzke  degrees  as  abscissas  and  the  errors  as  ordinates,  it 
will  be  possible  to  find  from  the  curve  passed  through  the  tops 
of  the  ordinates,  the  errors  for  any  intermediate  points.  The 
simplest  and  at  the  same  time  the  best  method  of  finding 
errors  is  through  the  examination  of  different  parts  of  the  scale 
with  good  quartz  plates.  But  as  this  is  not  always  practicable 
for  the  individual  owners  of  saccharimeters,  other  methods  of 
error  determination  have  been  devised. 

Accurate  results  are  alone  furnished  by  the  control  observa- 
tion tubes  made  by  Schmidt  and  Haensch  and  described  in 
§163.  These  give  more  accurate  results  than  the  preparation 
of  a  large  number  of  solutions  of  proper  rotation  for  the  reason 
that  in  the  control  tubes,  relative  measurements  only  need  be 
made  as  soon  as  the  100  point  is  once  for  all  accurately  deter- 
mined. The  control  observation  tubes  are  constructed  on  the 

1  The  author  onre  had  the  opportunity  of  examining  two  plane  parallel  quartz- 
plates  about  5  mm.  thick  and  well  made,  which,  when  polarized  in  a  half-shadow 
apparatus  with  sodium  light  and  large  half-shadow,  that  is,  with  rather  bright  field, 
gave  pretty  constant  results,  but  when  the  plates  were  turned  in  their  planes  the 
angles  of  rotation  assumed  all  values  between  o°  and  90°.  Although  quartz-wedges  of 
corresponding  bad  quality  could  hardly  be  found,  it  cannot  be  denied  that  the  error 
of  a  saccharimeter  must  be  largely  ascribed  to  the  optical  impurity  of  the  wedges. 


THE   100  POINT  OF  THE  SACCHARIMETER  379 

principle  of  making  the  length  of  the  rotating  liquid  column 
variable  and  the  variation  measurable.  As  the  deflection  of 
the  plane  of  polarization  is  proportional  to  the  length  of  the 
liquid  layer,  the  rotation  decreases  in  the  same  degree  as  the 
length  of  the  column.  The  examination  with  the  control  tube 
is  then  made  in  the  following  manner  :  To  avoid  unnecessary 
corrections,  the  zero  of  the  vernier  is  brought  into  exact  agree- 
ment with  the  zero  of  the  scale,  using  the  vernier  correction 
in  aid  of  this.  Then  the  100  point  must  be  at  exactly  the 
right  distance  from  the  tw7o  zero  points,  which,  according  to 
§127,  is  nearly  always  the  case.  Then  the  control  tube  is 
filled  with  a  sugar  solution  whose  rotation  is  somewhat  greater 
than  100°  Ventzke,  when  the  tube  is  pulled  out  to  its  full 
length.  The  tube  is  then  shortened  until  the  rotation  gives 
exactly  a  =  100°  V,  when  the  length  /  is  measured  accurately . 
If  the  conditions  of  experiment,  and  most  important,  the  tem- 
peratures of  the  wedge-compensation  and  the  sugar  solution, 
are  kept  constant  and  the  length  of  the  tube  then  shortened  to 
/',  the  rotation  corresponding  to  this  length  is  b  =  a  I' II.  If 
instead  of  reading  off  b,  the  value  read  is  exactly  b*  V,  then 
the  error  in  the  immediate  neighborhood  of  the  point  ^  is 
given  by/  =  b  —  b^  =  (a  I'll)  —  b^  ;  this  error,  /,  is  to  be  added 
algebraically  to  the  observed  value  b^  in  order  to  obtain  the 
true  value  of  dl  in  Ventzke  degrees.  In  this  way,  the  errors 
of  any  desired  number  of  points  on  a  considerable  portion  of 
the  scale  may  be  found,  and  the  length  of  this  is  limited  simply 
by  the  extent  to  which  the  tube  may  be  shortened.  With 
a  properly  constructed  control  tube,  using  a  single  solution,  it 
is  possible  to  determine  the  errors  from  100°  V  down  to  55°  V. 
Then  the  tube  is  filled  with  a  new  solution  whose  rotation,  at 
full  length,  is  something  over  55°  V,  and  the  point  55°  is 
taken  as  the  new  starting  point,  because  its  error  has  been 
already  determined,  and  then  observations  are  made  as  before 
until  the  error  at  the  5°  mark  is  reached.  The  following  table 
shows  how,  with  five  different  properly  chosen  solutions,  the 
errors  on  the  whole  scale  may  be  found  i1 

1  Absolutely  pure  sugar  is  not  necessary  for  the  purpose. 


SACCHARIMETERS 


The  tube  length  variable  between  42  cm.  and  22  cm. 


Cane  sugar  solution. 


No. 

Concentration,  or  number  of 
grams  of  sugar  in  100  cc. 
of  solution. 

Starting  point. 

o  V. 

Errors  found  at  the 
points. 

I 

12.53 

100 

95,  90,  85  ..-60,  55 

2 

6.89 

55 

50,  45,  40,  35,  30 

3 

3-76 

30 

25,  20,  16 

4 

2.00 

16 

15,  10,  9 

5 

«.I3 

9 

5 

Of  course,  the  accuracy  of  the  tube  scale  itself  must  have 
been  previously  determined.  By  plotting  the  errors  of  the 
'  saccharimeter  scale  on  coordinate  paper  the  error  curve  is 
found.  As  may  be  readily  seen,  this  method  of  rinding  errors, 
in  case  it  is  expected  to  give  really  accurate  results,  requires 
quick  and  very  close  work.  It  is,  therefore,  recommended  to 
make  on  different  days  two  complete  series  of  determinations 
to  secure  a  picture  of  the  accuracy  obtainable.  If  this  is  sat- 
isfactory the  mean  curve  is  taken  as  the  final  one.  Although  the 
testing  of  a  saccharimeter  scale  requires  some  pains,  one  should  not 
hesitate  to  do  the  work,  because  the  errors  remain  constant  and 
are  absolutely  independent  of  time  so  long  as  no  injury  has  hap- 
pened to  the  optical  mechanism  of  the  instrument.  An  error 
curve  once  accurately  established  holds  good  always. 

We  turn  now  to  a  consideration  of  the  double  wedge-com- 
pensation of  Schmidt  and  Haensch  (§123)  on  the  value  of 
which  different  views  have  been  held.  The  zero  point  is 
usually  found  at  the  thinner  end  of  the  long  wedge,  so  that 
the  working  wedge  is  negative  and  the  control  wedge  positive. 
To  avoid  unnecessary  zero  point  corrections  the  control  wedge 
is  placed  exactly  at  o  and  optical  equilibrium  is  secured  by 
moving  the  working  wedge  ;  if  the  zero  point  of  the  working 
scale  does  not  coincide  exactly  with  that  of  the  vernier  the  dif- 
ference is  corrected  as  before  by  means  of  the  micrometer 
screw  below  the  vernier  corresponding  to  the  scale.  Then  the 
working  wedge  is  placed  at  100  and  a  test  is  made  as  accurately 
as  possible  of  the  correctness  of  the  100  mark.  If  now  optical 
equilibrium  is  again  established  by  aid  of  the  control  wedge, 


THE   100  POINT  OF  THE  SACCHARIMETER  381 

this  should  stand  exactly  at  100.  If  this  is  not  the  case  the 
scale  has  been  carelessly  made,  and  the  apparatus  should  be 
simply  sent  back  to  the  manufacturer.  Naturally  the  two 
scale  lengths  are  usually  not  the  same,  which  is  not  necessary. 
If  the  two  wedges  are  accurately  made  it  must  follow  that 
when  one  of  them  is  put  on  any  point  of  its  scale  optical 
equilibrium  must  obtain  wrhen  the  other  is  placed  at  the  same 
point  on  its  scale.  If  in  this  way  the  two  wedges  are  tested 
from  5°  to  5°  and  if  the  differences  in  readings  actually 
remain  below  0.03°  V.,  it  may  be  said  with  great  prob- 
ability that  the  wedge-compensation  does  not  possess  any  ap- 
preciable error,  because  it  would  be  by  extraordinary  chance 
that  any  errors  due  to  optical  impurities  in  certain  places  in 
one  wedge  would  be  exactly  compensated  by  corresponding 
errors  in  the  other.  In  addition  to  all  this,  in  order  to  be  cer- 
tain, it  is  well  to  test  at  least  a  few  points  by  aid  of  the  control 
tube.  As  a  rule,  however,  it  will  be  found  in  testing  the  two 
wedges  as  above  that  the  differences  in  the  readings  in  certain 
parts  of  the  scale  amount  to  some  tenths  of  a  Ventzke  degree, 
so  that  an  accurate  determination  of  errors  is  here  also  re- 
quired. For  this  purpose  the  reading  differences  from  5°  to 
5°  V.  must  be  accurately  found  in  this  way.  The  control 
wedge  is  placed  at  95°  exactly,  and  five  adjustments  at  optical 
equilibrium  are  made  with  the  working  wedge,  from  which  the 
mean  is  taken  and  subtracted  from  95,  to  give  the  reading  dif- 
ference. In  this  way  results  are  obtained  down  to  the  5° 
mark.  Then  the  whole  series  of  observations  is  repeated  by 
placing  the  working  wedge  exactly  at  95°  and  so  on,  and  se- 
curing optical  equilibrium  by  aid  of  the  control  wedge.  The 
two  series  of  observations  should  give  the  same  differences  with 
opposite  signs,  within  the  limits  of  errors  of  experiment,  which 
is  to  be  remembered,  in  general,  in  all  error  corrections.  From 
each  two  corresponding  differences  the  mean  of  the  absolute 
values  is  taken  which  is  to  be  used  in  the  further  calculations, 
with  proper  sign  attached.  The  control  wedge  is  next  placed 
exactly  at  o  and  the  complete  determination  of  errors  in  the 
working  wredge  is  made  by  use  of  the  control  observation  tube 
as  fully  explained  above.  From  the  curve  of  errors  for  the 
working  wedge  and  the  table  of  adjustment  differences  for  the 


382  SACCHARIMETERS 

two  wedges  the  error  curve  of  the  control  wedge  may  be  found 
in  a  way  easily  recognized.  The  latter  may  be  found  also 
directly  by  aid  of  the  control  tube  and  positive  sugar  solutions, 
by  placing  the  working  wedge  at  exactly  100  and  finding  the 
errors  in  the  control  wedge  from  5  to  95.  This  furnishes,  at 
the  same  time,  the  best  control  of  the  accuracy  of  all  the  ob- 
servations made.  If  now  the  rotation  of  a  solution  is  found 
with  one  wedge  and  controlled,  after  taking  out  the  solution, 
with  the  other  wedge,  then  after  adding  the  corrections  from 
the  error  curves  the  two  wedges  should  give  exactly  the  same 
result.  //  follows,  therefore,  that  correct  observations  may  be 
made  with  the  double  wedge  combination  and  an  actual  complete 
control  secured  only  when  the  error  curves  of  the  two  wedges  are 
known.  It  appears,  therefore,  that  as  accurate  work  may  be  done 
with  the  single  as  with  the  double  wedge-compensation. 

129.  Observation  of  Solutions  in  the  Saccharimeter — In  the  fol- 
lowing considerations  we  shall  keep  the  half-shadow  saccharim- 
eters  in  mind  as  they  have  completely  displaced  the  color  in- 
struments. As  the  rotation  dispersion  of  sugar  does  not  agree 
absolutely  with  that  of  quartz,  a  slight  but  unimportant  dif- 
ference in  the  colors  of  the  field  of  view  is  found  in  testing 
high  polarizing  sugar  solutions.  Although  this  does  not  inter- 
fere with  the  accuracy  of  the  reading  for  a  practiced  observer, 
the  adjustments  of  different  observers  with  different  degrees  of 
color  sensitiveness,  may  vary  considerably  from  each  other. 
To  eliminate  the  colors  either  a  plate  of  potassium  dichromate 
or  a  cell  with  solution  of  potassium  dichromate  is  placed  be- 
tween the  light  and  illuminating  lens  ;  a  dichromate  plate  in 
the  ocular  is  not  used.  As  regards  the  changes  in  the  rotation 
of  sugar  solutions  for  white  light  of  different  kinds  of  lamps 
it  is  found  that  appreciable  differences  occur  only  when  ob- 
servations are  made  at  one  time  with,  and  at  other  times  with- 
out, dichromate  plates.1  Still  this  point  requires  fuller  syste- 
matic investigation.  With  reference  to  testing  the  saccha. 
rimeter  scale  by  aid  of  the  control  tube  it  must  be  further  re- 
marked that  the  illumination  must  not  vary  during  determina- 
tion of  the  curve  of  errors.  The  curve  finally  found  is,  how- 
ever, independent  of  the  illumination,  as  the  error  in  the  100 

1   /tschr.  fiir  lustrum.,  16,  243  (1896). 


SACCHARIMETER    READING  383 

point  is  placed  equal  to  zero.  If  a  change  is  made  from  one 
light  to  another,  and  a  change  in  the  100  point  follows,  that 
is,  if  the  rotation  of  a  normal  sugar  solution  varies  by  a°  V., 
then  in  a  corresponding  manner  the  point  b  of  the  scale  would 
change  by  o.oi  a  b°  V. 

As  complaints  about  continuous  changes  in  the  zero  points 
of  instruments  are  still  heard  in  practice,  reference  must  be 
again  made  to  §96.  These  changes  may  be  very  easily  avoided. 
The  focal  length  of  the  illuminating  lens  must  be  chosen  so  as 
to  be  equal  to  half  the  distance  between  this  lens  and  the  ana- 
lyzer diaphragm,  and  the  source  of  light  is  placed  as  far  away 
from  the  illumination  lens  as  the  latter  is  distant  from  the 
analyzer  diaphragm,  or  better  so  that  after  putting  the  absorp- 
tion cell  in  position  a  sharp  image  of  the  source  of  light  will 
be  thrown  by  the  illuminating  lens  on  the  analyzer  diaphragm. 
If  this  is  the  case  observations  may  be  made  day  after  day 
without  disclosing  the  slightest  change  in  the  position  of  the 
zero  point,  since  in  the  saccharimeters  the  polarizer  and  analy- 
zer are  fixed  in  definite  positions,  or  at  least  should  be  ;  a  lat- 
eral displacement  of  the  source  of  light  cannot  be  followed  by 
a  zero  point  change. 

If  the  Ventzke  reading  in  the  investigation  of  a  sugar  solu- 
tion is  to  be  converted  into  circular  degrees  referred  to  sodium 
light,  this -may  be  done  as  explained  in  §127  by  aid  of  the  re- 
duction factor  0.3468,  although  this  properly  applies  to  quartz 
plates  only.  An  absolutely  accurate  conversion  is  not  always 
possible,  because  of  the  effects  of  temperature  and  the  varia- 
tions in  the  rotation  with  the  illumination  and  color  sense  of 
the  observer.  Landolt1  has  actually  found  in  the  observation 
of  a  cane-sugar  solution  in  a  Schmidt  and  Haensch  half-shadow 
saccharimeter,  with  a  gas  lamp,  that  a  rotation  of  100°  V.  cor- 
responds to  the  rotation  of  34.65°  ±  0.05°  for  sodium  light. 
But  if  it  is  required  to  accurately  measure  the  rotation  of  a 
sugar  solution  for  sodium  light  this  must  be  done  in  a  polar- 
imeter  actually  illuminated  by  sodium  light. 

130.  Effect  of  Temperature  on  the  Saccharimeter  Reading. — In  or- 
der to  give  an  idea  of  the  error  wrhich  results  through  temper- 
ature changes  in  the  determination  of  cane-sugar  the  errors 
from  several  sources  will  be  discussed  on  the  basis  of  a  tem- 

1  I^andolt:  Her.  d.  chem.  Ges.  ai,  194  (1888). 


384  SACCHARIMETERS 

perature  variation  of  10°.  In  the  saccharimeter  itself  the 
wedge-compensation  only  is  variable  with  the  temperature  ; 
the  zero  point  is  constant,  but  all  other  points  change  in  value. 
As  we  can  take  the  temperature  coefficient  of  quartz  (and 
sugar  also)  as  constant  through  the  interval  considered,  for 
all  wave-lengths,  that  is,  the  rotation  dispersion  as  independ- 
ent of  the  temperature,  a  simple  calculation  shows  that  a  tem- 
perature variation  of  10°  changes  the  100  point  (100°  V.) 
about  -f  0.15°  V.  From  this  it  will  be  recognized  that  the 
temperature  of  the  compensation  must  be  pretty  accurately 
known  if  one  expects  to  polarize  within  a  few  hundredths 
Ventzke.1 

Now  let  us  consider  the  polarization  of  a  cane-sugar  solution 
in  the  saccharimeter,  and  in  order  to  have  a  definite  case  in 
mind  assume  that  we  have  a  normal  sugar  solution  in  a  20  cm. 
tube,  which  must  therefore  polarize  about  100°  V.  If  the  tube 
is  of  glass  its  length  will  increase  with  the  temperature,  and, 
therefore,  the  rotation  of  the  sugar  solution  also.  A  tempera- 
ture elevation  of  10°  corresponds  to  a  change  of  -fo.oi0  V; 
therefore,  the  change  from  this  cause  is  inappreciable  in  ob- 
servations. But  at  the  same  time  the  concentration  of  the  so- 
lution decreases  with  the  increase  in  temperature,  and  the  ro- 
tation must  therefore  decrease.  As  the  coefficient  of  expan- 
sion of  a  normal  sugar  solution  at  about  20°  is  0.000291,  the 
increase  of  temperature  through  10°  produces  a  change  in  ro- 
tation of  —  o.  29°  V.  Besides  this  the  specific  rotation  of  cane- 
sugar  decreases  with  increase  in  temperature,  so  that  the  angle 
of  rotation  still  further  decreases  ;  the  older  observations  of 
Tuchschmid,  Seyffart,  and  Andrews,  which  gave  the  specific 
rotation  of  cane-sugar  as  constant  at  different  temperatures, 
are  not  correct,  since  the  decrease  in  rotation  with  increase  in 
temperature  is  even  quite  appreciable/  On  account  of  this 

1  As  regards  the  temperature  of  the  wedge-compen»ation  we  are  very  much  in  the 
dark  with  the  present  o.n-tru  tion^,  ;is  tin-  temperature  of  the  rather  thick  wedge 
and  compensation  plates  follows  variations  in  the  room  temperature  very  slowly.  It 
may,  therefore,  be  recomnx  ndcd  t<>  pl:u-<-  the-  coniiirnvation  box  in  ;i  routined  space 
enclosed  by  non-conducting  materials  :md  have  a  tin  rmometer,  graduated  in  whole 
degrees,  extend  into  the  box.  It  is  also  well  to  have  the  light  passing  into  the  apparatus 
and  that  reaching  the  reading  mirror  also  pa^s  through  a  cell  filled  with  water  to 
absorb  the  heat  rays  and  yield  a  cold  light. 

1  See  "  Die  Thiitigkeit  der  physikalisch-technisi-hen  Reichsanstalt  "  under  Scln'in- 
rock,  /Aschr.  fiir  lustrum.,  17,  (1897).  [Hut,  contrary  to  the  statement  in  the  text,  this 
was  previously  accurately  pointed  out  by  Andrews,  Technology  Quarterly,  May,  1889, 
p.  367.  See  also  later,  under  Constants  of  Rotation.  Tr.  J 


SOLEIL-VENTZKE   INSTRUMENT  385 

change  in  specific  rotation  the  rotation  of  the  normal  sugar 
solution  is  decreased  about  — 0.21°  V.  more  by  the  10°  in- 
crease in  temperature.  The  whole  change  then  is  about  — 0.50° 
V.  From  this  it  is  seen  how  necessary  it  is  to  control  the  tem- 
perature in  exact  wprk.  It  must  be  further  noticed  that  the 
errors  due  to  the  wedge-compensation  and  the  sugar  solution 
are  to  be  added  to  each  other,  as  indeed  the  rotation  of  quartz 
increases  while  that  of  sugar  decreases  with  increasing  tem- 
perature, so  that  the  whole  error  of  the  polarization  of  the 
normal  sugar  solution  will  be  0.65°  V.  If  now  it  is  expected 
to  determine  the  loopointofa  saccharimeter  to  within  dzo.o>j°  V. 
by  aid  of  a  normal  sugar  solution,  then,  aside  from  all  other 
sources  of  error,  and  especially  those  in  the  preparation  of  the  so- 
lution (temperature  again  /),  the  temperature  of  the  compensa- 
tion and  of  the  solution  in  the  tube  should  not  differ  from  that  in 
the  definition  of  the  100  point  by  more  than  0.5°  C.  Now,  at 
least,  one  should  be  able  to  recognize  how  difficult  the  gradua- 
tion of  a  saccharimeter  by  aid  of  a  normal  sugar  solution  really 
is.  As  further,  the  mean  adjustment  error  of  the  present  half- 
shadow  instruments  is  only  about  =0.03°  V.,  and  as  these 
saccharimeters  are  used  only  in  technical  work  there  would  be 
no  sense  in  increasing  their  delicacy  still  further,  since,  at  the 
present  time,  polarizations  are  made  with  a  degree  of  accuracy 
which  is  wholly  illusory. 

i.    The  Soleil-  Ventzke  Saccharimeter. 

131.  Description  of  the  Instrument. — In  the  description  of  the 
different  saccharimeters  to  follow,  we  shall  be  very  brief,  since 
it  is  only  necessary  to  add  a  wedge-compensation  to  any  one 
of  the  polarimeters  described  above  to  have  the  corresponding 
saccharimeter.  As  explained,  the  first  saccharimeter  was 
made  by  the  Paris  optician,  Soleil,  and  was  later  improved  by 
Soleil  and  Duboscq.  This  is  the  so-called  color  saccharimeter, 
and  is  shown  in  Fig.  53.  It  may  be  made  by  setting  the  Robi- 
quet  polariscope,  described  in  §100,  at  the  position  of  optical 
equilibrium  and  then  inserting  a  simple  wedge-compensation 
between  polarizer  and  analyzer.  The  light,  therefore,  passes 
the  following  parts  in  going  through  the  apparatus  from  right 
to  left ;  first,  the  regulator  of  the  sensitive  tint  not  described 
25 


386 


SACCHARIMETERS 


above  under  the  head  of  the  Robiqtiet  apparatus,  and  which 
must  be  referred  to  here,  consisting  of  a  nicol,  A,  which  may 
be  rotated,  and  a  right  or  left  quartz-plate,  B,  which  is  ground 
perpendicular  to  the  axis,  the  illuminating  lens  C,  the  polari- 
zer D,  the  Soleil  double  plate  E,  the  wedge-compensation  F, 
the  analyzer  G,  and  the  telescope  H.  As  in  the  Robiquet 
apparatus,  adjustment  is  made  on  the  transition  tint  by  move- 
ment of  the  long  wedge  ;  that  is,  uniform  color  of  the  two 
fields  is  secured.  In  §102,  the  drawback  of  the  Robiquet 
instrument,  that  after  inserting  the  rotating  substance  the 
transition  tint  no  longer  has  the  same  color  observed  in  finding 
the  zero  point,  is  referred  to.  This  fault  appears  in  much  less 


Fig-  53- 

degree  in  the  saccharimeter  because  the  rotation  dispersion  of 
the  active  substance  is  largely  compensated  by  the  quartz 
wedges.  But,  in  order  to  keep  the  shade  of  the  transition  tint 
as  nearly  the  same  as  possible  after  putting  in  the  active  sub- 
stance, even  if  somewhat  colored,  and  in  order  to  give  the 
observer  the  power  of  choosing  the  shade  for  the  transition 
tint,  for  which  the  eye  is  the  most  sensitive,  the  so-called  regu- 
lator has  been  added  to  the  saccharimeter.  The  light  polari- 
zed by  the  nicol  A  passes  into  the  quartz-plate  B  and  suffers 
rotation  dispersion,  and  on  account  of  this,  and  the  relation 
of  the  position  of  A  to  B,  certain  rays  will  not  pass  through 
the  latter,  or  will  pass  with  diminished  intensity.  By  rota- 
ting the  nicol  A,  the  tone  of  the  transition  tint  may,  there- 
fore, be  changed  at  will. 

The  rotation  of  the  tube  which   contains  the  regulator  A  B 


HALF-SHADOW   SACCHARIMETERS  387 

is  accomplished  by  aid  of  a  spur-wheel  and  pinion,  the  latter 
being  worked  by  a  rod  attached  to  the  button  J.  The  brass 
frame  holding  the  large  wedge  may  be  moved  horizontally,  and 
for  this  purpose  is  furnished  with  a  lateral  rack  in  which 
works  a  pinion  wheel  controlled  by  the  button  K.  An  inclined 
mirror,  L,  serves  in  reading  the  Ventzke  scale,  the  image  of  the 
scale  being  thrown  into  the  tube  M  which  contains  a  magni- 
fying lens.  In  the  illustration,  a  screw  is  shown  at  N  by  aid 
of  which  the  analyzer  may  be  turned  and  brought  into  the 
proper  position  with  reference  to  the  polarizer  ;  this  movement 
must  be  made,  however,  only  by  the  instrument-maker  in 
adjusting  the  apparatus,  so  that  the  observer  has  nothing  to 
do  with  the  screw  N.  As  regards  the  use  of  the  instrument, 
reference  is  made  to  §97  and  §102.  The  mean  error  of  a 
reading  is  about  ±0.2°  V. 

As  the  adjustment  to  equality  of  tint  in  the  field  of  view  is 
not  possible  with  color  blindness,  inaccurate  with  deficient 
color  sense,  and  for  most  eyes  much  more  tiresome  than  the 
adjustment  to  uniformity  of  illumination,  the  much  more  sen- 
sitive half-shadow  instruments  have  properly  displaced  the 
color  instruments  completely.  It  is  quite  in  vain  to  attempt  to 
make  the  color  instruments  more  sensitive  by  giving  a  con- 
centric form  to  the  Soleil  double  plate  ;  the  part  of  these  in 
saccharimetry  has  been  played  and  for  good. 

2.  Half- Shadow  Saccharimeters 

132.  Construction  of  the  Instruments. — The  half-shadow  polar- 
iscopes  contain,  always,  an  illuminating  lens,  a  polarizing 
mechanism,  the  analyzer,  and  a  telescope.  In  the  construction 
of  saccharimeters,  the  following  polarizing  arrangements  are 
usually  employed.  The  firm  of  Schmidt  and  Haensch  uses, 
in  general,  the  Jellett  polarizer  (§109)  for  the  saccharimeters 
with  double  field;  the  double  field  Lippich  polarizer  (§114) 
could,  of  course,  be  applied  as  well.  In  the  saccharimeters 
with  triple  field,  the  triple  Lippich  polarizer  is  employed 
(§115).  If,  now,  either  kind  of  polarization  apparatus  is 
adjusted  to  uniform  shadow  on  the  fields  of  view,  and  a  simple 
or  double  wedge-compensation  is  introduced  between  the 
analyzer  and  the  analyzer  diaphragm,  the  corresponding  half- 


388  SACCHARIMETERS 

shadow  saccharimeter  is  produced.  The  light  passes  then 
through  the  following  optical  parts  :  the  illuminating  lens, 
polarizing  mechanism,  wedge-compensation,  analyzer,  and  tel- 
escope. Polarizer  and  analyzer  must  have  a  fixed  position  and 
be  properly  protected  against  any  accidental  displacement,  as 
is  the  case,  for  example,  in  all  the  instruments  made  by  Schmidt 
and  Haensch.  It  must  be  considered  an  error  of  construction 
to  give  a  saccharimeter  a  variable  half-shadow.  The  zero 
point  of  the  instrument  varies  naturally  with  the  half -shadow. 
This  should  be  made  5°  to  8°.  The  mean  error  of  an  adjust- 
ment for  a  saccharimeter  with  double  field  is  about  rb  0.06°  V, 
and  for  the  saccharimeters  with  triple  field,  about  0.03°  V. 

Below  a  very  condensed  description  of  the  commonly  used 
types  of  saccharimeters  will  be  given,  with  especial  considera- 
tion of  the  mechanical  construction. 

133.  Half-Shadow  Saccharimeter  with  Single  Wedge-Compensation 
and  Double  Field  (Schmidt  and  Haensch). — This  apparatus  is  shown 
in  Fig.  54.  The  movable  quartz  wedge  is  mounted  in  a  frame 
.B 


54- 

attached  to  a  lateral  rack  in  which  a  pinion  wheel  controlled 
by  the  button  A  works.  The  reading  of  the  scale  and  ver- 
nier is  accomplished  by  aid  of  the  inclined  mirror  in  B,  and 
lens  in  the  tube  C. 

134.  Half-Shadow  Saccharimeter  with  Double  Wedge-Compensation 
and  Triple  Field  (Schmidt  and  Haensch) — ,in  this  instrument,  shown 
in  Fig.  55,  the  black  set  screw  A  moves  the  working  wedge 
while  the  yellow  screw  B  moves  the  control  wedge,  and  in 
such  a  manner  that  by  aid  of  the  lens  C,  the  working  scale  is 
seen  above  and  the  control  scale  below.  As  regards  the  illu- 
mination of  the  scales  this  is  accomplished  by  means  of  the 


BEET-JUICE    SACCHARIMETER 


339 


mirror   D,  which  is  attached  to  the  ball  and  socket  mechanism 

at  E,  and  which  may  be  so  turned  as  to  receive  light  from  the 

D 


Fig.  55- 

illuminating  lamp  and  throw  it  through  the  matted  upper  sur- 
face of  the  glass  plate  F  on  the  scales.  The  small  screen  G 
serves  to  protect  the  scales  from  outside  lights. 

135.  Beet-juice  Saccharimeter  with  Limited  Enlarged  Scale.1 — This 
instrument,  the  front  part  of  which  is  illustrated  in  Fig.  56, 
was  constructed  by  Schmidt  and  Haensch  from  a  suggestion 
of  Stammer.  It  is  distinguished  from  the  previously  described 
instruments  only  by  its  limited  scale  extending  from  o°  to  35° 
V.  A  reading  of  higher  degrees  is  not  necessary,  since  it  is 
used  only  for  the  determination  of  sugar  in  beets.  In  order 
to  carry  out  the  polarizations  in  such  cases,  where  in  a  short 
time  the  largest  possible  number  of  tests  must  be  made,  and 

1  Stammer  :  Ztschr.  fiir  Riibenzucker-Ind.,  37,  474  (1887).     Schmidt  and  Haensch  : 
Jbid.,  43,  1040  (1893). 


390 


SACCHARIMETERS 


to  avoid  the  delay  of  reading  by  the  telescope,  the  instrument 
is  furnished  with  an  enlarged  scale  which  permits  an  easy 
reading  to  o.  i  of  i  per  cent,  with  the  unaided  eye,  and  even 
at  a  distance.  The  mechanism  consists  of  a  segment  of  a  cir- 
cle attached  in  upright  position  to  the  wedge-compensation, 
and  on  which  the  beet-juice  graduation  of  o°  to  35°  V  is 


Fig.  56- 

marked.  In  the'center  of  the  segment  there  is  a  small  drum, 
R,  which  is  kept  in  position  by  a  spring  ;  this  drum  is  attached 
to  the  movable  wedge  by  a  thin  steel  chain  in  such  a  manner 
that  when  the  wedge  is  moved  to  and  fro  by  the  button  K, 
the  drum  R  is  brought  into  motion,  and  then  the  long  pointer 
joined  to  it  moves  over  the  graduation  of  the  segment.  If  the 
diameter  of  the  drum  bears  a  certain  relation  to  the  length  of 
the  movable  scale,  then  the  circular  segment  graduation  gives 
exactly  the  whole  and  tenths  of  per  cent,  of  the  scale. 

To  secure  accurate  adjustment  the  apparatus  is  brought  to 
the  point  of  half -shadow  uniformity  ;  if  the  scale  then  does 
not  begin  at  o°  a  correction  is  made  by  a  key  to  be  attached 
to  V.  In  this  position  the  pointer  of  the  circular  graduation 
should  stand  at  o°  also  ;  any  necessary  correction  of  this  zero 


PETERS'  HALF-SHADOW  SACCHARIMETER  391 

point  may  be  made  by  a  slight  movement  of  the  small  screw 
fastening  the  chain  to  the  wedge,  which  is  accomplished  by  aid 
of  the  little  set  lever  5".  Any  movement  of  the  wedge  ex- 
pressed in  per  cent,  must  be  exactly  duplicated  on  the  circular 
graduation.  If  this  is  not  the  case  a  correction  is  made  by 
turning  the  nut  attached  to  R  a  little  on  or  off,  which  has  the 
effect  of  slightly  increasing  or  decreasing  the  diameter  of  R, 
and,  therefore,  of  making  the  deflection  of  the  pointer  less  or 
more,  to  correspond.  The  whole  adjustment  must  be  revised 
from  time  to  time. 

136.  The  Half-Shadow  Saccharimeter  of  Peters.1 — This  instru- 
ment, shown  in  Fig.  57,  is  distinguished  from  the  foregoing  in 
several  points  which  will  be  explained.  It  is  a  half- shadow 


Fig.  57- 

saccharimeter  with  Lippich  polarizer  and  double  wedge-com- 
pensation, and  is  supported  on  two  unusually  stable  feet,  which 
prevent  upsetting  the  instrument.  In  the  brass  shell  A, 
there  is  a  wide  glass  tube  with  end  plates,  like  a  polarizing 
tube,  which  may  be  filled  with  a  solution  of  potassium  dichro- 
mate.  The  pointer  at  B  is  used  to  turn  one  of  the  nicols  of 
the  Lippich  polarizer  ;  the  scale  is  placed  below  here  in  order 

1  Peters  (Berlin):  Ztschr.  fur  Riibenzucker-Ind.,  44,  221  (1894). 


392  SACCHARIMETERS 

to  be  able  to  illuminate  the  Yentzke  scale  above  by  mirror  re- 
flection from  the  polarization  lamp.  The  pointer  at  B  is  usually 
left  in  a  fixed  position  and  can  be  moved  only  by  aid  of  a  special 
key.  But  this  possibility  of  regulating  the  half-shadow  is 
without  value  in  a  technical  instrument  and  may  give  rise  to 
serious  errors  ;  for  as  often  as  the  index  B  is  moved  the  ana- 
lyzer must  also  be  turned  to  the  point  of  equal  illumination  of 
the  two  halves  of  the  field  ;  the  technical  saccharimeters  must 
have,  beyond  question,  a  fixed  half-shadow.  The  apparatus 
has  no  lid  at  C,  but  closing  is  effected,  after  laying  in  the  ob- 
servation tube,  by  rotating  a  movable,  half-open  shell.  The 
final  adjustment  screws  are  extended  by  means  of  universal 
joints  so  as  to  reach  nearly  to  the  table  on  which  the  apparatus 
rests,  which  makes  it  possible  to  move  the  compensation  with- 
out lifting  the  arms.  The  screw  D,  which  works  the  right 
scale,  is  placed  somewhat  lower  than  E,  which  turns  the  left 
one,  so  as  to  avoid  possibility  of  confusion. 

137.  Half-Shadow  Saccharimeter  of  Josef-Jan  Fric.1 — This  instru- 
ment with  double  wedge-compensation,  the  front  partof  which  is 
shown  in  Fig.  58, is  distinguished  from  the  ordinary  constructions 
in  this  that  each  one  of  the  two  scales  is  read  by  a  special  lens  and 


Kig.  58.  I'M*.  59- 

1  Joseph-Jan  Fric  (Prague):  Oesterr-Ungar.  Ztschr.  fiir  Zuckerindustrie,  V. 
Heft  (1895).  E.  H.  Sargent  &  Co.,  Chicago,  are  the  American  agents  for  these  new 
instruments. 


GAS    LAMPS 


393 


illuminated  separately  by  a  new  and  excellent  arrangement, 
the  details  of  which  are  shown  in  Fig.  59  diagrammatically. 
The  light  coming  from  the  regular  illumination  lamp  is  re- 
flected by  the  movable  mirror  A  and  passes  through  the 
milk-glass  plate  B  upon  the  scale  C,  the  surface  of  which 
is  so  inclined  toward  the  mirror  D,  that  the  light  reach- 
ing the  latter  is  thrown  in  the  direction  of  the  optical  axis 
of  the  telescope  E.  The  so  illuminated  metallic  scale  C  ap- 
pears on  account  of  the  diffuse  light  from  the  milk-glass 
plate,  as  distinct  as  the  old  ivory  scales.  The  left  telescope 
with  black  mountings  reads  the  working  scale,  while  the  right 
one  with  red  mountings  reads  the  control  scale.  Besides  this, 
the  control  scale  is  seen  by  red  light,  since  the  milk-glass 
plate  in  this  case  is  replaced  by  a  plate  of  red  glass,  to  exclude 
possibility  of  mistake  in  reading. 

c.   Illuminating  Lamps. 

i.   Lamps  for  White  Light. 

138.  Schmidt  and  Haensch  Gas 
Lamps. — Great  importance  need 
not  be  attached  to  perfect  uni- 
formity in  illumination  as  long 
as  a  correct  passage  of  the  rays 
through  the  apparatus  is  provi- 
ded for  according  to  §96  and 
§129.  Changes  in  the  intensity 
of  the  light  bring  about  no 
changes,  then,  in  the  zero  point, 
and  it  is  immaterial  whether  we 
use  a  flat  burner  or  a  round  one. 
A  very  convenient  form  of  lamp 
is  shown  in  Fig.  60,  which  em- 
ploys gas,  and  is  furnished  with  a 
triple  flat  burner,  metallic  chim- 
ney and  a  reflector.  As  these 
gas  and  petroleum  lamps  are  usu- 
ally still  furnished  writh  a  so- 
called  condensing  lens  which,  as  a 
matter  of  fact,  has  no  importance,1 

1  The  lens  does  not  increase  the  intensity 
feres  with  the  correct  passage  of  the  rays. 


Fig.  60. 
of  the  illumination,  and  always  inter- 


394  ILLUMINATING    LAMPS 

in  ordering  a  lamp  one  should  be  careful  to  secure  a  form 
which  has  in  place  of  this  lens  a  clear  glass  plate. 

139.  The  Hinks  Petroleum  Lamp. — For  use  with  petroleum,  the 

Hinks  duplex  lamp  with  metallic 
chimney,  shown  in  Fig.  61,  has 
given  excellent  satisfaction.  Before 
lighting  the  lamp,  the  precaution 
must  be  taken  to  see  that  the  cap 
used  to  extinguish-  the  flame  is 
shoved  back  into  its  proper  place,  by 
aid  of  the  lever  on  one  side  of  the 
burner,  so  as  to  leave  the  wick  per- 
fectly free  to  burn  evenly. 

140.  Lamps  with  the  Welsbach  Incan- 
descent Gas  Light — On  account  of 
their  intense  light  these  can  be 
strongly  recommended  for  the  illu- 
mination of  saccharimeters.  For 
this  purpose  the  ordinary  lamp  with 
glass  chimney  is  furnished  with  a 
second  outer  chimney  of  porcelain  or 
asbestos,  which  at  the  proper  point 
is  provided  with  a  suitably  large 
opening  to  permit  the  passage  of  the 
light.  The  polariscope  is  naturally 

directed  toward  the  brightest  part  of  the  glowing  substance. 
It  is  not  at  all  necessary  to  use  a  ground-glass  chimney,  as, 
with  proper  distance  between  lamp  and  instrument  (§129),  the 
meshes  of  the  mantle  do  not  disturb  in  the  slightest  degree, 
since,  in  fact,  the  image  of  the  glowing  body  produced  by  the 
illumination  lens  is  formed  at  the  analyzer  diaphragm. 

141.  Lamp  for  Electric  Light. — This  consists  of  a  stand  with 
the  necessary  connecting  wires  on  which  a  very  strong  incan- 
descent lamp  (of  about  50  Hefner  units  with  100  to  no  volts) 
can  be  moved  in  vertical  direction.     The  metallic  cylinder  sur- 
rounding the  globe  has  anjopening  in  the  right  place  to  allow 
the  best  part  of  the  light  to  pass. 

142.  Zirconium  Light. — The  zirconium  light  is,   by   far,  the 


GAS   LAMPS 


395 


most  intense  white  light.  To  produce  it  a  Linnemann  burner 
fed  by  oxygen  and  illuminating  gas  is  used,  the  hottest  part 
of  the  flame  being  directed  against  a  plate  of  zirconia  in  a 
platinum  support.1  Instead  of  a  zirconia  plate  a  cylinder 
of  the  same  substance  may  be  used.2  It  is  most  advantageous 
to  place  the  burner  in  a  large  sheet-iron  box  provided  with 
windows,  a  door,  and  an  inclined  chimney.  The  lime  light 
burners,  fed  by  illuminating  gas  and  oxygen,  may  also  be 
strongly  recommended.3 

2.  Lamps  for  Homogeneous  Light 

143.  Simple  Sodium  Flame  Gas-Lamps.4 — In  order  to  secure  a 
sodium  flame  of  considerable  dura- 
tion, the  lamp  illustrated  in  Fig.  62 
may  be  used.  This  consists  of  a  Bun- 
sen  burner  which  may  be  adjusted  in 
vertical  position,  over  which  a  me- 
tallic chimney  is  placed.  The  gas 
entrance,  s,  is  found  at  one  side 
where  it  will  not  become  clogged  by 
bits  of  salt  dropping  from  the  flame. 
The  chimney  may  be  adjusted  by 
aid  of  the  screw  h  at  the  proper 
height.  At  the  top  of  the  column, 
/>,  which  may  be  rotated,  a  rod  is  at- 
tached horizontally  wThich  carries 
at  its  end  a  bundle  of  fine  platinum 
wires.  These  are  so  bent  that  they 
form  a  little  pointed  spoon.  If  this 
is  filled  with  well  dried  salt  and 
turned  so  as  to  rest  in  the  front  side 
of  the  flame,  the  melted  salt  is  drawn  ^j  If 
up  into  the  point  of  the  spoon  andl^ 
produces  an  intense  yellow  light  on 
volatilization.  By  aid  of  the  sheet 
metal  shutter  k,  which  has  an  opening,  the  light  from  the 

1  lyinnemann  :  "  Ueber    ein    neues   Iveuchtgas-Sauerstoffgeblaesse  und  das    Zir- 
konlicht,"  Wiener  Sitzungsberichte  II,  92,  1248  (1885). 
-  From  M.  Wolz,  in  Bonn. 

3  From  Meckel,  Kaiserstrasse  32,  Berlin. 

4  From  Schmidt  and  Haensch,  Berlin. 


Fig.  62. 


396 


ILLUMINATING   LAMPS 


brightest  part  of  the  flame  only   may   be   allowed   to   pass. 
A  second  sodium  lamp,  which  is  very  muchrlike  the  first, 

is  shown  in  Fig.  63  ;  the 
application  will  be  read- 
ily understood.  Instead 
of  salt,  well  calcined  so- 
dium carbonate  may  be 
used  in  these  lamps ;  the 
volatilization  is  slower, 
but  the  intensity  of  the 
light,  at  the  same  time, 
less. 

144.  Pribram's  Sodium 
Lamp.1 — If  it  is  necessary 
to  work  a  long  time  with 
constant  illumination, 
the  Pribram  lamp,  shown 
in  Figs.  64  and  65,  is 
found  useful.  The  gas 
led  in  at  a  emerges 
through  the  fine  open- 
ings at  b  and  mixes  in 
the  burner  top  c  with  the 
air  which  enters  at  d,  the 
flow  of  which  may  be  reg- 
ulated by  turning  a  per- 
::.  forated  disk  by  aid  of  the 
lever  k.  The  gas  is  ig- 
nited at  the  gauze  top  of 
the  burner  at  e.  The 
chimney  b,  which  is  lined 
with  asbestos,  has  four  openings,  through  one  of  which,  m,  the 
light  reaches  the  polariscope,  while  a  second  one,  i,  is  furnished 
with  a  cap  and  serves  for  igniting  and  observing  the  flame. 
At  g  and  h  two  little  platinum  boats,  which  are  filled  with 
fused  salt,  may  be  introduced  into  the  flame. 

i  Pribram  :  "  l>l>er  einen  neuen  Brenner  fur  Natriumlicht,"  Ztschr.  anal.  Chem., 
34,  166  (1895),  made  by  Schmidt  and  Haensch. 


Fig-  63. 


LAXDOLT'S   SODIUM    LAMP 


397 


-g 


Fig.  64. 


Fig.  65. 


145.  Landolt's  Sodium  Lamp.1 — A  much  stronger  sodium  light 
than  that  furnished  by  the  burners  described  may  be  secured  by 
the  lamp  shown  in  Fig.  66.  A  Muencke  burner  (Bunsen  lamp 
with  conical  wire  gauze  top  and  so  strong  an  air  supply  that 
the  inner  dark  cone  of  the  flame  disappears)  is  supported  on 
an  iron  stand,  the  upright  rod  of  which  carries  a  square  chim- 
ney, B,  made  of  sheet  iron.  The  front  side  of  this  chimney 
has  a  round  opening,  over  w?hich  the  plate  C,  with  three  holes 
of  20,  15,  and  10  mm.  diameter,  may  be  shoved.  Two  nickel 
wires,  D,  are  laid  across  the  sheet  metal  cylinder  at  the  top  of 
the  lamp  A,  resting  in  notches  in  the  cylinder,  and  around 
the  middle  of  these  wires  pieces  of  nickel  gauze  are  rolled. 
The  meshes  of  this  gauze  are  filled  with  salt,  and  most  easily, 
as  shown  in  Fig.  67,  by  laying  them  in  a  little  trough  of  nickel 
foil  in  which  the  salt  has  been  previously  melted  by  aid  of  two 
Terquem  burners.  By  placing  the  cylinder  of  the  Muencke 
burner  low,  so  that  the  salt  is  just  over  the  wire  gauze  cone  of 
the  lamp,  a  very  intense  color  is  produced  at  the  front  and  back 
of  the  flame. 

1  I^andolt:  "Xatriumlampe  fur  Polarisationsapparate,"  Ztschr.  fur  Instrurr.,  4,390 
,  made  by  Muencke,  Berlin. 


398 


ILLUMINATING   LAMPS 


Fig.  66. 

If  instead  of  common  salt 


Fig.  67. 

dried  sodium  bromide  is  used, 


following  the  suggestion  of  Fleischl  v.  Marxow,1  a  very  much 
more  intense  light  is  secured  ;  but  the  sodium  bromide  volatil- 
izes much  more  rapidly  than  the  chloride  and  bromine  vapors 
escape  from  the  flame.  In  working  with  sodium  bromide  one 
must,  therefore,  place  the  burner  under  a  good  draft,  as 
otherwise  the  polariscope  may  be  completely  ruined  by  the 
bromine  vapors. 

146.  Intense  Sodium  Light. — A  very  high  illuminating  power 
is  found  in  the  pencils  suggested  by  du  Bois,2  consisting  of 
sodium  bicarbonate  and  sodium  bromide  in  gum  tragacanth, 
heated  in  the  Linnemann  oxygen  blast-lamp.  As  these  pen- 
cils give  out  bromine  vapors,  a  good  draft  must  be  provided. 
Besides  this,  the  greatly  increased  illuminating  power  calls 
for  a  great  consumption  of  material,  so  that  a  rod  about  4  mm. 
thick  and  14  cm.  long  is  completely  burned  in  about  ten  min- 
utes. If  one  wishes,  therefore,  to  work  with  these  pencils,  it 
is  necessary  to  have  an  assistant  or  a  clock-work  mechanism 
to  continually  regulate  the  flame.  These  drawbacks  are 
avoided  by  using,  according  to  Gumlich,3  rods  of  fused  sodium 

1  Fleischl  v.  Marxow  :  Wied.  Ann.,  38,  675  (1889). 

2  I)u  Bois  :  Ztschr.  fiir  lustrum.,  12,  165  (1892). 
8  Gumlich:  /bid.,  16,  in  (1896). 


PURIFICATION  OF  THE  SODIUM  LIGHT  399 

carbonate  about  6  mm.  thick  and  15  cm.  long  in  the  Linne- 
mann  oxygen  blast-lamp.  No  objectionable  vapors  are  pro- 
duced, and  the  rods  burn  so  slowly  that  in  a  period  of  about 
seven  minutes  it  is  usually  not  necessary  to  change  their 
position.  Although  the  intensity  of  the  light  produced  is  not 
quite  equal  to  that  frDrn  the  du  Bois  pencils,  it  is  quite  suffi- 
cient for  nearly  all  purposes  in  polarimetry.  As,  furthermore, 
the  use  of  these  soda  pencils  is  quite  cleanly,  the  volatilization 
of  fused  rods  in  the  oxygen  lamp  may  be  strongly  recom- 
mended. 

j.   Purification  of  the  Sodium  Light.       Optical  Center  of  Gravity 

147.  Lippich's  Sodium  Light-Filter.1 — In  the  following  considera- 
tions, in  order  to  have  a  specific  kind  of  instrument  in  mind, 
we  shall  assume  that  all  observations  are  made  with  a  Lippich 
half-shadow  apparatus  with  double  or  triple  field.  As  the 
following  paragraphs  will  take  up  also  the  comparison  of 
polarimetric  measurements,  it  may  be  remarked  at  the  outset 
that  the  discussion  can  not  be  a  complete  one,  because,  in  the 
first  place,  the  limits  of  the  book  would  not  justify  it,  and, 
secondly,  because  in  many  cases  it  would  not  be  possible  to 
verify  theoretical  considerations  by  experimental  data  avail- 
able. 

Assume  a  substance  having  the  power  of  rotating  the  plane 
of  polarization  and  kept  under  constant  conditions.  It  will 
then  rotate  lights  of  all  wave-lengths  through  definite  angles, 
depending  only  on  these  wave-lengths  Let  the  rotation  /? 
correspond  to  the  perfectly  homogeneous  light  of  wave-length 
A..  Now,  suppose  the  apparatus  illuminated  by  mixed  light 
made  up  of  light  of  wave-length  \  and  light  of  wave-length 
A.,.  Let  Aj  be  smaller  than  A,  and  A.2  greater  than  A.,  but  so 
nearly  the  same  that  the  eye  may  not  recognize  the  difference 
in  shade  between  them.  Notwithstanding  the  consequent 
rotation  dispersion,  it  will  then  be  possible  to  find  the  angle 
of  rotation  fil  of  the  substance  for  this  mixed  light,  as  well  as 
if  the  instrument  were  illuminated  with  perfectly  homogeneous 
light.  The  same  angle  of  rotation,  /?,,  would  be 'found  by 
using  for  illumination,  a  perfect^  homogeneous  light  of  wave- 

1  Lippich  :  Ztschr.  fur  Instrum.,  12,  340  (1892). 


400  SODIUM    LIGHT 

length  A3.  //  may  be  snid,  therefore,  that  for  polarimetric  meas- 
urements, \  is  the  optical  center  oj  gravity  of  the  mixed  lights 
of  wave-lengths  \^  and  A2/  that  is,  if  this  mixed  light  be  em- 
ployed, rotations  are  obtained  which  actually  correspond  to  the 
wave-length  A3.  As  all  polarimetric  measurements  depend 
finally  on  comparisons  of  brightness,  it  may  be  recognized 
directly  that  the  optical  center  of  gravity  A3,  depends  not  only 
on  the  wave-lengths  A.t  and  A2  but  on  the  intensities  of  the  two 
homogeneous  components.  For  a  definite  condition  of  bright- 
ness in  the  two  components  we  have,  for  example,.  A3  —  A.  and 
consequently  $  —  ft  ;  if  now,  the  brightness  of  the  component 
Aj  increases,  then  the  optical  center  of  gravity  Ag  will 
approach  Aj  from  A.  //  may  be  now  shown  that  the  optical 
center  of  gravity  A3  depends  simply  and  alone  on  the  wave- 
lengths and  degrees  of  brightness  of  the  two  homogeneous  com- 
ponents in  the  source  of  light,  and  not  on  the  rotation  dispersion 
of  the  investigated  substances,  or  on  the  amount  of  the  angle 
of  rotation  or  the  size  of  the  half -shadow  angle  chosen,  as  long  as 
the  observations  are  made  with  the  Lippich  apparatus,  and  the 
absorbing  power  of  the  substance  is  relatively  the  same  for  the  two 
components.  In  investigating  substances  with  considerable 
color,  care  must  be  taken  to  see  that  this  last  condition  is  ful- 
filled ;  in  what  follows,  uniform  absorption  is  assumed. 

If  we  pass  now  to  the  general  case,  that  is,  if  we  assume 
that  the  source  of  light  furnishes  light  of  all  wave-lengths, 
then,  for  polarimetric  purposes,  a  definite  optical  center  of 
gravity  will  correspond  to  this  light  also,  as  long  as  the  field  of 
view  possesses  the  same  color  when  the  point  of  optical  equilib- 
rium is  found  with  the  observed  substance  in  position,  as  it  had 
at  the  time  of  the  zero-point  determination.  If  this  is  not  the 
case,  then  the  optical  center  of  gravity  depends  on  the  color 
sense  of  the  observer,  and  the  adjustment  for  reading  becomes 
more  and  more  inaccurate  with  increasing  difference  in  color. 
With  constant  color ,  it  may  be  shown,  as  before,  that  the  optical 
center  of  gravity  of  the  source  of  light  depends  simply  and  alone 
on  the  relative  distribution  of  intensity  in  the  spectrum  of  the 
source  of  light,  as  long  as  the  absorption  of  the  active  substance 
is  relatively  the  same  for  all  wave-lengths  in  the  light  in  ques- 
tion. We  have  then  this  important  result,  that  under  the 


PURIFICATION  OF  THE  SODIUM  LIGHT  401 

assumed  conditions,  a  definite  optical  center  of  gravity  corresponds 
to  any  given  source  of  light,  which  is  the  same  for  all  Lippich 
instruments.  Of  course,  other  sources  of  light  which  show  the 
same  relative  brightness  in  their  spectra,  have  the  same  optical 
center  of  gravity.  If  the  light  is  purified  by  passing  through 
light  filters,  the  real  source  of  light  must  now  be  taken  as  that 
corresponding  to  the  new  optical  center  of  gravity.  In  what 
follows  the  optical  center  of  gravity  will  be  given  for  the 
sources  of  light  mentioned,  as  far  as  this  is  possible  with  the 
present  meagre  and  inaccurate  determinations. 

We  shall  consider  first  the  most  commonly  used  homogene- 
ous light,  the  sodium  light.  Every  source  of  sodium  light 
gives  a  continuous  spectrum,  in  which,  however,  the  light  of 
the  sodium  lines  is  enormously  in  excess.  If  now7,  smaller 
rotations  are  measured  with  the  unpurified  sodium  light,  the 
rather  dark  field  of  view  will  disclose  no  color.  But  as  soon 
as  large  angles  of  rotation  are  to  be  measured  the  field  of  view 
appears  distinctly  colored  and  the  sodium  light  must  be  puri- 
fied from  foreign  rays.  The  color  of  the  field  depends  on  the 
rotation  dispersion  of  the  active  substance.  As  the  analyzer 
is  always  so  placed  that  the  yellow  sodium  light  is  nearly  ex- 
tinguished, it  follows  that  with  large  rotations  the  blue  rays, 
for  example,  wrhich  are  much  more  strongly  rotated  than  the 
yellow,  are  able  to  pass  through  the  analyzer  but  little  weak- 
ened and,  therefore,  impart  a  blue  color  to  the  field  of  view.  The 
shade  depends  on  the  rotation  dispersion  of  the  active  sub- 
stance, and  the  amount  of  the  angle  of  rotation.  In  the  course 
of  time  a  large  number  of  absorbing  substances  have  been  sug- 
gested to  purify  the  sodium  light,1  of  which,  up  to  the  present, 
the  Lippich  sodium  light  filter  is  the  best,  if  for  the  moment 
we  leave  the  complete  spectral  purification  out  of  consideration  ; 
therefore  this  Lippich  light  filter  only  will  be  specially  de- 
scribed. 

The  Lippich  sodium  light  filter  is  an  absorption  cell  consist- 
ing of  two  chambers  which  the  light  passes  in  succession,  and 
which  are  closed  by  plane  plates.2  The  larger  of  the  two 
chambers  has  a  length  of  10  cm.,  the  smaller  a  length  of  1.5 
cm.  The  large  chamber  is  filled  with  a  filtered  6  per  cent,  so- 

1  The  light  filters  must  be  placed  between  the  lamp  and  the  illumination  lens. 

2  It  is  made  by  Schmidt  and  Haensch,  Berlin. 
26 


402  SODIUM    UGHT 

lution  of  potassium  dichromate,  in  water.  In  the  smaller  cell 
there  is  a  solution  of  uranous  sulphate,  US2O8.  This  is  deep 
green  and  must  be  made  by  reduction  of  the  corresponding 
uranyl  salt,  USO6.  As  the  uranous  salt  solution  passes  into 
the  other  by  oxidation  in  the  air,  a  perfectly  air-tight  cell  must 
be  provided,  and  the  solution  must  be  renewed  from  time  to 
time.  The  uranous  sulphate  solution  is  made  as  follows  :  5 
grams  of  pure  uranic  sulphate  is  dissolved  in  100  cc.  of  water 
and  2  grams  of  pure  zinc  in  powdered  form  added.  Then  3 
cc.  of  concentrated  sulphuric  acid  is  added  in  three  portions, 
waiting  after  each  addition  until  the  reaction  is  nearly  com- 
plete ;  the  flask  must  remain  closed.  After  the  addition  of  the 
last  portion  of  acid  the  closed  flask  is  allowed  to  stand  about 
six  hours ;  the  liquid  is  then  filtered  and  filled  into  the  cham- 
ber in  such  a  manner  as  to  leave  the  smallest  possible  air  bub- 
ble. After  a  day  the  solution  comes  to  rest  and  remains  one 
or  two  months  constant.  The  weights  and  volumes  given 
above  must  be  adhered  to  within  llloo  °f  their  amounts.  While 
the  potassium  dichromate  absorbs  a  part  of  the  green  rays  and 
the  blue  rays,  the  uranous  sulphate  solution  ha!s  a  wide  and 
deep  absorption  band  in  the  red  which  reaches  nearly  to  the 
D  lines.  A  spectrum  is,  therefore,  obtained  in  which  only  a 
small  band  with  the  D  lines  in  the  middle  is  present.  The 
two  solutions  produce  so  complete  a  purification  of  the  sodium 
light  that  even  with  a  rotation  of  50°  and  a  strong  illumina- 
tion, difference  in  color- is  scarcely  perceptible.  It  is,  therefore, 
desirable  that  chemists  in  general  should  employ  this  L,ippich 
filter  for  the  purification  of  sodium  light,  and  especially  for  the 
reason  that  thereby  the  results  of  different  observers  would  be 
comparable  among  themselves. 

148.  Optical  Center  of  Gravity  of  Sodium  Light. — Completely  pu- 
rified sodium  light  consists  of  the  light  of  the  two  D  lines  and 
extremely  little  light  of  adjoining  wave-lengths.  Following 
Bell1  we  shall  take  the  wave-length  of  the  less  refrangible  so- 
dium line  Dp  as  589.62  /^,  and  of  the  more  strongly  refrangi- 
ble one  D2,  as  589.02  ////.  In  close  agreement  the  observa- 
tions of  Soret  and  Sarasin,"  and  of  Lippiclv'  have  shown  that 

»  Bell :  Phil.  Mag.  [5]  35,  245,  350  (1888). 

8  Soret  and  Sarasin:  Compt.  rend.,  95,  635  (1882). 

8  I^ippich:  Wiener  Sitzungsber,  II,  99,  722  (1890). 


CENTER  OF  GRAVITY  OF  SODIUM  LIGHT  403 

for  a  quartz  plate  i  mm.  in  thickness  the  difference  in  rotation 
of  the  two  D  lines  corresponding  to  the  0.60  n/J  is  about  i6o".1 
Therefore  a  difference  in  rotation  for  i  mm.  of  quartz,  J  ft, 
corresponding  to  a  change,  J  A,  in  the  wave-length  in  the 
neighborhood  of  the  D  lines  may  be  calculated  from  the  equa- 
tion, J  yff/J  \  =  —266  \  ^  sec\  If,  therefore,  we  determine 
L  ;ujw  J 

as  Lippich  did,  the  rotation  /?  of  a  quartz  plate  for  homogene- 
ous light  of  wave-length  A  ==  D2,  for  example,  and  then  the 
rotation  /?,,  for  an}'  other  sodium  light,  we  are  able  in  the  sim- 
plest manner,  by  aid  of  the  above  equation,  to  calculate  the 
optical  center  of  gravity  corresponding  to  /3im  But  this  optical 
center  of  gravity  is  not  peculiar  to  the  quartz  alone,  but  it 
holds  good  for  all  substances,  since,  as  was  explained  in  the 
last  paragraph,  the  optical  center  of  gravity  of  a  source  of 
light  is  independent  of  the  rotation  dispersion  and  of  the  size 
of  the  angle  of  rotation.  It  is,  therefore,  possible  to  find,  with 
the  aid  of  a  quartz  plate,  the  optical  center  of  gravity  of  the 
different  kinds  of  sodium  light. 

We  ma}r  now  calculate  this  optical  center  of  gravity  for  per- 
fectly purified  sodium  light,  and  it  may  be  assumed  that  it 
contains  only  the  light  of  the  two  D  lines.  According  to  Die- 
trich2 the  relation  of  the  intensities  of  the  two  lines  is  D2/D1  = 
1.6.  By  aid  of  this  value  and  the  wave-lengths  given  above 
for  the  D  lines  the  optical  center  of  gravity  of  the  fully  puri- 
fied sodium  light  is  found  to  be  589.25  ///*  ;  the  method  of  cal- 
culation need  not  be  discussed  here.  Lippich  has  experi- 
mentally determined  the  optical  center  of  gravity  for  several 
sodium  lights  ;3  the  wave-lengths  of  the  center  given  in  the 
table  below  differ  from  those  stated  by  Lippich  in  the  paper 
cited,  by  a  constant  difference,  because  he  assumes  a  wave- 
length for  D.2  different  from  that  we  have  taken  above.  Finally, 
it  is  possible  to  calculate  from  some  observations  of  Landolt* 
the  optical  center  of  gravity  of  unpurified  sodium  light  (Lan- 
dolt sodium  lamp  with  NaCl)  as  588.06  /*/*.  In  the  following 
table  the  determined  optical  centers  are  grouped  for  comparison. 

1  About  the  same  value  is  given  by  the  Boltzmann  dispersion  formula  for  quartz. 

-  Dietrich  :  Wied.  Ann.,  12,  519  (1881). 

3  Lippich:  Ztschr.  fur  Instrum.,  12,  333  (1892). 

•*  I^andolt:  Ber.  d.  chem.  Ges.,  27,  2885  (1894). 


404 


SODIUM    LIGHT 


OPTICAL  CENTERS  OF  GRAVITY  OF  SODIUM  LIGHT,  ASSUMING 
589.02  /x/x  AS  THE  WAVE-LENGTH  OF  D2. 


No. 

Source  of  Light. 

Purification. 

Wave- 
lengths 
in  MM- 

I 

Bunsen  burner 
with  NaBr 

Layer  of  a  9  per  cent,  aqueous  solu- 
tion of  K2Cr2O7  10  cm.  thick 

592.04 

2 

Bunsen  burner 
with  NaCl 

Layer  of  a  9  per  cent,  aqueous  solu- 
tion of  K2Cr.2O7  10  cm.  thick 

589.48 

3 

Bunsen  burner 
with  NaCl  or  NaBr 

Lippich's  sodium  light  filter, 
K2Cr2O-  and  US2O, 

589-32' 

4 

Sodium  light 

Perfectly  purified  spectrum  light. 
The  two  D  lines  only 

589-25 

5 

Landolt's  sodium 
lamp  with  NaCl 

Layer  of  a  6  per  cent,  aqueous  solu- 
tion of  K2Cr2O-   1.5  cm.  thick 

588.94 

6 

Bunsen  burner 
with  NaCl 

Layer  of  a  9  per  cent,  aqueous  solu- 
tion of  K2Cr2O7  10  cm.  thick,  and 
layer  of  a  13.  6  per  cent,  aqueous 
solution  of  CuCl2  i  cm.  thick2 

588.91 

7 

Landolt's  sodium 
lamp  with  NaCl 

Not  purified 

588.06 

It  must  be  again  remarked  that  these  optical  centers  of 
gravity  are  exact  only  when  the  active  substances  under  in- 
vestigation do  not  appreciably  alter  the  distribution  of  the 
intensity  of  the  light  from  the  source  employed.  If,  in  illus- 
tration, the  rotation  of  a  quartz  plate  is  found  to  be  20°  with 
light  No.  i,  the  same  plate  will  show  a  rotation  of  20.27°  with 
light  No.  7  ;  the  difference  amounts  to  16.2  minutes  of  arc, 
certainly  a  considerable  amount.  It  is  plain,  therefore,  how 
important  it  is  in  statements  of  rotations  for  sodium  light  to 
give  at  the  same  time  the  optical  center  of  gravity  of  the  light 

1  The  optical  center  of  gravity  is  therefore  found  midway  between  the  two  D  lines 
and  it  is  further  seen  that,  after  purification  with  the  Lippich  filter,  even   large  varia- 
tions in  the  intensity  of  the  sodium  light  do  not  appreciably  affect  the  optical  center 
of  gravity. 

2  One  gram  of  cupric  chloride  to  6.35  cc.  of  water. 


SPECTRAL  PURIFICATION  OF  SODIUM  LIGHT  405 

used,  as  otherwise  the  rotations  are  uncertain  to  the  extent  of 
i  per  cent,  or  more.  If  we  consider,  foi  example,  the  results 
which  the  different  observers  found  in  the  determination  of 
the  Verdet  constant  for  the  electromagnetic  rotation  of  the  plane 
of  polarization,  it  is  evident  that  the  measurements  of  these 
different  observers  are  not  directly  comparable  with  each  other.1 
Nearly  every  one  of  the  seven  observers  employed  a  dif- 
ferent source  of  sodium  light  and  method  of  purification,  and 
besides  this,  several  values  have  even  been  found  with  the 
Laurent  half-shadow  instrument  (see  §113)  ;  furthermore, 
the  electromagnetic  rotation  dispersion  for  carbon  disulphide 
and  water  is  somewhat  greater  than  the  natural  rotation  dis- 
persion of  quartz. 

149.  Spectral  Purification  of  Sodium  Light." — In  very  exact  work 
physicists  wrill  always  prefer  spectral  purification  of  light  to 
that  by  means  of  filters.  The  spectral  purification  has  always 
this  great  advantage  over  the  filter  method,  that  it  permits  the 
yellow  rays  to  pass  undiminished  into  the  instruments  while  in 
the  light  filters,  a  certain  amount  of  the  light  is  always 


B 
A 

Fig. 

absorbed.  For  the  purpose  of  spectral  purification,  it  is  not 
recommended  to  use  the  Wernicke  liquid  prism,  because,  in 
consequence  of  the  heating  effect,  the  course  of  the  rays  is 
subject  to  constant  changes  ;  it  is  much  better  to  use  glass 
prisms.  The  following  method  of  spectral  purification  of 
sodium  light  has  been  found  by  the  author  through  long  ex- 

1  A  tabular  compilation  of  all  the  absolute  determinations  is  found  in  Ztschr. 
fur  lustrum.,  16,283  (1896).  Notice,  especially,  the  almost  impossible  accuracy  with 
which  several  observers  claim  to  have  established  the  value. 

-  See,  also,  Brodhun  and  Schonrock  :  Ztschr.  fur  Instrum  ,  16,  244  (1896). 


406  SODIUM   LIGHT 

perience  to  work  well  ;  it  may  be  used  also  in  the  purification 
of  any  other  homogeneous  light.  By  aid  of  the  lens  B  (Fig. 
68),  a  sharp  image  of  the  source  of  light  A  is  thrown  on  the 
slit-screen  C.  The  light  which  passes  through  the  slit  falls 
on  the  achromatic  lens  D  and  is  then  decomposed  by  the  flint 
glass  prism  E,  placed  in  position  of  minimum  deviation.  A 
sharp  image  of  the  luminous  slit  C,  with  the  spectrum,  is 
thrown  on  the  second  slit-screen  G  by  the  lens  D.  In  order 
to  secure  the  greatest  possible  dispersion,  the  distance  between 
D  and  G  is  taken  rather  great,  say  2  to  3  meters.  The  rays 
are  then  sufficiently  parallel  in  passing  the  prism  E.  Just  in 
front  of  the  slit  G  there  is  a  lens  F,  which  produces  a  sharp 
image  of  the  lens  D  on  the  illuminating  lens  H  of  the  Lippich 
apparatus.  The  slit  G,  which  passes  the  purified  sodium  light, 
must  naturally  have  such  a  position  with  reference  to  the  lens 
H  that  the  latter  will  produce  a  clear  image  of  G  at  the 
analyzer  diaphragm.  As  D  is  pictured  at  H,  it  follows  that 
the  former  must  be  uniformly  illuminated  by  the  slit  C,  which 
however  may  be  accomplished  without  difficulty.  Aside  from 
reflexions,  there  is,  therefore,  no  loss  of  light  on  the  way 
from  C  to  H.  The  active  sections  of  the  lens  D  and  prism  E 
must  be  chosen  large  enough,  so  that  the  polarizer  diaphragm 
will  be  quite  filled  with  light.  The  width  of  the  slit  G  is,  of 
course,  made  only  as  great  as  required  by  the  analyzer 
diaphragm  and  focal  length  of  the  illumination  lens  H  in  order 
to  secure  maximum  brightness  in  the  field  of  view  ;  and, 
accordingly,  the  slit  C  is  made  so  narrow  that  its  enlarged 
image  formed  by  the  sodium  rays  is  just  sufficient  to  fill  the 
slit  G.  As  regards  the  centering  of  the  course  of  the  rays,  it 
may  be  remarked  that  we  begin  with  H  and  place  G,  then  F, 
and  the  following  pieces  in  position.  Of  course,  the  pieces 
from  B  to  G  need  not  be  united  in  one  apparatus  ;  it  is  better 
to  have  them  attached  to  small  stands  which  may  be  moved 
into  the  right  positions  and  then  made  fast  to  the  table  with 
wax.  Although  the  light  rays,  if  the  dispersion  is  sufficiently 
great,  must  pass  through  a  distance  of  5  or  6  meters  from 
the  source  of  light  to  the  eye  of  the  observer,  it  is  still  pos- 
sible to  build  up  the  whole  apparatus  in  a  rather  small  room  if 
a  plane  mirror  is  placed  in  the  prolongation  of  the  axis  of  the 


BRIGHTNESS  OF  THE  LIGHT 


407 


apparatus  between  E  and  F.  The  pieces  from  A  to  E  can  then 
be  built  up  parallel  to  the  apparatus  and  but  slightly  removed 
from  it,  and  the  sodium  light  thrown  into  the  instrument  by 
aid  of  the  mirror.  The  spectral  purification  of  the  light  se- 
cured by  this  method  is  so  perfect  that  even  with  an  angle 
of  rotation  of  500°,  the  slightest  color  in  the  field  of  view  is 
not  apparent. 

150.  Dependence  of  the  Optical  Center  of  Gravity  on  the  Brightness; 
that  is,  on  the  Amount  of  Luminous  Vapor  in  the  Unit  of  Volume  of 
the  Source  of  Light. — We  have  now  to  consider  the  question: 
Is  the  optical  center  of  gravity  of  a  purified  homogeneous  light 
a  function  of  the  brightness  of  the  light  ?  Although  the  case 
of  sodium  light  is  somewhat  complicated,  we  shall  take  it  up 
first,  since  this  homogeneous  light  is  the  one  most  commonly 
used.  We  shall  assume  then,  in  what  follows,  completely 
purified  sodium  light ;  that  is,  light  consisting  of  the  two  D 


613 


A  in  p.  /u 


589,62     589,02 
Fig.  69. 

lines  and  extremely  little  of  neighboring  wave-lengths,  such 
as  is  obtained  by  the  method  of  spectral  purification  described 
in  the  last  paragraph.  The  relative  distribution  of  brightness 
in  the  spectrum  of  this  sodium  light  corresponds  approxi- 
mately to  Fig.  69  in  which,  as  abscissas,  the  wave-lengths  A. 
are  expressed  in  j^f^,  while  the  ordinates  represent  the  inten- 
sities for  the  corresponding  wave-lengths.1  The  light  of  the 
line  D2  is,  according  to  Dietrich,  about  1.6  times  as  bright  as 
that  of  Dr  After  satisfactory  spectral  purification  light  be- 

1  The  false  light  is,  of  course,  much  too  bright  in  the  representation. 


565 


408  SODIUM    LIGHT 

tween  the  wave-lengths  613  w  and  565  HV,  approximately, 
will  enter  the  polarization  apparatus  ;  as  this  spectrum  is  very 
long  for  the  dimensions  chosen  in  the  figure,  only  the  middle 
and  end  portions  are  represented.  The  optical  center  of  gravity 
of  purified  sodium  light  from  all  sources  is  the  same  as  long  as  the 
mea?i  wave-lengths  of  the  two  D  lines,  and  also  their  relations  as 
regards  brightness,  are  constant.1 

We  may  consider  first,  a  source  of  sodium  light  of  constant 
luminosity,  which,  after  purification,  reaches  the  illumination 
lens  of  the  instrument  with  a  perfectly  definite  optical  center 
of  gravity,  and  ask  now  if  this  center  is  altered  if  the  light  at 
any  part  of  its  path  is  uniformly  weakened.  This  could  be 
the  case,  only  if  the  wave-lengths  were  variable  with  the  in- 
tensity. Now,  Lippich2  has  shown  experimentally  the  con- 
stancy of  wave-length  with  different  values  of  the  intensity  to 
within  Vioooooooo  of  the  value  of  the  wave-length.  His  conclusions 
were  later  confirmed  by  Ebert,3  who  obtained  results  by  the 
method  of  high  interferences  which,  with  proper  homogeneous 
light,  showed  constancy  in  wave-lengths  to  within  V],  000.000  f°r 
values  of  the  intensity  varying  between  the  limits  of  i  and 
250.  Ebert  was  able  to  show  for  the  light  of  the  two  D  lines 
especially,  that  a  diminution  to  3  per  cent,  of  the  original 
brightness  did  not  change  the  mean  wave-lengths  Vsooooo0^  their 
value  ;  that  is,  not  by  o.ooi  m*.  We  have  then  this  important 
result,  that  with  unchanged  emission  from  the  source  of  light,  the 
optical  center  of  gravity  does  not  vary  with  the  intensity.  • 

Now  let  us  suppose  the  emission  from  the  source  of  sodium 
light  to  change  by  altering,  for  example,  the  brightness.  As  far 
back  as  1871,  Zollner4  showed  that  when  by  moving  the  salt 
globule  more  or  less  completely  into  the  Bunsen  flame,  differ- 
ent amounts  of  sodium  vapor  were  produced,  the  line  D.,  in- 
creased in  width  more  rapidly  than  D,  with  increasing  bright- 
ness, and  that  D}  widened  more  rapidly  toward  the  side  of 
greater  wave-lengths  than  toward  the  other,  while  no  such  dis- 


1  The  continuous  spectrum  of  thejfalse  light  in  the  sodium  li^l't  dots  not  i-Ji.-uin^ 
the  optical  center  of  gravity  of  the  two  D  lines,  because  the  brightness  of  the  whole- 
range  of  the  narrow  portion  of  the  spectrum  front  which  light  enters  the  apparatus 
may  be  taken  as  constant. 

-'  I.ippich  :  Wiener  Sit/.uiiKsber.,  II  72,  355  (1875). 

«  Kbert  :  Wied.  Ann.,  33,  337  (1887). 

«  /.ollncr  :  Pogg.  Ann.,  143,  88  (1871). 


BRIGHTNESS  OF  THE  LIGHT  409 

placement  of  the  center  of  D2  on  widening  was  to  be  observed. 
From  these  observations,  it  follows  that  a  change  in  the  opti- 
cal center  of  gravity  is  indeed  possible  with  a  change  in  bright- 
ness in  the  sodium  light.  On  what  does  the  widening  of  a 
spectrum  line  depend  ?  As  even  the  most  homogeneous  spec- 
trum line  is  formed  by  a  series  of  elementary  rays  whose  wave- 
lengths are  infinitely  close  together,  it  must  follow  that  the 
intensities  of  the  elementary  rays  are  a  continuous  function  of 
the  wave-lengths.  The  brightness  of  the  spectrum  lines  can- 
not, therefore,  change  suddenly  on  the  sides  but  must  grad- 
ually decrease  to  zero.  If  such  a  line  is  broadened,  it  is  the 
intensities  of  just  those  wave-lengths  on  the  edges  of  the  spec- 
tral lines  which  are  so  much  increased  that  they  become  per- 
ceptible to  the  eye.  We  must,  of  course,  distinguish  between 
this  broadening  and  the  displacement  of  the  mean  wave-length 
(the  optical  center  of  gravity)  of  the  spectrum  line  in  question  ; 
this  displacement  may  depend  on  a  broadening  of  the  line  as 
well  as  on  a  change  in  the  form  of  its  intensity  curve. 

The  observations  of  Zollner  were  fully  confirmed  by  work 
of  Ebert.1  As  the  latter,  in  these  investigations,  made  quan- 
titative measurements  by  the  method  of  high  interferences  of 
the  changes  in  mean  wave-lengths  of  several  lines  of  the  spec- 
trum, so  that  we  have  full  data  concerning  the  amount  of  pos- 
sible displacements,  this  work  of  Ebert 's  must  be  regarded 
as  of  great  importance  in  polarimetry  and  will,  therefore,  re- 
ceive here  closer  attention.  In  his  experiments,  Ebert  employed 
a  Terquem  burner,  and  modified  the  emission  of  light  by 
moving  the  salt  globule  to  a  greater  or  less  depth  in  the  flame. 
As  long  as  the  salt  just  touches  the  edge  of  the  flame,  the 
vaporization  rind  brightness  are  small,  but  these  increase  as 
the  globule  is  pushed  further  into  the  flame  until  a  point  is 
reached  near  the  inner  cooler  zone  where  the  vaporization 
again  decreases.  With  such  alterations  in  brightness,  Ebert 
found  displacements  of  the  mean  wave-length  of  sodium  light 
amounting  to  0.044  f.iu,  and  increasing  toward  the  less  refran- 
gible end  of  the  spectrum,  with  increase  in  brightness.  At 
the  came  time  Ebert  showed  for  sodium  light  as  well  as  jor  sev- 
eral other  spectral  lines,  that  primarily  neither  the  thickness  of 

i  Ebert  :  Wied.  Ann.,  34,  39  (1888). 


410  SODIUM    LIGHT 

the  luminous  layer  nor  the  temperature  of  the  source  of  light  or 
the  chemical  changes  taking  place  in  it  cause  any  changes  in  the 
wave-length,  but  that  the  mean  wave-length  depends  simply  and 
alone  on  the  density  of  the  vapor  ;  that  is,  on  the  amount  of  vapor 
of  the  luminous  substance  in  the  unit  of  volume,  and  varies  with 
alterations  in  the  density  of  this  vapor.  It  is  also  true  that  the 
amount  of  chauge  for  the  different  sodium  salts  under  the 
same  conditions  of  vaporization  is,  in  general,  not  the  same  ; 
but  the  variations  are  not  large.  If  now  a  change  in  bright- 
ness obtained  by  aid  of  a  Terquem  burner  and  salt  bead  pro- 
duces a  displacement  of  the  optical  center  of  gravity  of  sodium 
light  amounting  to  0.044  W,  one  may  not  be  mistaken  in  as- 
suming that  with  much  greater  changes  in  illumination  the 
displacement  of  the  center  will  probably  be  still  more  marked. 
This  view  has  recently  been  completely  verified  by  Schonrock,1 
and  by  aid  of  polarization  apparatus  which  for  such  investiga- 
tions is  doubtless  more  sensitive  than  Ebert's  method  of  high 
interferences. 

Schonrock  worked  with  a  Lippich  half-shadow  instrument, 
and  employed  as  source  of  light  the  Linnemann  oxygen  blast- 
lamp  described  in  £142,  in  which  sticks  of  fused  sodium  car- 
bonate were  vaporized  ;  the  sodium  light  obtained  was  purified 
perfectly  by  a  flint  glass  prism  with  a  ray  path  of  about  3 
meters.  It  could  then  be  shown  easily  that  the  optical  center 
of  gravity  varied  considerably  with  the  brightness  of  the  flame, 
since  the  amount  of  an  angle  of  rotation  must  vary  corre- 
spondingly. If  by  use  of  a  perfect  quartz-plate  or  a  cane-sugar  so- 
lution an  angle  of  rotation  of  about  100°  is  obtained,  this  is  found 
to  decrease  about  1  40  seconds  of  arc  when  the  stick  of  sodium  car- 
bonate is  moved  more  and  more  into  the  hottest  part  of  the  flame. 
The  zero  point  of  the  instrument  is  in  no  wise  changed  in  the  op- 
erations. Therefore,  according  to  the  formula  developed  in  §148, 

-  266 


the  optical  center  of  gravity  of  sodium  light  must  be  moved 
about  o.  1  1  A*/*  with  increasing  brightness,  that  is,  about  one- 
fifth  of  the  distance  between  the  two  D  lines  and  toward  the 

1  Schonrock  :  "DieThatigkeitder  Physikalisch-technischen  Reichsanstalt,"  Ztschr. 
fur  Instrum.  17  (1897). 


BRIGHTNESS   OF   THE   UGHT  411 

red  end  of  the  spectrum.  This  displacement  is  in  the  same 
direction  as  shown  by  Kbert,  but  in  consequence  of  the  much 
greater  variation  in  brightness  is  more  than  twice  as  large  as 
he  found.  Without  doubt  by  working  with  the  du  Bois  soda 
pencils  described  in  §146  still  greater  displacements  of  the 
optical  center  could  be  demonstrated.  At  the  same  time 
Schonrock  found  in  complete  agreement  with  the  results  of 
Lippich  and  Ebert,  by  aid  of  a  Nicol  prism  placed  in  front  of 
the  illumination  lens  of  the  instrument,  that  with  constant 
emission  from  the  source  of  light  the  wave-length  of  the  optical 
center  of  gravity  does  not  change  with  the  intensity  of  the 
light.  The  displacement  of  the  center  for  sodium  light  is 
doubtless  due  not  only  to  the  unsymmetrical  widening  of  the 
line  Dlf  but  also  to  a  change  in  the  relation  of  the  lines  Dl  and 
D2  to  each  other  as  regards  brightness.  But  this  point  remains 
to  be  cleared  up  by  future  work.  In  §148  the  optical  center 
of  gravity  of  perfectly  purified  sodium  light  is  calculated  as 
589.25  fiif*  ;  we  know  now  that  this  value  is  probably  correct 
for  a  certain  mean  brightness  of  the  sodium  light,  but  that  in 
addition  it  may  vary  by  o.  1 1  yu^u  by  changes  in  the  emission 
from  the  source  of  light. 

As  with  sodium  light  the  optical  centers  for  all  other  lines 
or  perfectly  purified  homogeneous  lights  change  more  or  less 
strongly  with  variations  in  the  amount  of  vapor  in  the  unit 
volume  of  the  source  of  light.  In  his  work  referred  to  above 
Ebert  made  quantitative  measurements  of  the  displacement 
for  some  lines  of  thallium,  lithium,  potassium,  and  strontium. 
Without  exception  he  found  that  the  widening  of  the  lines  was 
stronger  toward  the  end  of  less  refrangibility  than  toward  the 
other,  so  that  with  increasing  brightness  the  optical  centers  of 
gravity  moved  toward  the  red  end  of  the  spectrum.  The  dis- 
placements observed  by  him  are  given  in  the  following  short 
table,  for  which  it  must  be  remembered  that  the  changes  of 
brightness  were  produced  by  aid  of  a  salt  bead  and  Terquem 
burner  only. 


4I2 


SODIUM    LIGHT 


DISPLACEMENT  OF  THE  OPTICAL  CENTERS  OF  GRAVITY  OF  SOME  SPEC- 
TRUM LINES,  ACCORDING  TO  EBERT. 


Source  of  light. 

Wave-lengths  in  MM- 

Displacement  in  MM- 

T  iCI     T  i  CO 

670.8 

535-1 
768.0 
404.6 
460.8 

0.06 
0.026 
0.046 
.  .  -1 
0.019 

X1C1  

KC1 

KC1    

SrOl 

In  their  paper  "  Ueber  die  Spectren  der  Alkalien,"  Kayser 
and  Runge  make  the  following  statement  :2  "  The  majority  of 
the  lines  of  the  alkalies  are  not,  however,  sharply  denned, 
they  broaden  by  increase  in  the  amount  of  vapor,  and  either 
toward  both  sides  or,  more  commonly,  toward  the  red  end  of 
the  spectrum,  occasionally  however,  toward  the  violet  end  only. 
Such  broadened  lines  often  reach  a  width  of  two  to  three  yw/**." 
The  general  conclusion  is  therefore  warranted  that  the  optical 
center  of  gravity  of  a  spectrum  line  is  not  a  constant  but  is  a 
function  of  the  emission  from  the  source  of  light.  Since  the 
Arons  mercury  light,  to  be  described  later,  has  recently  been 
made  available  for  polarimetric  measurements,  it  may  be  in 
order  to  discuss  briefly  the  spectrum  lines  of  mercury.  It  is 
well  known  that  the  different  spectra  of  one  and  the  same  chem- 
ical element  show  variations  depending  on  whether  the}7  are 
flame,  spark,  or  arc  light  spectra.  In  the  case  of  mercury 
these  differences  are  very  large,3  so  that  the  strongest  lines  in 
one  spectrum  may  be  in  part  wholly  wanting  in  the  other.  It 
would  appear  probable,  therefore,  that  the  lines  of  mercury 
must  change  strongly  with  changes  in  the  light  arc,  which  in 
turn  changes  with  the  intensity  of  the  producing  current  ; 
Ebert  states  that  the  bright  green  mercury  line,  546  /*/*,  in- 
creases on  one  side  only,  which,  in  all  probability,  would  have 
a  displacement  of  its  optical  center  of  gravity  as  a  consequence. 
What  conclusion  must  be  drawn  now  for  polarimetry  from  this 
variability  of  the  optical  center  of  gravity  of  purified  homo- 
geneous light  ? 

1  A  displacement  was  found  but  not  measured. 
*  Kayser  and  Runge  :  Wied.  Ann.,  41,  302  (1890). 
»  Kayser  and  Runge :  Ibid.,  43,  385  (1891). 


ROTATION  OF  SODIUM    LIGHT    BY    QUARTZ  413 

In  the  first  place  in  all  polarimetric  measurements,  whether  of 
absolute  amounts  of  rotation,  or  of  differences  of  rotations,  the 
emission  from  the  source  of  light  must  be  kept  constant,  and  this 
may  be  reached  in  a  satisfactory  manner  even  in  investigations 
of  length.  In  the  second  place  it  is  necessary  that  along  u'ilh  the 
rotations  the  optical  center  of  gravity  of  the  light  used  must  be 
determined  and  defined  with  corresponding  accuracy,  as  otherwise 
the  measurements  of  different  observers  are  not  comparable  with 
each  other.  It  is  not  sufficient  to  merely  state  that  one  has 
used  sodium  light  after  perfect  spectral  purification,  as  even 
then  its  optical  center  of  gravity  remains  uncertain  to  about 
o.  i  pi*.  This  uncertainty  corresponds  to  a  difference  in  rota- 
tion of  25"  in  an  angle  amounting  to  20°;  such  an  angle  may 
often  be  measured  without  difficulty  to  within  8".  If  then  the 
expected  accuracy  of  the  method  is  not  to  be  illusory  the  wave- 
length of  the  corresponding  optical  center  of  gravity  must  be 
given  to  within  0.03  /^.  From  this  it  is  seen  that  in  general 
an  angle  of  rotation  may  be  found  with  a  good  polariscope  with 
a  degree  of  accuracy  which  is  much  greater  than  the  accuracy 
with  which  the  corresponding  optical  centers  of  gravity  may  be 
measured  and  expressed.  Whether  it  will  ever  be  possible  to 
carry  the  determination  of  the  optical  centers  of  homogeneous 
lights  so  far  that  they  will  correspond  in  accuracy  to  the 
delicacy  of  the  modern  polarimetric  apparatus,  remains  for  the 
future  to  show.1 

151.  Absolute  Determination  of  the  Rotation  of  Sodium  Light  for 
Quartz — As  we  have  now  seen  the  several  variations  to  which 
the  optical  center  of  gravity  of  sodium  light  from  different 
sources  is  subject,  we  shall  next  attempt  a  review  of  the  work 
done  on  the  absolute  rotation  of  quartz  for  sodium  light,  as 
already  explained  in  §44,  taking  these  disturbing  variations 
into  consideration.  Passing  over  the  oldest  and  very  inaccurate 
measurements  we  come  at  once  to  the  work  of  v.  Lang.  A 
value  is  often  quoted  from  work  of  v.  Lang  done  in  1875* 

1  This  will  be  possible  as  soon  as  the  rotation  dispersion  of  quartz  is  sufficiently 
well  established.  Such  an  accurate  determination  of  the  rotation  dispersion  of  quartz 
may  be  made,  as  is  sufficiently  clear  from  what  has  been  said,  only  by  aid  of  the  Fraun- 
hofer  lines,  and  after  improvements  in  methods  discussed  in  the  chapter  on  "Determi- 
nation of  Rotation  Dispersion." 

-'  v.  I^ang :  Wiener  Sitzungsber.,  II,  71,  707  (1875). 


414  SODIUM    LIGHT 

which  is  misleading  ;  in  this  work  v.  Lang  investigated  the 
dependence  of  the  circular  polarization  of  quartz  on  the  tem- 
perature, but  did  not  determine,  as  he  himself  explains,  the 
absolute  value  of  the  angle  of  rotation,  assuming  the  rotating 
power  per  millimeter  as  known.  But  in  a  second  investiga- 
tion he  made  an  absolute  determination.1  By  the  aid  of  the 
Broch  method  to  be  described  later,  with  sunlight,  and  using 
a  double  prism  of  right  and  left  quartz  about  33  mm.  thick, 
he  found  at  20°  C.  a  rotation  of  21.724°  per  millimeter  for  the 
line  D.  We  must  take  then  as  the  optical  center  of  gravity 
the  mean  between  the  two  D  lines,  that  is,  589.3  yw/^. 

In  1878  Jouberf'  made  absolute  rotation  determinations  ;  but 
as  he  worked  with  the  Laurent  instrument  and  sodium  light, 
the  optical  center  of  gravity  being  quite  indefinite,  his  results 
do  not  call  for  consideration. 

Following  the  Broch  method  with  sunlight,  Soret  and 
Sarasin3  determined  the  rotation  of  two  quartz  plates,  about  30 
and  60  mm.  in  thickness,  for  each  of  the  two  D  lines.  For  the 
middle  of  the  two  lines  (589.3  //^)  we  find  as  the  mean  value 
from  these  figures  21.708°  per  millimeter,  for  20°  C. 

Soret  and  Guye4  have  made  determinations  with  the  same 
plate  about  60  mm.  thick,  used  by  Soret  and  Sarasin.  As  they 
worked  with  a  Cornu  instrument  (§110)  and  sodium  bromide 
light,  purified  through  the  spectrum,  the  wave-length  of  the 
optical  center  may  be  taken  as  before,  as  589.3  WJL.  The  value 
of  21.723°  per  millimeter  at  20°  C.  may  be  calculated  as  the 
mean  value  from  their  experiments. 

More  recently  absolute  rotation  determinations  have  been 
made  by  Gumlich.5  The  optical  center  may  be  again  taken 
as  589.3  w*,  as  he  worked  with  the  Lippich  instrument  and 
spectrum  sodium  light.  He  found,  with  four  quartz  plates  of 
approximately  5,  6,  8,  and  10  mm.  thickness,  values  which 
varied  between  21.717°  and  21.731°  per  millimeter  at  20°  C. 
The  mean  value  was  21.724°. 

Finally,  the  author  is  in  a  position  to  give  his  own  results  for 

1  T.  Lang:  Wiener  Sitzungsber.,  II,  74,  209  (1876). 

4  Joubert :  Compt.  rend.,  87,  497  (1878). 

8  Soret  and  Sarasin  :  Ibid.,  95,  635  (1882). 

4  Soret  and  Guye  :  Ibid.,  115,  1295  (1892). 

6  Gumlich  :  Ztschr.  fur  Instrum.,  16,  97  (1896). 


RELATION   OF   THE    ANGLES   OF   ROTATION  415 

the  absolute  rotation  of  quartz.  He  (Schb'nrock)  made  his 
determinations  with  a  perfect  quartz  plate,  about  5  mm.  thick, 
by  aid  of  a  Lippich  instrument  and  sodium  light  which  was 
absolutely  purified  through  the  spectrum,  so  that  the  optical 
center  may  be  taken  as  589.3  /*/*.  From  many  measurements 
made  at  different  times  the  value  21.722°  per  millimeter  at  20° 
C.,  and  accurate  to  ±0.003°,  i§  calculated,  corresponding  to 
the  true  optical  center  of  gravity  of  the  sodium  light  used  ; 
but  this  latter  has  not  yet  been  found  with  a  satisfactory  degree 
of  accuracy. 

As,  therefore,  all  these  observers  have  made  their  determina- 
tions very  nearly  for  the  same  center,  589.3  nn,  their  measure- 
ments must  be  comparable  with  each  other.  The  results  are 
given  in  the  following  short  table  : 


Observer. 


Rotation  of  quartz  per 
millimeter  at  20°  C. 


v.  Lang 2i.724; 

Soret  and  Sarasin 21.708 

Soret  and  Guye 21.723 

Gumlich 21.724 

Schonrock 21.722 


With  exception  of  the  value  of  Soret  and  Sarasin  the  agree- 
ment is  quite  a  remarkable  one.  It  may  be  said  with  certainty 
that,  using  perfectly  pure  sprectrum  sodium  light,  i  mm.  of 
quartz,  with  a  certain  mean  brightness  of  the  light,  will  rotate 
the  plane  of  polarization  exactly  21.723°  at  a  temperature  of 20° 
C.  But  on  account  of  the  variation  in  the  optical  center  of 
gravity  with  the  brightness  of  the  source  of  light  the  rotation 
may  vary  by  about  ±0.004°  Per  millimeter.  There  may  accord- 
ingly be  some  reason  for  a  re  determination  of  the  absolute  rotation 
of  quartz  only  when  the  corresponding  optical  center  is  found  with 
an  equal  degree  of  accuracy. 

152.  Relation  of  the  Angles  of  Rotation,  ctj  and  aD.  — In  addition 
to  the  illumination  of  saccharimeters  a  white  light  is  employed 
in  the  determination  of  the  angle  of  rotation,  or,-,  for  mean  yel- 
low rays  by  aid  of  the  Robiquet  polariscope  (§100).  As  seen 
by  the  expression  itself,  ' '  mean  yellow  rays,"  the  angle  of  rota- 


4l6  SODIUM    LIGHT 

tion,  ah  is  not  accurately  defined;  the  wave-length  correspond- 
ing to  it  may  be  taken  as  about  556  /'A'.1  The  rotation  referred 
to  this,  following  Biot's  suggestion,  is  represented  by  oij  (jaune 
moyen). 

As  the  wave-length  of  mean  yellow  light  is  less  than  that  of 
D  (589  ///*)  the  values  for  otj  are  always  much  larger  than  those 
for  aD.  For  quartz,  as  an  illustration,  we  have  per  millimeter, 
aD  =  21.72°  and  otj  =  24.5°;  these  formulas  for  conversion  are 
therefore  used : 

(*,=         —  <*D  =  i .  1 2&aD,  and  UD  =  -  -  ' '     a  =  o.  887  a-. 
21.72  24.5 

But  on  account  of  unequal  rotation  dispersion  for  different  sub- 
stances the  relation  ofaD  to  a,  is  a  variable  one.  The  deviations 
from  the  above  values  may  amount  to  10  per  cent,  or  more. 

As  the  rotation  a}  does  not  correspond  to  any  accurately 
definable  ray,  the  determination  of  or,-  is  not  satisfactory  and  at 
the  present  time  is  scarcely  made.  It  must  be  pointed  out 
here  that  when  a  rotation  is  measured  in  a  half-shadow  appa- 
ratus with  white  light  the  angle  obtained  is  not  accurately  atj ; 
see  §153. 

There  are  in  the  literature  a  large  number  of  observations 
made  by  Biota  with  red  light  obtained  by  aid  of  glass  colored 
with  cuprous  oxide,  and  corresponding  approximately  in  refran- 
gibility  to  the  Fraunhofer  line  C  (656  /*/<. )  From  the  state- 
ment that  this  light  is  rotated  18.41°  by  i  mm.  of  quartz  its 
wave-length  is  calculated  as  about  637  nf*.  For  quartz,  there- 
fore, the  rotation  of  this  red  light  is  related  to  that  for  D  as  i 
to  1.18. 

153-  Optical  Center  of  Gravity  of  White  Light.  —  The  chemist  is 
sometimes  in  the  position  where,  instead  of  using  yellow  light, 
he  is  obliged  to  employ  white  light.  We  shall  therefore  con- 
sider the  optical  center  of  gravity  of  white  light  more  closely, 
under  the  assumption  that  the  rotations  are  measured  with  a  Lip- 
pick  half -shadow  instrument.  An  optical  center  of  white  light 
can  not  be  directly  defined,  as  it  is  subject  to  considerable  va- 
riations according  to  the  source  of  light  employed.  Sunlight, 
gas  light,  petroleum  light,  Welsbach  light,  electric  light,  zir- 

1  L,andolt :  Sitzungsber.  der.  Akad.  Berlin,  1896,  p.  790. 

2  Biot :  M£m.  de  1'  Acad.,  3,  177  (1820). 


OPTICAL   CENTER   OF   GRAVITY  417 

cona  light,  lime  light,  and  so  on,  have  all  a  different  distribution 
of  brightness  in  the  spectrum  and,  therefore,  according  to 
§147,  different  optical  centers  of  gravity.  With  white  light 
illumination,  however,  only  very  small  angles ,  at  most  j° ,  may 
be  measured,  because  with  larger  rotations,  the  field  of  view  shows 
considerable  color  variations.  And,  above  all,  the  investigated 
substances  must  be  colorless  and  as  clear  as  water.  If  the  active 
substance  is  colored,  it  will  have  an  absorption  spectrum,  and 
will,  therefore,  alter  more  or  less  strongly  the  composition  of 
the  white  light;  the  white  light  will,  at  the  same  time,  be 
filtered  by  the  colored  body,  and  in  this  way  the  relative 
brightness  of  different  parts  of  the  spectrum  of  the  original 
light  will  be  totally  altered.  For  one  and  the  same  source  of 
white  light  the  optical  center  varies,  therefore,  from  substance 
to  substance,  if  they  are  colored.1  That  these  changes  in  the 
optical  center  are  very  considerable  is  shown  by  the  obser- 
vations of  Holzer,-  the  results  of  which  could  be  predicted  from 
what  has  been  said.  In  the  investigation  of  colored  sub- 
stances, therefore,  even  when  the  color  is  slight,  the  use  of 
white  light  must  be  given  up  and  an  intense  sodium  light  pro- 
vided. 

The  following  experiments  were  made  to  find  the  optical 
center  of  one  white  light,  the  Welsbach  light,  with  some 
degree  of  accuracy.  The  small  angles  of  rotation  were  secured 
by  combination  of  positive  and  negative  quartz-plates  ;  a  posi- 
tive plate  about  1.49  mm.  thick  and  a  negative  plate  about 
1.46  mm.  thick,  gave  together  a  rotation  of  about  -f-  0.6°,  while 
the  same  negative  plate  with  a  positive  plate  about  1.6  mm. 
thick  gave  a  positive  rotation  of  about  2.9°.  These  two  angles 
of  rotation  were  measured  in  the  Landolt  apparatus  (§117) 
with  the  following  three  sources  of  illumination  :  First,  with 
sodium  light  made  by  the  Landolt  sodium  lamp  and  purified 
by  the  Lippich  sodium  light  filter,  then  with  the  Welsbach 
light  filtered  through  a  layer  of  6  per  cent,  potassium  dichro- 
mate  solution  1.5  cm.  thick,  and  finally  with  pure  Welsbach 
light.  In  using  the  last  sources  of  light,  the  field  of  view 
was  colored,  especially  in  measuring  the  larger  angle  of  rotation  ; 

1  The  I^andolt  ray  filters  depend  on  this. 
-  Holzer:  Ber.  d.  chera.  Ges.,  15,  1932  (1882). 
27 


418 


WHITE    LIGHT 


notwithstanding  this,  the  adjustment  was  always  made  to 
secure  uniform  shade  as  nearly  as  possible,  the  error  of  adjust- 
ment being  in  the  mean  about  ±1.5  minutes  of  arc,  with  a 
half-shadow  of  3°.  An)'  effects  of  temperature  changes  may 
be  eliminated  in  such  long  experiments  by  regularly  changing 
the  sources  of  light  and  employing  them,  for  example,  in  this 
order,  I,  II,  III,  I,  III,  II,  I,  so  that  the  mean  values  for  each 
source  of  light  correspond  to  one  and  the  same  mean  tempera- 
ture. The  results  obtained  are  given  in  the  following  table  :! 


By  quartz-plates. 

• 

Sodium    light 
purified  by  the 
Lippich    filter. 

Welsbach  light 
through  layer  of 
6  per  cent,  solu- 
tion   of    KoCroO7 
1.5  cm.  thick.  " 

Simple  Wels- 
bach light. 

0.60° 
2-95° 
589.3 

0.61° 

2-94° 
539 

0.68° 
3-39° 
55i 

Optical  center  in  /*/*  

To  within  about  ±  0.01°,  the  same  angles  are  found  with 
the  pure  sodium  light  and  the  filtered  Welsbach  light,  so  that 
the  optical  center  of  the  latter  may  be  taken  also  at  589  /U./M. 
On  the  other  hand,  the  results  found  with  the  simple  Wels- 
bach light,  an,,  are  much  larger  than  the  corresponding  aD.  If 
we  recall  now  that  the  rotation  of  quartz  for  pure  sodium  light 
is  21.72°,  we  may  calculate  by  aid  of  the  known  dispersion 
formulas  for  quartz  that  the  optical  center  of  gravity  of  the 
Welsbach  light  is  about  55 1  /A/A.  We  have  then  the  conver- 
sion formulas  : 

aw=  1.1490^,  and  an  =  0.8700^. 

But  as  the  relation  of  t*D  to  atw  varies  in  different  substances 
because  of  unequal  rotation  dispersions,  it  must  always  be  re- 
membered that  for  other  bodies  than  quartz,  the  values  of  ctn 
calculated  by  the  above  factor  from  observations  of  au  may  be 
in  error  to  the  extent  of  10  per  cent  or  more.  It  is,  therefore, 
recommended  not  to  use  the  simple  Welsbach  light  at  all,  but 
when  necessary,  to  employ  this  light  purified  by  the  potassium 
dichromate  solution  as  above  defined,  since  in  this  case  a  re- 
duction is  not  required. 

If  one  is  obliged  to  measure  angles  of  more  than  3°  with 

1   Without  doubt,  other  results  would  be  obtained  by  a  color-blind  eye. 


DETERMINATION   OF    ROTATION   DISPERSION  419 

white  light,  this  should  not  be  done  under  any  circumstances 
with  a  half-shadow  instrument  with  circular  graduation,  but 
the  rotation  may  be  found  with  a  half-shadow  saccharimeter ', 
with  which,  using  the  double  wedge-compensation,  angles  of 
±  34°  may  be  measured.  The  conditions  here  are  very  much 
more  favorable,  because  the  rotation  dispersion  is  very  largely 
compensated  by  the  action  of  the  compensating  quartz-plate  in 
the  wedge,  so  that  its  influence  on  the  measured  angle  of  rota- 
tion is  small  ;  colored  substances  also,  may  therefore  be  in- 
vestigated in  saccharimeters.  If  then  the  rotation  in  Ventzke 
degrees  be  multiplied  by  the  factor  0.347,  as  given  in  §127,  it 
may  be  at  least  said  that  the  product  obtained  gives  the  angle 
of  rotation  in  circular  degrees  for  sodium  light  with  an  error 
of  2  to  3  per  cent,  at  most.1  But  there  is  no  object  in  trying 
to  find  a  more  accurate  reduction  factor  for  each  individual 
substance,  because,  on  account  of  rotation  dispersion,  temper- 
ature effects,  and  variations  in  rotation  with  the  kind  of  illu- 
mination and  color  sense  of  the  observer,  it  is  never  possible  to 
make  accurate  determinations,  free  from  appreciable  systematic 
errors,  in  a  saccharimeter.  Whenever  possible,  therefore,  avoid 
the  use  of  a  saccharimeter  and  secure  for  illumination  of  a 
polariscope  the  most  intense  sodium  light  available,  the  pro- 
duction of  which  may  be,  moreover,  accomplished  without 
great  difficulty. 

d.  Determination  of  Rotation  Dispersion 

154.  Method  of  Broch. — To  find  the  rotation  dispersion  of  a 
substance,  it  is  necessary  to  determine  the  angles  of  rotation 
for  light  of  different  wave-lengths.  This  may  be  done  by  aid 
of  one  of  the  polarization  instruments  described,  using  differ- 
ent kinds  of  homogeneous  light,  which  method  will  be  later 
explained.  But  first,  several  other  methods  must  be  con- 
sidered. A  procedure  which  permits  the  determination  for  a 
whole  series  of  rays  of  known  wave-lengths  was  given  by 
Broch,2  and  simultaneously  by  Fizeau  and  Foucault.3  In  this 
process,  illumination  is  furnished  by  sunlight  which,  by  aid  of 

1  This  follows  from  the  data  of  L,andolt  :  Sitzungsber.  der  Akad.,   Berlin,  p.  959 
(1887). 

2  Broch  :  Dove's  Repert.  d.  Phys.,  7,  113  (1846). 

3  Fizeau  and  Foucault  :  Compt.  rend.,  21,  1155  (1845). 


420  DETERMINATION   OF   ROTATION   DISPERSION 

a  heliostat,  is  thrown  horizontally  into  a  darkened  room.  The 
rays  pass  in  the  following  order  :  the  vertical  slit  A  (Fig.  70), 
the  polarizer  B,  the  analyzer  C,  the  prism  D  placed  in  position 
of  minimum  deviation,  and  the  telescope  E  F  which  must  be 


F 

Fig.  70. 

provided  with  cross  hairs.  In  order  to  adjust  the  apparatus, 
the  principal  section  of  the  movable  analyzer  C  is  placed  paral- 
lel to  the  principal  section  of  the  polarizer  B,  the  slit  A  is  illu- 
minated \vith  sodium  light  and  the  ocular  F  of  the  telescope  is 
focused  sharply  on  the  image  of  the  slit  A  formed  by  the 
achromatic  objective  E.  On  removing  the  sodium  light  and 
admitting  sunlight,  a  pure  spectrum  with  the  Fraunhofer  lines 
is  seen  with  the  ocular  F.  In  order  to  bring  any  desired  part 
of  the  spectrum  into  the  center  of  the  field  of  view,  the  tele- 
scope must  be  movable  horizontally  around  a  fixed  axis  pass- 
ing through  the  center  of  the  prism.  First,  the  anal)7zer  C  is 
placed  in  the  position  of  greatest  darkness,  without  an  active 
substance  following  ;  this  is  the  zero  point.  Then  when  the 
active  body  is  placed  between  C  and  B,  the  spectrum  with 
the  Fraunhofer  lines  appears  again  in  the  telescope.  If  now 
the  analyzer  C  is  turned,  a  position  is  found  at  which  a  ver- 
tical dark  band  appears  in  the  field  of  view  and,  with  further 
rotation  of  C,  moves  across  it  ;  an  essential  condition  for  this, 
however,  is  that  the  rotation  dispersion  of  the  substance  must 
be  rather  large  as  compared  with  the  dispersion  of  the  prism. 
The  phenomenon  of  the  dark  bands  depends  on  the  fact,  that 
in  the  rotation  of  the  analyzer  those  rays  are  extinguished, 
one  after  the  other,  whose  planes  of  polarization  coincide  with 
the  principal  section  of  the  analyzer.  If  the  cross  hairs  of  the 
telescope  are  focused  on  one  of  the  Fraunhofer  lines  at  the 
start,  and  then,  by  movement  of  the  analyzer,  the  dark  band 
is  brought  to  center  with  the  cross  hairs,  the  rotation  read  off 
on  the  circle  shows  the  amount  of  rotation  for  the  line  in 


METHOD   OF    BROCH 


42I 


question.  In  this  manner  the  rotation  for  each  one  of  the 
Fraunhofer  lines  may  be  found.  In  place  of  cross  hairs,  it  is 
preferable  to  employ  parallel  fibers.  The  dark  band  is 
narrower  and  sharper,  the  larger  the  angle  of  rotation,  and 
consequently,  the  rotation  dispersion.  The  Fraunhofer  lines 
and  the  corresponding  wave-lengths  are  given  in  the  table 
below  : 


Fraunhofer  lines. 

Wave-lengths 
in  iJ.fi. 

Fraunhofer  lines. 

Wave-lengths 
in  /U./K. 

A 

759-4 

b 

517.5 

a 

718.6 

P 

486.1 

B 

686.7 

G 

430.8 

C 

656.3 

h 

410.2 

D 

589.3 

H 

396.9 

E 

527.0 

Soret  and  Sarasin1  in  their  determination  of  the  rotation  dis- 
persion of  quartz  have  avoided  the  rather  inaccurate  zero-point 
adjustment  in  this  manner  that  they  placed  a  negative  quartz- 
plate,  for  example,  in  position  first  and  brought  the  dark  band 
into  coincidence  with  a  line  of  the  spectrum  ;  then,  after  re- 
moving this  plate,  a  positive  one  wras  substituted  and  by  move- 
ment of  the  analyzer  the  dark  band  was  again  brought  into 
coincidence  with  the  same  line  of  the  spectrum.  From  the 
rotation  of  the  analyzer  there  is  found,  therefore,  for  the  line 
in  question,  an  angle  which  corresponds  to  that  of  a  positive 
or  negative  quartz-plate,  the  thickness  of  which  is  equal  to  the 
combined  thicknesses  of  the  positive  and  negative  plates  used. 

Through  several  improvements,  Lippich1  has  made  the  Broch 
method  a  tolerably  accurate  one,  but  for  the  details,  his 
original  paper  must  be  consulted. 

Finally,  by  use  of  a  quartz  double  plate  of  variable  thick- 
ness, G.  Wiedemann3  has  essentially  improved  the  Broch 
method.  The  double  plate  consists  of  two  quartz  wedges 
whose  principal  surfaces  are  ground  vertically  to  the  optical 
axis,  and  each  one  of  which  consists  of  an  upper  right-rotating 

1  Soret  and  Sarasin  :  Compt.  rend.,  95,  635  (1882).  Their  method  has  been  given 
above  by  the  author  in  more  practical  form. 

-  I,ippich  :  Wiener  Sitzungsber.  II,  85,  307  (1882). 

3  G.  Wiedemann  :  L,ehre  von  der  Elektricitat,  3,  914  (1883). 


422  DETERMINATION   OF   ROTATION   DISPERSION 

and  a  lower  left-rotating  half.  By  aid  of  a  micrometer  screw 
one  of  these  wedges  may  be  moved  in  front  of  the  other.  The 
vertical  slit  A  (Fig.  70)  is  brought  between  B  and  C,  and  at 
a  slight  distance  from  B,  and  then  between  A  and  B,  and 
immediately  behind  the  slit,  the  double  plate  is  so  placed  that 
its  junction  edges  lie  horizontally.  The  double  plate  must 
stand  vertically  to  the  direction  of  the  light  rays,  so  that  they 
will  pass  through  in  the  direction  of  the  axis.  Using  sunlight, 
the  spectrum  with  the  Fraunhofer  lines  is  found  as  before  in 
the  telescope,  these  lines  being  broken  into  upper  and  lower 
halves  by  the  horizontal  juncture  surface  of  the  double  plate. 
As  the  plane  of  polarization  of  each  color  is  turned  to  the  right 
by  the  upper  plate,  and  through  the  same  angle  to  the  left  by 
the  lower  plate,  it  follows  that  for  any  position  of  the  analyzer 
the  spectrum  does  not  show  the  same  colors  above  and  below, 
but  at  any  given  time  those  are  extinguished  for  which,  above 
and  below,  the  angles  of  rotation  differ  by  some  multiple  of 
1 80°.  If  then,  the  same  color  is  to  be  extinguished  above 
and  below,  the  rotation  for  this  color  must  be  a  multiple  of 
90°  ;  in  this  case,  the  polarizer  and  analyzer  must  stand  in 
crossed  or  parallel  position.  Just  which  color  is  extinguished 
depends  on  the  thickness  of  the  quartz  double  plate  ;  if  this 
thickness  may  be  varied  within  sufficiently  wide  limits,  it  will 
be  possible  to  follow  the  bands  shut  out  from  one  end  of  the 
spectrum  to  the  other  and  to  bring  them  to  coincide  with  any 
Fraunhofer  lines  desired.  The  determination  of  an  angle  of 
rotation  for  a  Fraunhofer  line  is  then  made  as  follows  :  The 
line  in  question  is  brought  between  the  parallel  threads,  the 
analyzer  is  then  turned  until  at  some  point  of  the  spectrum 
the  two  dark  bands  stand  with  one  exactly  above  the  other, 
and  the  movable  wedge  is  then  shoved  until  the  dark  band 
lies  between  the  parallel  threads  ;  this  gives  the  zero-point 
position  of  the  analyzer.  If  the  active  substance  is  now  placed 
between  the  analyzer  and  the  slit,  the  bands  no  longer  stand 
one  above  the  other,  but  to  secure  this  the  analyzer  must  be 
turned  through  the  same  angle  by  which  the  line  chosen  is 
rotated  by  the  active  body.  It  is  assumed  that  the  tempera- 
ture of  the  double  plate  does  not  appreciably  change  during 
the  measurements.  The  spectropolarimeter  constructed  much 


THE    METHOD   OF   V.  LANG  423 

later  by  v.  Fleischl1  is  nothing  but  a  bad  copy  of  the  Wiede- 
mann  apparatus,  the  variable  double  plate  of  which  is  replaced 
by  a  simple  quartz  double  plate  of  constant  thickness,  with 
which  the  rotation  for  a  single  definite  color  only  may  be 
measured. 

155.  The  Method  of  v.  Lang. — The  main  drawback  in  the 
Broch  method  is  that  it  depends  on  the  not  always  available 
sunlight.  But  v.  Lang  has  shown'2  that  the  Broch  procedure 
may  be  easily  so  changed  that  instead  of  sunlight  with  the 
Fraunhofer  line?  ordinary  white  light  with  artificial  spectral 
lines  may  be  employed.  The  arrangement  of  the  apparatus  is 
preferably  that  shown  in  the  illustration  (Fig.  71).  By  aid  of 
the  lens  B,  a  sharp  image  of  the  source  of  white  light  A  is  thrown 
on  the  slit  C.  The  light  passing  the  slit  is  led  first  through 
a  simple  Mitscherlich  polariscope  consisting  of  the  illumination 
lens  D,  the  polarizer  E,  and  the  analyzer  F,  which  may  be 
rotated,  and  then  through  an  ordinary  spectroscope  G  to  L.  The 


I 

B    D 


no 


L 

Fig:  71. 

focal  distance  of  the  illumination  lens  D  is  equal  to  half  the 
distance  between  D  and  G,  and  the  slit  C  is  so  placed  that  a 
sharp  image  of  it  may  be  formed  by  D  at  the  objective  slit  G 
of  the  spectroscope.  G  is  situated  in  the  focus  of  the  achro- 
matic lens  H,  and  the  prism  J  in  the  position  of  minimum 
deviation.  The  spectrum  produced  in  the  achromatic  telescope 
K  is  seen  at  the  ocular  L  along  with  two  parallel  vertical  lines 
or  fibers.  The  telescope  K  L  is  movable  horizontally.  The 
adjustment  of  the  spectroscope  is  accomplished  in  the  usual 
well  known  manner.  The  following  operations  are  necessary 
to  determine  the  angle  of  rotation  of  a  substance  for  a  given 
spectrum  line  :  i .  The  zero  point  is  found  by  turning  the 
analyzer  F  to  the  position  of  greatest  darkness.  2.  The  white 

i  v.  Fleischl  :  Repert.  d.  Exper.-Phys.,  21,  323  (1885);  Wied.  Ann.  Beibl.,   9,  634 
0835). 

-  v.I^ang:  Pogg.  Ann.,  156,  422  (1875). 


424  DETERMINATION    OF    ROTATION    DISPERSION 

light  is  shut  off  and  between  B  and  C,  and  near  the  slit  the 
apparatus  is  placed  which  furnishes  the  lines  of  the  homo- 
geneous light  in  question,  and  the  analyzer  F  is  so  turned  as  to 
transmit  the  largest  possible  amount  of  light.  A  continuous 
spectrum  is  no  longer  seen  in  the  telescope,  but  only  the  sharp 
and  bright  spectrum  lines.  The  telescope  is  then  turned 
horizontally  until  the  desired  bright  line  comes  between  the 
parallel  hairs.  The  source  of  homogeneous  light  is  then  re- 
moved, the  strong  white  light  A  admitted,  the  active  substance 
placed  in  position  and  the  analyzer  F  turned  until  a  black  band 
appears  in  the  telescope.  By  further  turning  the  analyzer, 
this  band  is  brought  exactly  between  the  parallel  hairs,  and 
the  analyzer  graduation  is  then  read  off.  By  again  admitting 
the  line  of  the  homogeneous  light  it  may  be  determined 
whether  or  not  the  position  of  the  telescope  has  suffered  any 
change.  If  it  is  desired  to  work  with  the  Wiedemann  double 
quartz  plate  of  variable  thickness,  described  in  the  preceding 
paragraph,  F  must  be  placed  between  Gand  H,  and  the  double 
plate  directly  in  front  of  G  and  turned  toward  the  polarizer  E. 
In  regard  to  making  the  determinations  of  rotation  the  direc- 
tions of  the  last  paragraph  obtain. 

In  the  production  of  the  spectrum  lines  various  sources  of 
homogeneous  light  may  be  used.  Salts  of  metals  may  be  in- 
troduced into  the  Bunsen  flame  by  a  platinum  loop,  and  in 
particular  the  chlorides  or  carbonates  of  sodium,  lithium,  thal- 
lium, potassium,  and  strontium.  The  light  of  a  Geissler  hy- 
drogen tube  may  be  employed  also.  If  a  little  mercury  or 
some  bits  of  cadmium  are  introduced  into  a  Geissler  tube,  the 
light  emitted  on  warming  these  metals  may  be  used.  In  the 
following  table  all  these  artificial  lines  are  given  with  their 
wave-lengths,  and  as  seen,  they  are  sufficient  for  the  deter- 
mination of  the  rotation  dispersion  of  a  substance. 


LIPPICH' S   METHOD 


425 


Color  of  the  lines. 

Source  of  light. 

Wave-lengths  in  M/UL. 

Ka 

768.0 

Red 

Li  a 

670.8 

Ha 

656.3 

Cd 

643.8 

Na 

589.3 

Yellow 

Hg 

579-0 

Hg 

576.9 

Hg 

546.1 

Green 

Tl 
Cd  4 

535-1 
508.6 

H0 

486.1 

Cd5 

480.0 

Blue 

Cd  6 

467.8 

Sr  8 

460.8 

Hg 

435-9 

H7 

434-0 

Violet 

Hg 

K 

407.8 
404.6 

156.  Lippich's  Method. — The  methods  of  Broch  and  v.  Lang 
give  more  accurate  results  the  larger  the  rotation  dispersion. 
But  if  this  is  small  the  dark  band  is  broad  and  not  sharp  on 
the  edges  so  that  the  adjustment  is  very  inaccurate.  In  this 
case  it  is  better  to  employ  the  method  of  Lippich1  in  the  meas- 
urement of  rotation  dispersion.  In  this  method  the  light  passes 
into  the  spectroscope  first  and  then  into  the  polarization  ap- 
paratus, which  should  be,  preferably,  the  sensitive  Lippich 
half-shadow  instrument  with  double  or  triple  field.  The  ar- 
rangement of  the  parts  is  shown  in  Fig.  72.  By  aid  of  the 
lens  B  a  sharp  image  of  the  bright  white  light  A  is  thrown  on 
the  vertical  slit  C  of  the  spectrometer.  C  is  situated  at  the 
focus  of  the  achromatic  lens  D.  The  prism  E  is  placed  in  the 
position  of  minimum  deviation,  and  the  light  rays  passing 
through  it  are  thrown  as  a  bright  spectrum  on  the  slit  screen 
G,  by  means  of  the  achromatic  lens  F,  and  in  such  a  manner 

:  Wiener  Sitzungsber.,  II,  91,  1070  (1885). 


426  DETERMINATION   OF   ROTATION   DISPERSION 

that  only  one  color  of  the  spectrum  may  pass  through  the  slit 
and  serve  for  the  illumination  of  the  polarization  apparatus. 
The  slit  G,  therefore,  represents  the  source  of  homogeneous 
light,  and  must  be  given  such  a  position  that  a  sharp  image  of 
the  slit  may  be  formed  by  the  illumination  lens  J,  of  the  polari- 


Fig.  72. 

zation  instrument,  on  the  analyzer  diaphragm.  In  order  to 
center  the  rays  more  completely  it  is  recommended  to  add  the 
lens  H,  immediately  in  front  of  G,  which  throws  an  image  of 
D  on  the  illumination  lens  J  ;  but  A  and  B  must  be  then  so 
centered  that  D  appears  uniformly  illuminated.  By  turning 
the  slit  tube  C  D  any  desired  part  of  the  spectrum  may  be 
thrown  into  the  polarization  apparatus,  but  A  and  B  must  be 
attached  in  fixed  position  with  reference  to  this  tube  ;  on  ac- 
count of  its  small  dimensions  and  slight  weight  the  Linnemann 
zircona  light  burner  (§142)  is  recommended  for  this  work. 
If  one  employs  sunlight  a  small  movable  mirror  is  attached  in 
place  of  A,  by  aid  of  which,  with  the  different  positions  of  the 
slit  tube,  the  heliostat  light  may  be  thrown  directly  into  the 
tube.  According  to  Lippich  the  direct  vision  spectrometer  of 
Hilger,  in  London,  with  the  Christie  half-prism1  is  also  very 
satisfactory,  as  with  this  the  simple  turning  of  the  prism  is 
sufficient  to  bring  any  desired  part  of  the  spectrum  to  the  slit 
G.  The  whole  spectroscope,  C  to  G,  must  first  be  graduated 
according  to  wave-lengths,  in  order  to  be  able  to  give  directly, 
for  any  position  of  C  D,  the  mean  wave-length  of  the  light 
passing  the  slit  G.  For  this  purpose  the  slit  C  is  illuminated 

1  Proc.  Roy.  Soc.,  »6,  8  (1878)  ;  Pogg.  Ann.  Beibl.,  i,  556  (1877). 


LOMMEL'S  METHOD  427 

with  the  several  homogeneous  lights  described  in  the  last  para- 
graph, one  after  the  other,  and  the  tube  C  D  is  turned  so  that 
the  image  of  the  illuminated  slit  C  coincides  exactly  with  G, 
which  may  be  easily  verified  by  aid  of  a  reading  glass.  The 
different  positions  of  the  tube  C  D  are  read  off  on  the  gradu- 
ated circle,  and  are  tabulated  along  with  the  corresponding 
wave-lengths  of  the  homogeneous  light.  In  this  way  a  large 
number  of  definite  positions  of  the  tube  C  D  are  determined 
for  which  accurately  characterized  homogeneous  colors  pass 
through  the  slit  G,  and  the  angles  of  rotation  of  these  may 
then  be  measured  with  the  polarimeter  in  the  usual  manner. 
In  the  graduation  of  the  spectrum  apparatus  the  Fraunhofer 
lines  of  sunlight  may  of  course  be  used.  The  greater  the  dis- 
persion the  smaller  must  be  the  slits  C  and  G,  in  order  that 
the  light  emerging  from  G  may  have  the  necessary  homogene- 
ity. If,  finally,  the  rotation  dispersion  is  very  large,  the  Lip- 
pich  method  is  then  no  longer  applicable,  since,  in  this  case,  a 
slit  so  narrow  would  be  required  that  the  necessary  brightness 
of  the  field  could  not  be  secured  ;  it  is  then  better  to  apply  the 
procedure  of  Broch  or  v.  Lang. 

Agreeing  in  principle  with  the  Lippich  method  is  that  of 
Seyffart,1  patented  in  1886,  for  the  determination  of  rotation 
dispersion.  But  as  the  latter  is  very  complicated  as  regards 
the  optical  as  well  as  the  mechanical  construction,  without,  at 
the  same  time,  reaching  the  accuracy  of  the  Lippich  method, 
it  need  not  be  discussed  here  at  length.  The  spectrosaccharim- 
eter  introduced  recently  by  Glan2  resembles  also  the  Lippich 
apparatus  in  principle,  but  is  much  inferior  to  it  as  regards 
convenience  or  accuracy  in  manipulation. 

157.  Lommel's  Method. — Lommel"  has  so  modified  the  Broch 
method  by  addition  of  a  quartz  wedge  that  the  final  reading  is 
made,  as  in  the  case  of  the  Wild  polaristrobometer  (§103),  on 
the  disappearance  of  interference  bands.  Sunlight  is  polarized 
by  the  prism  A  (Fig.  73),  whose  principal  section  makes  an 
angle  of  45°  with  the  horizontal  plane,  and  then  reaches  the 
vertical  slit  D.  Just  in  front  of  this  slit  is  a  quartz  wedge  C, 

i  Seyffart:  Wied.  Ann.,  41,  113  (1890). 

-  Glan:  Ibid.,  43,  441  (1891). 

5  Lommel  :  Ibid.,  36,  731  (1889). 


428  DETERMINATION   OF    ROTATION   DISPERSION 

with  an  angle  of  7°  or  8°,  whose  edge,  parallel  to  the  optical 
axis,  is  vertical  with  reference  to  the  slit,  and  immediately  fol- 
lowing the  latter  is  the  analyzer  E,  the  principal  section  of 
which  either  crosses  or  stands  parallel  with  the  principal 
section  of  the  polarizer  and,  therefore,  makes  an  angle  of  45° 
with  the  horizontal  plane.  The  refractive  action  of  the  wedge 
is  corrected  by  that  of  a  glass  wedge,  B,  placed  in  reversed 
position.  The  light  leaving  the  analyzer  is  decomposed  by 
the  prism  F,  which  is  placed  in  the  position  of  minimum 


H 

Fig.  73- 

deviation,  and  is  then  collected  by  the  achromatic  lens  G  to 
form  a  spectrum  that  may  be  observed  by  the  ocular  H.  As 
readily  understood,  this  spectrum  is  filled  with  numerous 
dark,  somewhat  curved,  interference  bands  which  stand  inclined 
with  reference  to  the  Fraunhofer  lines,  and  it  is  also  shaded 
by  fine  dark  slanting  lines.  If  the  polarizer  A  is  turned 
through  45°,  the  shading  disappears  through  the  whole  spec- 
trum (the  zero-point).  If  now  an  active  body  is  placed  be- 
tween A  and  B  the  bands  appear  again.  If,  next,  the  polar- 
izer be  rotated,  a  position  is  found  at  which  a  vertical  bright 
band,  free  from  shade,  enters  the  field  of  view  and  with 
further  turning  travels  through  the  spectrum.  By  bringing 
this  bright  band  to  coincide  with  the  various  Fraunhofer  lines, 
one  after  the  other,  so  that  each  line  bisects  the  band  exactly, 
and  the  corresponding  angle  is  then  read  off  on  the  graduated 
circle  of  the  polarizer,  the  angle  of  rotation  of  the  particular 
Fraunhofer  line  is  obtained.  The  Lommel  method  may,  of 
course,  be  so  arranged  that,  as  in  v.  Lang's  method,  artificial 
sources  of  light  may  be  used. 

Reference  only  can  be  made  here  to  Lommel' s  interesting 
determination  of  the  rotation  dispersion  of  quartz  by  aid  of 
the  interference  phenomena  on  a  quart/  prism.1 

1  Wied.  Ann..  36,  733  (1889). 


LAXDOLT'S   METHOD  429 

158.  Landolt's  Method  with  Use  of  Ray  Filters.— While  the 
methods  thus  far  described  for  the  measurement  of  rotation 
dispersion,  necessitate  the  use  of  apparatus  which  is  compli- 
cated for  the  chemist  if  not  for  the  physicist,  since  the  com- 
bination of  a  spectrometer  with  a  polarimeter  is  always  called 
for,  that  of  Landolt1  with  ray  filters  requires  the  use  of  a 
polarimeter  only.  It  may  always  be  recommended,  therefore, 
because  of  its  convenience  where  the  greatest  accuracy  is  not 
required,  and  where  the  angles  of  rotation  remain  below  100°. 
In  the  Landolt  method,  ordinary  white  light  is  used,  and  by 
aid  of  proper  absorbing  media  all  colors  are  removed,  within 
rather  narrow  limits,  except  the  one  desired,  which  depends, 
of  course,  on  the  nature  of  the  absorbing  substance  employed. 
If  now,  rotation  measurements  are  made  with  these  rather 
homogeneous  colors,  the  rotations  found  must  correspond, 
according  to  §147,  with  some  definite  optical  center  of  gravity, 
which  depends  simply  and  alone  on  the  relative  distribution  of 
brightness  in  the  spectrum  of  the  color  in  question,  assuming 
that  the  rotations  are  measured  by  a  Lippich  instrument,  and 
that  the  active  substance  absorbs  all  wave-lengths  of  this  color 
uniformly.  Therefore,  since  the  optical  center  of  gravity  is 
determined  by  the  source  of  white  light,  and  the  absorbing  media, 
and  changes  with  both,  the  directions  given  by  Landolt  for  pre- 
paring the  ray  filters  must  be  followed  with  the  greatest  exactness 
if  the  measurements  of  different  observers  are  expected  to  be  com- 
parable  with  each  other.  If  modifications  are  adopted,  the  new 
optical  center  must  certainly  be  defined  and  measured.  The 
Welsbach  lamp  serves  as  a  source  of  white  light  for  these  ray 
filters,  and  as  absorbing  media  solutions  of  only  such  sub- 
stances are  employed  as  are  found  in  commerce  in  sufficiently 
pure  condition.  The  solutions  are  filled  into  cylindrical  glass 
cells  of  about  4  cm.  diameter  which  consist  of  rings  with  plane 
glass  plates  cemented  to  them.  One  style  of  cell  contains  two 
compartments,  each  having  an  internal  thickness  of  20  mm., 
while  another  style  has  three  divisions  of  20,  15,  and  15  mm. 
thickness.  Each  compartment  is  supplied  with  an  opening, 
which  may  be  closed  with  a  glass  stopper,  and  which  permits 

1  Landolt :  Sitzungsber.  d.  Akad.,   Berlin,   1894,   p.   923  ;  Her.  d.  chem.  Ges.,  27, 

2S72  (1894). 


430  DETERMINATION   OF   ROTATION    DISPERSION 

the  filling  with  the  solutions.  The  cells  may  be  shoved  into 
a  metallic  framework  having  square  plates  on  the  corners  to 
prevent  rolling.  These  ray  filters1  are  always  to  be  placed  be- 
tween the  source  of  light  and  the  illumination  lens  of  the  appa- 
ratus, and  the  zero  point  must  always  be  found  after  they  are 
placed  in  position.  It  should  be  determined  anew  for  each 
ray  filter,  even  when  the  half-shadow  of  the  instrument  has 
not  been  changed  (see  §106).  The  five  filters  permit  red, 
yellow,  green,  light  blue  and  dark  blue  to  pass. 

Red. — In  the  production  of  this  color,  the  hydrochloride  of 
hexamethylpararosaniline  is  used,  which  comes  into  commerce 
under  the  name  of  crystal  violet  5  B  O,  and  the  anhydrous  can- 
tharides  green  crystals  must  be  selected.  If  0.05  gram  of  this 
be  dissolved  first  in  a  little  alcohol  and  then  diluted  with  water 
to  one  liter,  this  solution  filled  into  a  cell  20  mm.  deep  gives  a 
spectrum  which  consists  of  a  red  band  and  a  broad  blue  violet 
part.  The  latter  may  be  completely  absorbed  by  adding  a  layer 
of  yellow  potassium  chromate  solution  20  mm.  thick,  and  con- 
taining 10  grams  in  100  cc.  The  red  band  now  remaining 
begins  with  the  wave-length  about  718  w,  and  ends  sharply 
at  639  w*.  The  half-shadow  of  the  instrument  may  be  as 
small  as  about  3°. 

Yellow. — A  solution  of  30  grams  of  crystallized  nickel  sul- 
phate in  loo  cc.,  in  a  layer  of  20  mm.  thickness,  absorbs  only 
the  red  rays  and  permits  all  others  to  pass.  If  a  cell  15  mm. 
deep  is  added,  containing  potassium  monochromate  solution 
with  10  grams  in  100  cc.,  the  blue  and  violet  are  taken  out, 
leaving  only  orange-yellow  and  green.  The  last  of  these  colors 
may  be  absorbed  by  means  of  a  potassium  permanganate  solu- 
tion containing  0.025  gram  in  100  cc.,  and  used  in  a  15  mm. 
layer.  The  spectrum  is  now  reduced  to  a  narrow  orange- 
yellow  band  which  still  shows  a  little  red  light  and  embraces 
the  wave-lengths  from  614  nv  to  574  W.  As  the  three 
absorption  solutions  weaken  the  light  materially,  it  is  neces- 
sary to  employ  a  half -shadow  of  8°  to  10°. 

Green. — For  this,  a  combination  of  potassium  monochromate 
with  cupric  chloride  is  used.  A  solution  of  60  grams  of 
CuCl,  -f-  2H,O  to  100  cc.  in  a  20  mm.  layer  allows,  practically, 

i  Obtainable  from  Schmidt  and  Haensch,  Berlin. 


LANDOLT'S  METHOD  431 

only  green  and  blue  rays  to  pass.  The  last  may  be  absorbed 
by  a  20  mm.  layer  of  a  potassium  monochromate  solution  con- 
taining i  o  grams  in  ioocc.,  and  there  remains  then  abroad 
green  band  on  the  edge  of  which  there  is  still  a  little  blue. 
This  band  embraces  the  wave-lengths  from  540^^  to  505^. 
The  half-shadow  must  amount  to  3°  or  more. 

Light  Blue. — In  the  production  of  this  color  there  is  used 
the  compound  known  in  commerce  as  double  green  S  F,  which 
is  a  combination  of  chlormethylhexamethylpararosaniline  hy- 
drochloride  with  zinc  chloride,  and  which  appears  as  a  glit- 
tering bronze-colored  powder.  An  aqueous  solution  of  0.02 
gram  of  the  color  to  100  cc.  gives  in  a  20  mm.  layer  a  spec- 
trum consisting  of  a  narrow  red  band  with  a  broad  green 
and  a  light  blue  part  ;  the  dark  blue  is  absorbed.  With  a  blue 
vitriol  solution  containing  15  grams  in  100  cc.  in  a  20  mm. 
layer,  the  red  band  may  be  absorbed,  but  it  is  not  possible  to 
so  remove  the  green  light  that  light  blue  of  sufficient  intensity 
alone  remains.  The  light  left  is,  therefore,  a  combination  of 
green  rays  of  wave-lengths  526 yu/u  to  about  494/1^,  and  of 
light  blue  rays  from  494.;^  to  458^.  Asa  result,  no  uniform 
color  is  found  in  the  field  of  view  of  the  polarization  instru- 
ment, but  the  change  of  shade  on  turning  the  analyzer  to  and 
fro  may  still  be  followed.  The  half-shadow  may  be  reduced 
to  about  3°. 

Dark  Blue. — This  color  is  obtained  by  a  combination  of 
solutions  of  crystal  violet  5  B  O,  with  0.005  gram  in  100  cc. 
and  blue  vitriol  with  15  grams  in  100  cc. ,  both  used  in  cells  20 
mm.  deep.  The  last  solution  absorbs  the  red  rays  which  the 
aniline  color  passes  a,nd  there  remains  only  dark  blue  light  of 
wave-lengths  478  to  410^^.  Because  of  the  low  intensity  of 
the  light,  a  half -shadow  of  about  8°  must  be  taken. 

The  absorption  solutions,  with  the  exception  of  the  per- 
manganate, are  permanent,  but  it  is  advisable  to  keep  the 
supply  of  the  aniline  colors  in  the  dark,  and  to  renew  the  fill- 
ing in  the  cells  holding  them  from  time  to  time.  But  the  per- 
manganate solution  must  be  freshly  prepared,  since  it  easily 
suffers  decomposition. 

As  the  rotation  dispersion  of  quartz  is  pretty  accurately 
known,  the  optical  centers  of  gravity  of  the  five  colors  from 


432 


DETERMINATION    OF    ROTATION    DISPERSION 


the  ray  filters  may  be  found  by  the  aid  of  quartz  plates, 
according  to  §148.  Landolt  has  done  this  and  has  found  that 
the  five  optical  centers  are  near  the  Fraunhofer  lines,  C,  D,  E, 
F,  and  G.  The  following  table  shows  the  exact  values  : 


Color  filter. 

Optical  center  of 
gravity  in  /K/U.. 

Fraunhofer's  lines. 

Wave-lengths  in  /u/u. 

Red  =  nf 

Yellow  =yl 
Green  —  gr 
Light  blue  =  Ib 
Dark  blue  =  db 

665.9 

591-9 

533-0 
488.5 
448.2 

C 
D 
E 
F 
G 

656.3 
589.3 
527.0 
486.1 
430.8 

These  relations  then  obtain  for  the  rotations  a  with  quartz 

plates:  .032  «„  =  «,: 

.010  otyf  =  aD 

.026   OLsr—  OtE 
.Oil    Otlt>  =  Otp 

-091  adb=  aG 

By  aid  of  these  equations  it  is,  therefore,  possible  to  reduce 
rotations  found  by  the  ray  filter  method  to  those  which  obtain 
for  the  corresponding  Fraunhofer  lines,  and  this  may  always 
be  done  if  the  active  substance  has  about  the  same  rotation 
dispersion  as  quartz. 

The  following  table  contains  the  data  showing  the  prepara- 
tion of  the  filter  solutions,  along  with  their  optical  centers  of 
gravity  and  the  corresponding  rotations  for  i  mm.  of  quartz  at 
20°  C. 


Color. 

lug 
I** 
JV 

Aqueous  solutions  of 

Grams  of 
substance 
in  100  cc. 
of  sol. 

Sfci 
'•5,s  =*- 
o8.2 

%i\ 

3H  o" 

*°° 

Red 

20 
20 

Crystal  violet  5  B  O 
Potassium  monochromate 

0.005 
10 

665.9 

16.78° 

Yellow 

20 
15 
*5 

Nickel  sulphate,  NiSO4  -f  7  aq 
Potassium  monochromate 
Potassium  permanganate 

30 
10 

0.025 

591-9 

21.49° 

Green 

20 
20 

Copper  chloride,  CuCl.2    •    2  aq 
Potassium  monochromate 

60 

10 

533-0 

26.85° 

Light  blue 

20 
20 

Double  green  S  F 
Copper  sulphate,  CuSO4  -f  5  aq 

0.02 
15 

4885 

32.39° 

Dark  blue 

20 
20 

Crystal  violet  5  B  O 
Copper  sulphate,  CuSO4  -f  5  aq 

0.005 
15 

448.2 

39-05° 

ARONS-LUMMER   MERCURY   LAMP 


433 


159.  The  Arons-Lummer  Mercury  Lamp. — The  simplest  method  of 
determining  rotation  dispersion  would  be  by  aid  of  the  Lippich 
half-shadow  apparatus,  if  one  had  the  means  of  producing  a 
sufficiently  large  number  of  homogeneous  lights  of  different 
wave-lengths.  In  §155  wre  have  referred  to  a  number  of 
sources  of  homogeneous  light  besides  sodium  light,  but  they 
all  have  this  disadvantage  that  their  luminosity  is  too  slight  to 
make  accurate  observations  possible.  But,  as  a  matter  of  fact, 
since  there  is  need  of  homogeneous  lights  of  great  intensity  for 
polarimetric  work  it  may  be  safely  assumed  that  before  long 
this  want  will  certainly  be  supplied.  This  end  might  be 
reached,  for  example,  just  as  du  Bois  produced  an  intense  so- 
dium light  (§146),  by  forming  similar  pencils  of  salts  of  other 
metals  as  lithium,  thallium,  potassium,  strontium,  etc.  It 
would  be  a  great  advance  to 
secure  a  sufficiently  bright 
cadmium  light,  since  accord- 
ing to  Michelson1  the  four 
lines  found  in  the  red,  green, 
and  blue  portions  of  the  spec- 
trum (643.8,  508.6,  480.0, 
467.8  /^)  have  an  extremely 
constant  optical  center  of 
gravity.  At  the  present  time 
we  have,  in  addition  to  the 
sodium  light,  only  one  other 
source  of  homogeneous  light  of  great  intensity,  and  this  is  the 
Arons  mercury  light. 

The  mercury  lamp  constructed  by  Arons2  and  improved  later 
by  Lummer,3  is  shown  in  Fig.  74.*  The  cylindrical  tube  B, 
with  plane  ends  s,  is  connected  near  the  middle  with  the  two 
short  vertical  tubes  A  and  C,  which  are  closed  below  and 
furnished  with  platinum  wires  m  and  n,  fused  into  the  glass  ; 
a  small  tube  is  fused  to  B  at  r.  The  tubes  ABC  are  cleaned 
and  dried,  A  and  C  are  filled  with  mercury,  r  is  drawn  out, 

1  Traveaux  et  mgmoires  du  bureau  international  des  poids  et  mesures,  Tome,  XI, 
Paris  (1895).     Michelson,  Jour,  de  Phys.,  [3],  3,  5  (1894). 

2  Arons:  Wied.  Ann.,  47,  767  (1892). 

•'•  I<ummer:  Ztschr.  fur  Instrum.,  15,  294  (1895). 
4  From  Muencke,  Berlin. 
28 


Fig.  74- 


434  DETERMINATION    OF    ROTATION    DISPERSION 

and  then,  after  exhaustion  of  B  by  a  mercury  pump,  is  sealed 
by  melting.  If  a  current  from  about  thirty  storage  cells  is  led 
through  m  and  n  into  A  and  B,  and  temporary  contact  is  made 
by  shaking  the  mercury,  the  arc  light  of  this  metal  is  produced 
which  continues  to  play  quietly  after  the  apparatus  is  brought 
to  rest  with  B  in  horizontal  position.  The  whole  section  of  B 
is  filled  with  a  very  intense  grayish  white  light,  which,  diffused 
from  the  matted  walls  of  the  tube,  shines  freely  through  the 
end  surfaces  s,  and  is  the  brighter  the  stronger  the  current 
employed.  If  currents  up  to  10  amperes  are  used  the  glass  at 
the  contacts  m  and  n  must  be  protected  from  overheating. 
This  is  provided  for  by  the  little  vessels  D  and  E  melted  on  to 
the  lower  ends  of  A  and  C,  and  which  are  likewise  filled  with 
mercury,  so  that  the  platinum  wires  m  and  n  dip  into  this 
metal  on  each  side.  The  current  is  led  to  the  mercury  by  wires 
extending  through  the  little  tubes  fused  to  the  sides  of  D  and 
E.  As  the  tube  B  becomes  very  warm  at  the  point  where  the 
arc  is  formed,  if  the  current  is  at  all  strong,  and  may  be  broken 
through  this  heating  effect,  it  must  be  furnished  with  a  water- 
jacket  to  control  the  temperature  and  prevent  cracking,  which 
may  be  done,  as  shown  in  the  figure,  by  leading  water  in  at  p 
and  out  at  q.  The  two  ends  of  the  tube  B  project  beyond  the 
water-jacket,  in  order  that  the  mercury,  which  vaporizes  in 
large  quantity,  may  not  collect  on  the  surfaces  s,  but  on  the 
side  walls  of  B  ;  a  constant  variation  in  the  intensity  of  the 
light  is  thus  avoided.  A  current  of  from  2  to  20  amperes  may 
be  sent  through  the  lamp  protected  in  this  way  by  flowing 
water  without  running  a  risk  of  breaking  it. 

In  spite  of  the  appearance  of  continuity  in  the  light  arc  the 
discharge  is  a  discontinuous  one.  This  accounts  for  the  fact 
that  notwithstanding  the  low  tension  of  about  1 7  volts  at  the 
mercury  electrodes  an  electromotive  force  of  at  least  three 
times  this  is  required  to  produce  the  arc.  The  arc  exhibits  a 
line  spectrum  of  extraordinary  strength.  But  only  a  few  lines 
are  important  for  polarimetry.  The  line  546.1  j^v,  in  the  yel- 
lowish green  is  remarkably  strong.  If  it  is  desired  to  illumi- 
nate the  polarization  apparatus  with  this  light,  it  must  of  course 
be  separated  from  light  of  all  other  wave-lengths  produced  at 
the  same  time,  which  may  be  best  accomplished  by  the  method 


ARONS-LUMMER    MERCURY    LAMP  435 

•of  spectrum  purification  explained  in  §149.  Two  rather  bright 
lines  are  found  in  the  yellow  with  wave-lengths  579.0  and 
576.9  ///*  ;  as  these  lie  so  close  together  a  very  great  dispersion 
must  be  employed  if  they  are  to  be  actually  separated  and  used 
in  polarimetric  measurements.  But  there  is  really  no  need  of 
this,  as  in  the  immediate  neighborhood  of  these  lines  the  much 
stronger  sodium  lines  are  found.  Finally  the  blue  line,  435.9 
A*/*,  of  the  mercury  arc  light  may  be  used  ;  but  as  this  is  rather 
dark  a  large  half-shadow  angle  must  be  taken  so  that  the 
measurements  made  are  not  very  accurate.  From  the  above 
it  is  seen  that  the  line  in  the  yellowish  green,  546.  i  £t//,  is  the 
only  one  applicable  in  polarimetry. 

As  regards  the  constancy  of  the  optical  centers  of  gravity  of 
the  brighter  spectrum  lines  formed  by  the  mercury  lamp  one 
must  stand  in  a  skeptical  attitude  until  fuller  data  are  pub- 
lished concerning  them.  The  spectrum  of  this  light  is  made 
up  of  a  remarkably  large  number  of  lines  ;  Arons  has  deter- 
mined no  fewer  than  32  lines  between  623  and  404  nn.  It  is, 
therefore,  hardly  possible  in  polarimetric  measurements  to  so 
far  purify  the  four  brighter  lines  mentioned  above  that  light 
of  adjacent  lines  may  not  also  enter  the  apparatus.  It  follows, 
therefore,  as  w^e  know  from  §147,  that  the  optical  centers  cor- 
responding to  measured  angles  of  rotation  can  scarcely  be 
stated  with  satisfactory  accuracy.  Near  the  brightest  line 
found  in  the  yellowish  green,  546.  i  nj*,  there  are  found,  for 
-example,  six  other  lines  in  the  immediate  neighborhood,  and 
these  have  the  wave-lengths  548,  545,  543,  537,  536,  and  532 
yw/<.  The  resulting  optical  center  must  vary,  therefore,  with 
the  degree  of  dispersion  employed  in  the  spectral  purification 
of  the  light.  Furthermore,  this  center  may  change  with  the 
strength  of  current  sent  through  the  lamp,  as  it  can  hardly  be 
assumed  that  the  brightness  of  all  the  different  lines  increases 
in  the  same  proportion  (see  also  §150).  In  addition  to  this 
it  appears,  according  to  the  statements  of  Arons,  that  with 
longer  burning  of  the  lamp  the  whole  spectrum  from  about 
543  to  503  yw;<  becomes  of  a  dull  green  color,  so  that  changes  of 
the  optical  center  with  time  are  not  impossible. 


436  POLARIZATION   TUBES 

B.   CONSTRUCTION  OF  THE  POLARIZATION  TUBES  AND  THE 

MEASUREMENT  OF  THEIR  LENGTH. 

160.  Construction  of  the  Tubes  and  Method  of  Closing  Them  by  End 
Plates  of  Glass. — The  tubes  used  with  polarization  instruments 
should  always  be  made  of  glass.  If  in  special  investigations 
it  is  necessary  to  employ  metal  tubes,  these  should  have  a 
matted  gold  finish  inside  ;  but  they  have  this  drawback,  that 
changes  of  length  with  temperature  are  much  greater  than 
with  glass  tubes.  The  tubes  are  commonly  made  2  dm.  in 
length,  but  shorter  ones  down  to  i  dm.  and  longer  ones  up  to 

1  meter  are  in  use.     The  inner  diameter   varies  between  6  and 
12  mm.,  and  the  thickness  of  the  walls  should  be  about  2  mm. 
As  shown  in  §p<5,  the  polarization  tubes  should  have  an  internal 
diameter  about  3  mm.  greater  than  the  polarizer  and  analyzer 
diaphragms  of  the  instrument;  if  they  have  not,  the  latter  should 
unquestionably  be  decreased.     The  ends  of  the  tubes  are  care- 
fully ground  off  plane,   and  care  must  be  taken  to  have  the 
two  polished  surfaces  parallel  to  each  other  and  vertical  to  the 
axis  of  the  tube.     The  angle  formed   by  the   two  ground  sur- 
faces should  be  always  below   10'.     For  tubes  not  more  than 

2  dm.  in  length  this  angle  may  be  measured  very  conveniently 
and  accurately  by  aid  of  the  Abbe  spectrometer.1     If  the  angle 
is  of  considerable  size,   it  may   be  recognized  in  the  following 
manner  :  The  observation   tube,   filled  with  water,   is  closed 
with  plane  parallel  cover  glasses,  placed  in  the  polariscope  and 
brought  into  focus  with  the  telescope.     If  the  tube  is  now 
rotated  on  its  axis  the  field  of  view  changes  in  shade  if  this 
angle  is  large. 

The  tubes  are  closed  always  with  plane  parallel  glass  plates. 
To  accomplish  this,  each  end  of  the  tube  is  supplied  with  a 
brass  setting  on  which  a  cap  with  a  diaphragm  may  be 
screwed  and  this  serves  to  press  the  glass  plate  against  the 
end  of  the  tube.  As  the  cover  glasses  should  lie  on  the  ends 
of  the  glass  tubes  only,  the  latter  should  project  a  trifle 
beyond  the  brass  setting  ;  the  wedge-angle  of  the  cover  glasses 
should  not  exceed  ^  ;  the  exact  angle  may  be  measured  by  the 
Abbe  spectrometer  as  before.  In  order  to  prevent  too  great  a 
pressure  on  the  cover  glasses  when  they  are  pressed  home  by 

1  See  Kohlrausch  :  Praktische  Physik.,  1896,  p.  178. 


CONSTRUCTION   OF   THE   TUBES  437 

the  screw  cap,  a  ring  of  rubber  or  soft  leather  is  placed  between 
the  glass  and  the  cap.  But,  notwithstanding  this,  the  cover 
glass  must  not  be  pressed  too  hard,  because  double  refraction  in 
the  glass  may  follou' through  pressure,  and  this  will  destroy  the 
uniformity  of  the  Jield,  and  may  easily  give  rise  to  a  zero-point 
displacement  in  the  instrument,  amounting  to  several  minutes. 
As  furthermore,  without  application  of  pressure  and  on 
account  of  internal  strains  in  the  glass,  rotations  of  a  minute 
or  more  may  be  caused  by  the  cover  plates,  it  is  necessary  in 
all  accurate  work  to  give  very  particular  attention  to  the 
character  of  these  plates  ;  in  saccharimetery,  the  cover  glasses 
alone  may  lead  to  errors  of  several  tenths  of  a  Ventzke  degree. 
Krrors  may  be  wholly  avoided  by  noting  first  the  reading  with 
the  empty  tube  and  cover  glasses  in  place,  and  then  of  the 
tube  filled  through  a  side  opening  with  the  liquid  to  be  investi- 
gated ;  by  subtracting  the  first  reading  with  its  proper  sign 
from  the  second,  the  correct  result  is  reached. 

To  exclude  the  possibility  of  making  the  cover  glasses 
optically  active  by  too  strong  pressure  on  the  screw  cap,  obser- 
vation tubes  with  the  Landolt  closing  device  are  now  very  fre- 
quently used.  With  this  the  glass  plates  are  not  pressed 
against  the  tube  by  the  motion  of  the  screw  cap,  but  by  means 
of  a  cap  held  down  by  a  spring. 

In  the  investigation  of  beet- juices,  the  Pellet  tube1  for  con- 
tinuous polarization,  shown  in  section  in  Fig.  75,  is  frequently 

used.       It  is   commonly 

1 1 R  'i  i  i-i 

made  of  metal,  is  closed  a    osjj^ 

at  A  with   inside  screw 


caps,  and  at  each  end  has  A  A" 

a  side  tube  entering  near 

the  glass  cover  plates.  A  funnel  is  attached  to  one  of 
these  tubes  and  to  the  other  a  piece  of  rubber  tubing  with 
properly  bent  glass  tube,  so  that  the  solution  at  any  time  in 
the  polarization  tube  may  be  completely  forced  out  by  the 
pressure  of  fresh  liquid  poured  into  the  funnel.  In  this  way, 
a  great  many  polarizations  may  be  rapidly  carried  out  in  the 
same  tube,  one  after  the  other  ;  but  the  actual  observation 

1  Pellet :  Ztschr.  fiir  Riibenzucker-Ind.,  41,  338  (1891).     The  tubes  may  be  obtained 
from  Schmidt  and  Haensch. 


438  POLARIZATION   TUBES 

must  not  be  made  until  the  old  contents  of  the  tube  are 
fully  expelled  by  the  new,  which  is  the  case  when  the  cloudy 
striations,  noticed  at  first,  have  completely  disappeared. 

When  the  telescope  is  focused  after  putting  a  filled  obser- 
vation tube  in  the  instrument,  the  field  of  view  must  be 
sharply  and  uniformly  clear  throughout  its  whole  extent,  the 
outside  edge  and  the  dividing  lines  of  the  fields  as  well ;  only 
when  this  is  the  case  is  it  proper  to  begin  the  observations.  If 
the  adjustment  does  not  remain  sharp  on  turning  the  tube  it 
shows  either  that  the  solution  was  not  homogeneous  or  that 
the  tube  was  not  clean. 

If  qualitative  observations  only  are  to  be  made,  glass  troughs, 

as  shown  in  Fig.  76,  may  be 
recommended.1    The  cover, 
furnished    with   a    button, 
may  be  taken  off,  while  the 
other  parts  are  fastened  to- 
gether with  easily  fusible  glass.    These  troughs  may  be  placed 
in  the  gutter  h  (Fig.  45)  of  the  Lippich-Landolt  apparatus. 

161.  Water-jacket  Tubes  and  Water-Heating  Apparatus. — Tubes 
furnished  with  instruments  do  not  ordinarily  have  a  water- 
jacket  ;  the  contained  liquid  is,  therefore,  exposed  to  the  pre- 
vailing air  temperature.  But  as  the  room  temperature  is  vari- 
able to  the  extent  of  at  least  ±3°,  and  as  the  rotating  power 
of  most  substances  is  largely  modified  by  heat,  it  is  necessary 
in  all  accurate  measurements  to  control  the  temperature  of  the 
liquid  during  the  observations.  This  may  be  done  by  sur- 
rounding the  glass  tube  with  a  brass  jacket  3  to  5  cm.  in  diam- 
eter and  allowing  a  current  of  water  to  flow  through  the  space 
between,  the  water  having  previously  been  brought  to  the  de- 
sired temperature  in  a  reservoir.  A  jacketed  tube  is  shown  in 
Fig.  77.*  The  tube  proper  consists  of  glass  and  to  the  middle 
of  it  is  fused  the  thermometer  tubulure  A,  which  at  the  same 
time  may  be  used  in  filling  the  observation  tube.  The  brass 
jacket  for  the  water  circulation  has  two  projecting  tubes,  B  and 
C,  which  serve  for  the  inflow  and  outflow  of  the  water.  After 
pouring  in  the  solution  the  tubulure  A  is  closed  with  a  ground 

'  From  I«eybold.  in  Cologne. 

1  From  Schmidt  and  Haensch,  Berlin. 


WATER-JACKET  TUBES  AND  HEATING  APPARATUS        439 

glass  stopper  D,  through  the  larger  central  opening  in  which 
a  thermometer  E  is  introduced.  This  thermometer  has  a  wide 
part  near  the  bottom  which  is  ground  to  fit  the  opening  air- 
tight. The  mercury  reservoir  of  the  thermometer  is,  there- 


fore, immersed  in  the  liquid,  and  it  must  project  so  far  into 
the  latter  that  its  lower  end  is  just  visible  in  looking  through 
the  observation  tube.  The  glass  stopper  D  has  a  second  open- 
ing at  one  side,  into  which  a  fine  glass  tube  is  cemented,  and 
to  this  a  bit  of  rubber  tubing,  F,  may  be  attached.  A  part  of 
the  air  in  A,  above  the  liquid,  escapes  through  this  when  the 
thermometer  is  inserted  ;  more  may  then  be  sucked  out  and  F 
closed  by  a  clamp.  The  thermometer  E  is  graduated  in  tenths, 
and  of  course  its  accuracy  must  be  determined  before  the  ob- 
servations. It  is  safest  to  have  the  thermometer  tested  by  the 
Physikalisch-Technischen  Reichsanstalt  at  Charlottenburg, 
and  corrected  say  from  5°-5°. 

A  water-heating  apparatus,  in  w7hich  the  water  to  flow 
through  the  jacket  of  the  observation  tube  is  brought  to  the 
right  temperature,  is  shown  in  Fig.  78.'  It  is  made  of  sheet 
zinc,  but  has  a  copper  bottom,  and  to  prevent  cooling  or  warm- 
ing by  the  air  is  covered  above  and  on  the  sides  writh  flannel. 
The  removable  cover  is  furnished  with  two  small  openings. 

l  From  Rohrbeck,  Berlin. 


440 


POLARIZATION    TUBES 


Through  one  of  these,  A, 
the  reservoir  may  be  filled 
with  water,  while  the  rod 
of  the  stirrer  works  through 
the  other.  This  latter  con- 
sists of  a  perforated  disk  fill- 
ing the  whole  section  of  the 
reservoir,  with  a  piece  cut 
out  at  the  right  point  to 
avoid  striking  the  ends  of 
the  thermometers  C,  bent 
at  right  angles  ;  the  rota- 
tion of  the  stirrer  is  pre- 
vented by  two  vertical 
guides  placed  on  the  inner 
walls  of  the  reservoir.  D 
is  a  glass  tube  to  show  the 
level  of  the  water,  and  E 
the  exit  tube,  with  a  stop- 
cock, which  may  be  con- 
nected with  the  water- jacket 
of  the  polarization  tube  by 
means  of  rubber.  A  second 
large  opening,  not  shown  in 
the  figure,  and  likewise  fur- 
nished with  a  stop-cock, 
serves,  when  necessary,  for 
the  rapid  discharge  of  the 
water.  The  reservoir  which 
is  supported  on  an  iron  stand 
may  be  warmed  by  means  of  a  Bunsen  burner  or  by  a  warm 
coil.  Before  beginning  an  observation,  water  is  allowed  to  flow 
about  fifteen  minutes  through  the  water-jacket  and  continued 
during  the  readings.  The  temperature  t,  which  is  the  mean 
of  all  the  readings  of  the  thermometer  in  the  polarization  tube 
during  an  observation,  is  then  that  temperature  to  which  all 
other  factors  must  be  reduced,  as  will  be  seen  by  the  following 
paragraph. 


Fig.  78. 


SCHMIDT   AND    HAENSCH    CONTROL   TUBE  441 

162.  Calculation  of  the  Specific  Rotation,   with  Consideration  of  the 
Effect  of  Temperature. — If  oc  is  the  angle  of  rotation  of  the  solu- 
tion of  an  active  substance,    /  the  length  of  the  observation 
tube,  p  the  percentage  strength,   and  d  the  specific  gravity, 

then,   according  to  §2,    the   specific  rotation  is   \oi\  ~-~rr~j- 

We  shall  write  this  equation  in  the  shorter  form  \_a~\  - 
/(<*,  I>  P>  dO»  tnat  is>  M  is  a  function  of  ex,  /,  /,  and  d.  With 
the  exception  of  p,  the  quantities  ex,  /,  and  d  are  variable  with 
the  temperature  /,  so  that  [or]  also  must  vary  with  /.  If  we 
express  this  dependence  on  the  temperature  by  the  index  /, 
then  \_a~\f  =f(crtj  lt,  p,  dt).  If  we  give  /  the  definite  value  /„ 
then  the  specific  rotation  for  the  temperature  t0  is  expressed 
properly  only  by  the  equation,  [or],0  =  /(/y,0,  /,„,/,  dtQ)  ;  the 
quantities  «,  /,  and  d  must  all  be  determined  for  the  tempera- 
ture, /0.  It  must,  therefore,  be  considered  as  absolute!}'  im- 
proper, as  is  unfortunately  often  the  case  to  find  a  and  /,  for 
example,  for  20°,  and  d  for  17.5°,  and  to  calculate  an  [a]  with 
these  values,  because  the  [or]  so  found  corresponds  naturally 
to  no  definite  temperature.  Now,  the  coefficients  of  expansion 
corresponding  to  /  and  d  are  easily  determined  (in  fact  are 
mostly  already  known),  so  that  /  and  d  may  be  readily  found 
for  any  temperature.  Therefore,  the  temperature  at  which  a  is 
measured,  is  the  one  which  must  be  taken  as  the  basis  for  the 
whole  calculation  of  [or] .  If  now  the  rotation  is  found  at  the 
temperature  /,,  («,),  then  /,,  and  d/t  must  be  calculated 
to  correspond,  and  finally  [or]^  —  /(«/a,  /^,  p,  dtl}\  in  this 
way  the  specific  rotation  for  the  temperature  /,  is  determined. 
If,  next,  a^  is  observed  in  the  same  manner,  we  obtain  [ar].,2 
—f(a'-2i  tf*>  P>  ^2)-  ^e  obtain  in  this  way  a  clear  idea  of  the 
dependence  of  [or]  on  /,  and  finally  after  calculating  the  tem- 
perature coefficient  of  \_ai] ,  we  are  able  to  reduce  all  the  ob- 
served values  of  [«]  to  one  and  the  same  temperature,  usually 
to  20°.  It  must  further  be  mentioned  that  the  specific  gravity 
is  always  referred  to  water  at  #°  ;  the  choice  of  any  other  tem- 
perature (o°  or  17.5°)  is  certainly  to  be  condemned,  since  water 
at  4°  is  the  basis  of  the  metric  system  of  iv eight. 

163.  Schmidt   and   Haensch   Control  Tube.— The  Schmidt  and 
Haensch  control  observation  tube,1  the  use  of  which  was  re- 

1  Schmidt  and  Haensch  :  Ztschr.  fur  Jnstrum.,  4,  169  (1884^. 


442  POLARIZATION   TUBES 

ferred  to  in  §128,  is  illustrated  by  Fig.  79.  The  tube  A  may  be 
moved,  in  telescope  fashion,  into  the  tube  B  which  it  fits  very 
accurately,  a  leather  washer  being  added  at  C  to  make  the 
joint  perfectly  tight.  The  ends  D  and  E  are  closed  by  the 
ordinary  screw  caps.  The  motion  of  the  tube  A  is  accomplished 
by  pinion  and  rack  mechanism  F  ;  on  the  latter  there  is  a  milli- 
meter scale  which  works  over  the  vernier  G,  attached  to  B, 
so  that  tenths  of  a  millimeter  may  be  read  off  directly.  The 
funnel  H,  which  is  detachable,  serves  to  take  up  the  excess  of 
liquid  expelled  on  contraction  of  the  tubes.  Instead  of  closing 


Fig.  79- 

the  tube  A  at  D  it  may  be  closed  at  the  other  end  at  J  by  screw- 
ing in  a  diaphragm  with  a  plane  parallel  glass  plate  ;  in  this 
arrangement  the  whole  tube  is  shorter  by  the  length  D  J,  than 
when  the  end  is  taken  at  D.  On  this  principle  (with  dia- 
phragm at  J)  tubes  may  be  constructed  whose  length  may  be 
decreased  to  zero.  For  saccharimeters  which  are  made  to  take 
in  very  long  tubes,  such  an  arrangement  would  be  very  ad- 
vantageous as  it  would  permit  a  determination  of  the  whole 
error  of  the  quartz  wedge  by  use  of  a  single  sugar  solution. 
For  the  ordinary  short  saccharimeters,  the  use  of  such  a  tube, 
which  may  be  shortened  to  zero,  is  not  to  be  recommended, 
since  the  determination  of  errors  is  less  accurate,  the  shorter 
the  tube  in  fully  extended  condition. 

It  may  be  remarked  regarding  the  practical  use  of  the  con- 
trol observation  tube,  that  the  solution  cannot  be  introduced 
through  the  funnel  H.  This  should  be  removed  and  the  ori- 
fice closed  by  the  metallic  stopper  furnished  with  the  tube. 
The  cap  E  is  removed,  the  tube  fully  extended,  and  then  the 


MEASUREMENT   OF    THE   TUBE    LENGTH 


443 


solution  is  poured  in.  After  filling  and  closing  E  the  tube  is 
brought  into  horizontal  position,  H  is  attached,  and  then  the 
tube  is  shortened  a  little  and  a  further  small  amount  of  liquid 
poured  into  the  funnel.  To  prevent  too  much  evaporation  it 
is  recommended  to  cover  the  latter  with  a  screw  top  which  has 
a  very  small  opening  to  permit  the  escape  of  the  air. 

164.  Measurement  of  the  Tube  Length.— 
The  statement  of  the  manufacturer  is 
commonly  taken  as  regards  the  length  of 
the  tube.  But  for  all  accurate  work  this 
length  must  be  known  with  certainty  to 
within  o.  i  mm. ,  and  it  is,  therefore,  de- 
sirable to  have  means  of  measuring  it 
one's  self.  A  measuring  instrument  de- 
signed by  lyandolt  for  this  purpose  is 
shown  in  Fig.  So.1  It  consists  of  a  me- 
tallic bar,  A,  divided  into  millimeters,  on 
the  lower  end  of  which,  at  a,  there  is  a 
sharp  knife  edge.  The  handle  c,  of  wood, 
may  be  fixed  at  any  point  desired.  The 
vernier  b,  provided  with  two  knife  edges, 
may  be  shoved  along  the  bar  with  a  little 
friction,  and  permits  a  reading  to  o.  i  mm. 
If  the  bar  A  is  placed  vertically  with  the 
edge  a  on  a  glass  plate  and  then  the  ver- 
nier is  shoved  down  until  its  two  edges 
rest  on  the  plate,  the  zero  point  on  the 
bar  and  the  zero  on  the  vernier  must 
agree,  so  that  the  reading  zero  is  thus 
given.  If  the  length  of  the  tube  B  is  to 
be  found,  one  end  is  closed  by  ^a  glass 
plate  and  screw  cap,  and  then,  in  vertical 
direction,  the  measuring  bar  A  is  shoved 
down  into  the  tube  until  the  edge  a 
touches  the  glass  at  the  bottom.  Then 
the  vernier  b  is  brought  down  until  its 
two  edges  touch  the  glass  tube  above, 
taking  care  that  the  bar  A  does  not  stand 

1  From  Schmidt  and  Haensch,  Berlin.  Fig.  80. 


A 


444  PERCENTAGE    STRENGTH    OF   SOLUTIONS 

inclined  in  the  tube.  The  length  is  then  read  off.  This  de- 
termination is  repeated  several  times,  the  tube  being  turned 
through  90°,  1 80°,  and  270°,  and  the  mean  of  all  taken.  If 
the  length  found  is  expected  to  be  actually  accurate  within  o.  i 
mm. ,  the  correctness  of  the  measuring  bar  must  be  previously 
determined,  and  above  all  the  temperature  of  the  bar  must  be 
considered.1 

In  all  cases  where  it  is  desired  to  know  the  tube  length  more 
accurately  than  to  o.  i  mm. ,  the  simplest  plan  is  to  have  the 
measurement  made  directly  in  the  Physikalisch-Technischen 
Reichsanstalt  at  Charlottenburg.  The  length  of  polarization 
tubes  may  be  there  accurately  found  by  aid  of  a  comparator  to 
within  o.oi  to  0.02  mm. 

If  the  angle  of  rotation  of  a  liquid  is  found  at  different  tem- 
peratures the  change  in  length  of  the  tube  must  be  taken  into 
consideration.  It  is  sufficient  for  this  purpose  to  consider  the 
linear  coefficient  of  expansion  of  glass  as  ft  =  0.000008  for  i°, 
and  for  brass  ft  —  0.000019.  If  the  length  of  the  tube  at  20° 
be  taken  as  4,o,  then  the  length  at  /°  is  found  from  the  equation, 
(I)  **>  ==*«>  + L*  ft  (t—  20). 

If,  for  example,  a  glass  tube  measures  exactly  200  mm.  at  20°, 
its  length,  according  to  this,  at  30°  is  200.016  mm.  The  cor- 
rection need,  therefore,  be  considered  only  with  long  tubes  and 
marked  temperature  changes. 

C.     DETERMINATION  OF  THE  PERCENTAGE     STRENGTH 
OF  SOLUTIONS 

165.  Reductions  of  Weighings  to  Vacuo. — The  determination  of 
the  percentage  strength  by  weighing  will  be  considered  in 
what  follows  in  such  a  manner  as  to  make  it  as  accurate  as 
possible.  If  for  special  purposes,  less  accuracy  is  called  for  in 
the  work,  the  procedure  may  naturally  be  easily  simplified. 
As  all  weighings  must  be  reduced  to  vacuo,  the  necessary  for- 
mulas will  first  be  stated.  It  must  be  assumed  that  these 
weighings  are  made  on  chemical  balances  which  permit  a  mass 
determination  which  is  accurate  to  about  dr  o.  i  mg. 

A  few  remarks  only  need  be  made  about  the  weighings  them- 

1  The   Physikalisch-Technischen  Keichsatistalt  at  Charlottenburg  makes  tests    of 
measuring  rods  and  determinations  of  their  errors  in  division. 


REDUCTIONS    OF   WEIGHINGS   TO    VACUO  445 

selves.  The  temperature  of  the  weights,  of  the  body  to  be 
weighed  and  of  the  air  in  the  balance  case,  should  differ  but 
little  from  the  air  temperature  of  the  room.  Do  not  place  a 
vessel  with  calcium  chloride  in  the  balance  case,  as  it  is  not 
possible  to  keep  the  air  in  the  latter  dry  during  the  time 
of  weighing  ;  at  most  the  calcium  chloride  may  be  used  as  a 
protection  against  rust  when  the  balance  is  not  in  use.  All 
weighings  should  be  made  by  the  method  of  vibrations,  with  a 
determination  each  time  of  the  zero  point  and  the  sensitiveness 
of  the  balance  ;  aside  from  its  greater  accuracy,  weighings  by 
the  vibration  method,  when  one  is  once  accustomed  to  it,  re- 
quire less  time  than  is  necessary  to  accurately  adjust  the  rider. 
It  is  necessary  to  determine  always  three  or  five  reversal  points. 
In  regard  to  a  determination  of  the  errors  in  the  set  of  weights 
it  is  only  necessary  to  compare  one  of  the  pieces  with  a  nor- 
mal set  of  weights  j1  the  errors  of  all  the  others  may  then  be 
found  from  this  with  sufficient  accuracy.  The  list  of  correc- 
tions should  be  pasted  on  the  balance  table,  and  at  each  weigh- 
ing the  sum  of  the  errors  in  the  weights  used  should  be  noted 
at  once.  Further  directions  may  be  found  in  Kohlrausch's 
"Praktische  Physik,"  1896,  41  to  53. 

In  the  reduction  of  the  weighings  to  vacuo,  the  density  of 
the  air  A.  (the  mass  of  i  cc.  in  grams)  at  the  time  of  weighing 
must  be  known.  The  density  of  the  air  is  a  function  of  the 
temperature  t  in  the  balance  case,  of  the  barometric  pressure, 
l\  in  millimeters  to  be  reduced  to  o°,  and  of  the  tension  e  of  the 
aqueous  vapor  in  the  air  : 

^  0.001293       £  —  0-375  e 

i  -f-  0.00367  t         760 

As  for  North  Germany  e  is  usually  between  3  and  15  mm.,  it 
is  sufficient  to  take  for  the  purpose  e  —  9,  so  that  we  have  then, 

(I)  \=        0.001293      £—3-4 

i  -f-  0.00367  /     760 

The  error  in  A.  occasioned  by  variations  in  e  amounts  in  the 
maximum  to  ±  0.000004.  If  tne  barometer  is  not  measured 
on  the  same  floor  where  the  weighing  is  made,  a  correction 
must  be  made  on  b,  since  b  decreases  o.  i  mm.  for  an  elevation 

1  The  Normal-Aichungscommission,  at  Berlin,  makes  such  comparisons. 


446  PERCENTAGE   STRENGTH   OF   SOLUTIONS 

of  i  meter.  If  /  is  observed  accurately  to  0.5°  and  bio  i  mm., 
then  by  aid  of  equation  (I)  the  air  density  A.  is  obtained  cor- 
rectly to  within  about  ±  0.000008.  In  the  mean,  A.  is  about 
0.00119  and  varies  between  the  limits  0.00113  and  0.00125. 

To  eliminate  the  error  due  to  inequality  in  the  arms  of  the 
balance,  the  body  whose  absolute  mass  is  to  be  found  is 
weighed  first  on  the  one  pan  and  then  on  the  other.  If  m^ 
and  m.,  are  the  weights  used  in  the  two  cases  to  hold  the  body 
in  equilibrium,  then  the  right  weight  of  the  body  in  the  air  is  : 

(II)  m=^±^. 

The  mass  so  found  is  then  to  be  reduced  to  the  vacuum  weight 
as  above.  If  s  is  the  density  of  the  body  and  6  the  density  of 
the  weights,  then  the  desired  mass  M  oi  the  body  in  vacuo  is 

M  —  m  -f-  m\  { — ) , 

\  s          0"  / 

or  in  better  form  for  computation 

(III)  M=m  +  mX(*^. 

Ordinarily  the  weights  are  of  brass,  for  which  a  =  8.4  may 
be  taken  ;  the  fact  that  the  smaller  weights  are  of  platinum  or 
other  foil  has  no  appreciable  effect  on  the  value  of  M.  With 
reference  to  the  densities,  s,  consult  Landolt  and  Boernstein's 
Tables,  1894,  P-  JI4  to  234,  from  which  \vith  the  numbers  on 

ff     o 

p.  10  the  values  for  A.  -      -  may  be  taken. 
ffs 

If  m  is  the  apparent  mass  of  the  body  in  the  air  of  density 
X,  and  m'  the  apparent  mass  of  the  body  in  air  of  density  A.', 
then  follows  from  equation  (III), 

(IV)  m'  =  m  +  m(\  —  A')  ^— -. 

(TS 

By  means  of  this  equation  it  is  possible  to  reduce  the  mass 
found  for  any  density  of  the  air  A.  to  any  other  density  A/. 

166.  Preparation  of  Solutions  by  Weighing. — For  this  purpose  it 
is  advisable  to  use  small  flasks  with  wide  neck  and  glass  stopper, 
having  a  capacity  of  20  to  150  cc.  (Fig.  81).  After  cleaning 
the  flask  with  water  and  rinsing  with  alcohol,  it  is  dried  by 


REDUCTIONS   OF   WEIGHINGS   TO   VACUO 


447 


forcing  air  for  a  long  time  through  it.     Then,    according  to 

the  last  paragraph   (II),   its  apparent  mass  m  in  the  air  of 

density  A.  will  be  found.     Next,  one  of 

the  components  A  of  the  solution   is 

introduced  into  the  flask  ;  if  a  definite 

quantity  of  A  is  to  be  taken  it  is  more 

convenient  to  use  a  coarse  balance  at 

first,  and  then  by  means  of  an  analyt- 

ical balance  to  find  the  exact  weight. 

According  to   (II)   we  have  now  the 

apparent  weight  n  of  the  flask  and  sub- 

stance in  the  air,  with  the  density  equal  j 

to  A.'.     After  obtaining,   according  to 

(IV),1  by  aid  of  m,  A.  and  X',  the  appa- 

rent mass  of  the  flask  m'  at  the  air  Fig-  8l- 

density  A',  then  we  have  as  the  apparent  mass  ?tl  of  the  sub- 

stance A  at  the  air  density  A/, 

nl  =  n  —  m   ] 

n^  is  reduced,  according  to  (III),  to  the  vacuum  weight  and 
we  obtain  then  as  the  real  mass  Ml   of  A, 


Then  the  second  component  B  of  the  solution  is  brought  into 
the  flask  and  care  is  taken  to  make  a  homogeneous  solution  by 
shaking.  Just  as  Ml  was  found,  we  find  now  the  true  mass 
M  of  the  solution  composed  of  A  and  B,  but  we  must  substi- 
tute now  in  (III)  in  making  the  reduction,  the  specific  gravity 
s  of  the  solution.  The  real  mass,  Mz,  of  the  component  B  is 


then 


M=M—  M,. 


We  proceed  in  the  same  manner  if  still  other  components  are 
to  be  added.  If  the  solution  contains  the  components  A  and  B 
only,  of  which  B  is  the  solvent,  then  the  percentage  strength, 
p,  of  active  substance  A  in  the  solution  is 

100  Ml 


(V) 


P  = 


M 


It  is  to  be  observed  that/,  also  the  per  cent,   of  the  solvent, 

1  The  density  of  the  glass  may  be  taken  as  2.5. 


PERCENTAGE   STRENGTH   OF   SOLUTIONS 

q  -.-  j  =  100  —  /,  are  quite  independent  of  the  tempera- 

ture ;  the  percentage  amount  p  gives  clearly  the  composition  of 
the  solution  ;  the  solution  is  completely  defined  through  p  only. 

It  is,  therefore,  advisable  in  following  changes  in  specific 
rotation  with  increasing  dilution  of  the  solution,  to  represent 
the  specific  rotation  as  a  function  of  p  or  q  as  is  done  on  page 
5,  rather  than  as  a  function  of  the  concentration.  If  wrater  is 
used  as  the  solvent,  it  should  be  thoroughly  boiled  so  as  to 
expel  all  the  air. 

In  this  manner,  when  necessary,  the  percentage  strength  p 
may  be  found  with  very  great  accuracy.  If,  for  example,  the 
normal  sugar  solution  so  commonly  used  in  saccharimetry,  in 
which  the  amount  of  sugar  is  about  23.7  per  cent.,  is  accu- 
rately prepared  by  weighing  and  is  then  filled  into  the  polari- 
zation tube,  in  which  operation  a  little  water  is  lost  by  evapo- 
ration, the  actual  percentage  strength  of  the  solution  in  the 
tube,  after  allowing  for  all  systematic  errors,  may  be  given  to 
within  Vjo.000  of. its  value;  that  is,  accurately  to  ±  2  or  3  units 
of  the  third  decimal  place.  But  if  the  weighings,  are  not  re- 
duced to  vacuo,  the  percentage  strength  would  be  too  large  by 
one  unit  in  the  second  decimal  place. 

167.  Change  in  the  Percentage  Strengthen  Filtration  of  the  Solution. 
—But  this  great  accuracy  in  the  percentage  strength  no  longer 
obtains  if,  on  account  of  turbidity,  one  is  obliged  to  filter  the 
solution,  because  then  by  partial  evaporation  of  the  solvent, 
the  percentage  amount  of  the  non-volatile  constituent  is  in- 
creased. In  order  to  obtain  an  estimate  of  the  extent  of  the 
error  so  caused  some  experiments  were  made,  and  partly  in 
this  way  that  the  whole  filtering  apparatus  was  placed  on  the 
balance,  and  partly  by  determining  the  strength  before  and 
after  filtration.  Plaited  filters  of  Swedish  paper  were  used 
and  the  funnels  and  vessels  were  kept  covered  as  well  as  pos- 
sible. 

Aqueous  solutions  :  a.  43.131  grams  of  water  filtered  in  four 
minutes  and  lost  0.019  gram  by  evaporation.  Air  tempera- 
ture, 18°.  99.614  grams  of  water  filtered  in  1 1  minutes  with  a 
loss  of  0.041  gram.  Temperature,  20°.  According  to  this, 
in  the  filtration  of  40  to  100  grams  of  a  10  per  cent,  solution, 


DETERMINATION    OF    SPECIFIC    GRAVITY  449 

the  percentage  strength  would  increase  by  0.004.  b.  In  the 
filtration  of  50  cc.  of  an  aqueous  solution  of  silver  nitrate, 
which  was  completed  in  three  minutes,  the  percentage  strength 
increased  from  9.708  to  9.713.  The  temperature  was  20°. 
The  increase  is  0.005,  which  agrees  with  the  first  determinations. 

Alcoholic  solutions  :  a.  31.007  grams  of  94  per  cent,  alcohol 
filtered  in  four  minutes  and  lost  0.067  gram  by  evaporation,  at  a 
temperature  of  18°.  71.494  grams  of  the  same  alcohol  filtered 
in  ten  minutes,  at  19°,  and  lost  0.114  gram.  If  the  above 
alcohols  had  contained  10  per  cent,  of  active  substance,  this 
amount  would  have  been  increased  in  the  first  filtration  to 
10.019  and  in  the  second  to  10.014  per  cent.  b.  50  cc.  of  a 
solution  of  silver  nitrate  in  78  per  cent,  alcohol  filtered  in  ten 
minutes,  at  23°,  and  increased  in  strength  from  9.686  to  9.714 
per  cent,  in  one  experiment,  and  to  9.736  per  cent,  in  another  ; 
that  is,  by  0.03  and  0.05. 

If  we  may  assume  that  the  evaporation  is  independent  of  the 
percentage  strength  and  proportional  to  the  amount  of  liquid 
filtered,  which  is  only  approximately  true,  it  may  be  estimated 
that  in  aqueous  solutions  after  filtration,  the  amount  is  in- 
creased by  about  0.005  for  each  10  per  cent,  of  substance,  and 
for  alcoholic  solutions  by  about  0.03  to  0.05. 

These  increases  in  percentage  strength  may,  therefore,  be 
quite  considerable  for  concentrated  solutions,  and  if  alcohol 
serves  as  the  inactive  solvent  the  first  decimal  place  even  may 
be  wrong  by  several  units.  Filtration,  therefore,  should  be 
avoided  as  far  as  possible. 

D.     DETERMINATION  OF  SPECIFIC  GRAVITY 

168.  Construction  and  Use  of  the  Pycnometer. — The  specific  grav- 
ity or  density  of  a  body  is  the  relation  of  its  mass  to  the  mass 
of  the  same  volume  of  water  at  4°.  The  choice  of  any  other 
temperature  is  inadmissible.  If  the  body  is  homogeneous  the 
specific  gravity  is  at  the  same  time  the  mass  of  the  unit  of 
volume,  the  gram  and  cubic  centimeter  being  naturally  used 
together. 

The  densities  of  solid  bodies  are  important  in  polarimetry 
only  so  far  as  employed  in  the  reduction  of  weights  to  vacuo, 
and  the  methods  of  determination  need  not  be  discussed  here. 
29 


450  DETERMINATION   OF   SPECIFIC   GRAVITY 

Reference  is  made  to  Kohlrausch's  "Praktische  Physik,"  1896, 
p.  57  to  60,  and  it  may  be  remarked  further  that  for  the  cases 
coming  into  consideration  here  the  floating  method  devised  by 
Retgers  gives  the  best  results. 

The  densities  of  liquids  may  be  found  by  aid  of  the  pycnom- 
eter,  the  Mohr  balance  or  the  aerometer.  But  the  last  two 
methods  require  larger  quantities  of  liquid  and  may  be  applied 
to  solutions  only  when  the  evaporation  of  the  sol  vent  is  slight; 
but  as  they  are  easily  subject  to  many  systematic  errors  and 
do  not  possess  at  all  the  accuracy  which  is  reached  without 
difficulty  with  the  pycuometer,  the  Mohr  balance  and  the 
aerometer  are  only  used  in  technical  work  for  approximate 
determinations,  while  for  scientific  investigations  the  pycnom- 
eter  alone  may  be  employed. 

With  the  pycnometer  the  mass  of  a  definite  volume  is  de- 
termined. Among  the  many  kinds  of  pycnometers  that  of 
Sprengel  gives  unquestionably  the  most  accurate  results.  The 
most  practical  form  is  shown  in  Fig.  82.  The  vessel  A  holds 
about  15  cc.  and  is  made  of  rather  thin  glass.  The  two  capil- 
lary tubes  B  and  C,  bent  in  the  middle,  are  fused  to  the  upper 
end  of  A.  The  extremities  of  these  are  ground.  The  inter- 
nal diameter  of  the  capillaries  is  not  the  same  ;  B,  which  has 
a  mark  at  D  is  about  0.9  mm,  while  C  is  smaller  and  about  0.4 
mm.  in  diameter.  In  order  to  be  able  to  hang  the  pycnometer 
on  the  balance  it  is  provided  with  a  platinum  loop  E,  as  shown 
in  the  figure.  To  prevent  evaporation  during  weighing,  and 
possible  loss  of  liquid  by  expansion  with  increase  of  tempera- 
ture, the  ends  B  and  C  may  be  closed  by  the  two  ground  glass 
caps  F  and  G.  To  distinguish  it  from  G  the  cap  F  is  marked 
by  a  blue  glass  bead  at  its  end  since  this  one  is  to  be  put  on 
the  capillary  marked  at  D.  To  facilitate  drawing  in  the 
liquid  the  bent  glass  tube  H  with  ground  end  may  be  attached 
to  the  wider  capillary  B,  and  to  the  narrow  capillary  C,  the 
bulb  J,  with  ground  neck,  to  which  a  bit  of  rubber  tubing  is 
attached.  The  definite  volume  of  the  pycnometer,  which  is 
always  used  filled,  reaches  from  the  point  of  C  to  the  mark  D 
and  changes  only  by  expansion  of  the  glass  with  the  tem- 
perature. 

The  pycnometer  is  cleaned  by  washing  with  distilled  water 


CONSTRUCTION   AND   USE   OF   THE   PYCNOMETER         451 


Fig.  82. 

and  alcohol,  the  latter  being  vaporized  finally  by  a  current  of 
air.  The  apparent  mass  of  the  empty  pycnometer  with  the 
two  glass  caps  F  and  G  in  the  air,  is  then  a  constant  to  within 
about  ±0.2  mg. ,  the  changes  on  account  of  variations  in  the 
density  of  the  air  taken  into  consideration.  In  the  determina- 
tions of  specific  gravity  it  is  not  necessary  to  make  allowance 
for  variable  air  density  as  may  be  seen  in  the  following  calcu- 
lation of  errors  for  the  specific  gravity  i .  i .  The  greatest  dev- 
iation in  the  density  of  the  atmosphere  from  its  mean  value 
of  0.00119,  or  0.0012,  is  about  ±0.00005.  As  the  water 
weight  of  the  pycnometer  is  not  commonly  redetermined  with 
every  new  specific  gravity  test  the  density  of  the  air  can  cause 
a  maximum  error  of  about  ±  9  units  in  the  fifth  decimal  place 
in  the  determination  of  liquid  densities  ;  but  it  is  assumed  here 
that  the  empty  pycnometer  is  reweighed  before  each  determi- 
nation, and  that,  therefore,  its  apparent  mass  in  the  air  can  be 
brought  into  the  calculation  with  an  error  of  at  most  ±  0.05 


452  DETERMINATION    OF   SPECIFIC    GRAVITY 

mg.  Leaving  out  of  consideration  rare  exceptional  cases,  the 
error  in  the  liquid  density  by  variations  in  the  air  density  is, 
as  a  rule,  less  than  4  units  in  the  fifth  decimal  place.  As  will  be 
further  seen  below,  all  other  uncertainties  taken  together  may 
produce  an  error  of  about  ±  2  units  in  the  fifth  decimal  place. 
By  adding  the  error  of  four  units  on  account  of  uncertain  air 
density  the  final  error  is  6  units,  that  is,  the  error  in  a  specific 
gravity  determination  is  ordinarily  only  ±  6  units  in  the  fifth 
place,  even  when  the  variable  air  density  is  left  out  of  considera- 
tion ;  this  degree  of  accuracy  in  specific  gravity  determinations 
is  sufficient  for  all  polarimetric  work.  It  is  likewise  unneces- 
sary, in  specific  gravity  tests,  to  make  double  weighings  in  de- 
termining the  apparent  masses  in  the  air  ;  if  the  weighing  is 
always  made  on  the  same  side  the  inequality  of  the  balance 
arms  is  completely  eliminated,  since  specific  gravity  is  the  re- 
lation of  two  masses  ;  it  is  assumed,  of  course,  that  the  rela- 
tion of  the  two  arms  is  sufficiently  constant,  which,  for  the 
small  loads  here  taken,  should  always  be  the  case  in  a  good 
balance. 

The  pycnometer  is  filled  with  distilled  water,  reboiled  to  free 
it  from  air,  and  brought  into  a  bath  of  constant  temperature. 
A  cylindrical  glass  dish  with  a  capacity  of  several  liters  may  be 
used  as  a  water-bath  ;  it  should  be  placed  in  a  round  wooden 
vessel,  the  bottom  of  which  is  lined  with  a  thick  layer  of  cotton, 
and  the  space  between  the  sides  of  the  glass  and  wooden  ves- 
sels should  be  also  packed  with  cotton.  For  temperatures  be- 
tween 15°  and  25°  the  temperature  of  the  water-bath  will  then 
remain  constant  to  within  a  few  hundredths  of  a  degree.  A 
standard  with  two  movable  arms  is  attached  to  the  wooden 
vessel.  One  supports  the  holder  K  (Fig.  82),  which  maybe 
made  of  a  bent  glass  rod  or  of  a  thick  piece  of  covered  copper 
wire,  while  the  other  supports  a  thermometer.  The  pycuo- 
meter  is  hung  in  the  holder  K,  and  is  immersed  in  the  water 
of  the  bath  to  the  level  of  the  mark  I).  The  thermometer, 
graduated  in  tenths,  the  accuracy  of  which  has  been  previously 
tested  (see  §161)  is  hung  as  close  as  possible  to  the  pycnometer 
and  care  is  taken  to  have  the  mercury  in  the  bulb  about  at  the 
level  of  the  middle  of  A.  If  the  water-bath  is  colder  than  the 
pycnometer,  the  liquid  in  the  latter  contracts  on  immersion  in 


CONSTRUCTION    AND   USE    OF   THE    PYCNOMETER         453 

the  bath,  but  only  in  the  wider  capillary  B,  while  the  nar- 
rower one  C  remains  always  full.  If  the  water  retreats  be- 
yond the  mark  D,  a  drop  of  water  on  a  glass  rod  is  held  to  the 
point  C.  This  is  immediately  drawn  into  the  narrow  capillary 
and  the  mass  of  water  moves  up  in  the  wider  tube  B.  Then 
the  outside  ends  of  B  and  C  are  carefully  cleaned  by  bits  of 
filter-paper.  After  about  ten  minutes,  the  pycnometer  and 
contents  will  have  come  exactly^to  the  bath  temperature,  which 
may  be  recognized  by  the  fact  that  the  liquid  meniscus  in  the 
capillary  B  remains  constant  in  position.  After  the  tempera- 
ture on  the  thermometer  is  read  as  accurately  as  possible,  C  is 
touched  with  a  bit  of  filter- paper  which  causes  the  meniscus 
in  B  to  move  toward  D  ;  at  the  moment  in  which  the  middle 
of  the  meniscus  just  reaches  D  the  filter-paper  is  withdrawn 
and  the  adjustment  is  completed  ;  in  the  adjustment  the  eye  is 
held  so  that  the  mark  D  appears  as  a  line.  Finally,  the  nar- 
row capillary  C  is  first  closed  with  the  cap  G  and  then  B 
with  the  cap  F.  When  this  is  done  the  pycnometer  is  taken 
from  the  bath  and  dried  with  a  soft  linen  cloth,  and  then  it  is 
placed  on  the  balance  where  its  apparent  mass  in  air  is  deter- 
mined. If  from  this  the  apparent  mass  of  the  empty  pycnom- 
eter be  subtracted,  the  difference  gives  the  apparent  mass  in 
air  of  the  water  which  fills  the  pycnometer  at  the  temperature 
of  the  bath.  This  apparent  mass,  which  depends  on  the  tem- 
perature only,  is  a  constant  for  the  pycnometer  used  and  need 
not  be  found  anew  for  each  specific  gravity  determination. 
After  some  practice  such  a  degree  of  accuracy  may  be  reached 
that  with  repeated  adjustment  and  reductions  to  the  same 
temperature,  the  apparent  water  masses  will  not  vary  by  more 
than  o.i  to  0.2  mg.  But  it  must  be  remembered  that  15 
grams  of  water  weighed  in  the  air  may  vary  about  ±  0.6  mg. 
in  maximum  by  reason  of  changes  in  the  air  density.  The 
above  calculation  of  errors  is  based  on  these  relations. 

After  cleaning  the  pycnometer  with  alcohol  and  drying  it,  it 
is  filled  with  the  liquid  whose  specific  gravity  is  to  be  found. 
All  manipulations  are  now  the  same  as  before  with  water. 
The  adjustment  and  weighings  are  made  at  least  twice  to 
avoid  possible  errors.  By  subtracting  the  apparent  mass  of 
the  empty  pycnometer  from  that  of  the  filled,  the  apparent 


454  DETERMINATION   OF   SPECIFIC    GRAVITY 

mass  of  the  liquid  in  the  air  is  obtained.  By  repeated  weigh- 
ings, and  reductions  to  the  same  temperature,  this  should  vary 
at  most  by  o.  i  to  0.2  mg. 

169.  Calculation  of  the  Specific  Gravity.  —  The  following  is  the 
calculation  of  the  specific  gravity.     We  represent  by 

Wot  the  apparent  mass  of  the  water  in  the  air  at  the  tem- 

perature /0  ; 
F,     the  apparent  mass  of  the  liquid  in  the  air  at  the  tem- 

perature /  ; 

<20,    the  specific  gravity  of  the  water  at  the  temperature  /0  ; 
3/3,  =  0.000024,  the  coefficient  of  cubical  expansion  of 

glass  ; 

A.,       =0.0012,  the  air  density; 

dt}     the  density  of  the  liquid  at  the  temperature  /,  referred 
to  water  at  4°. 
Then 

\ 

~ 


In  this,  the  first  factor  is  the  rough  uncorrected  specific  gravity, 
the  second  and  third  factors  are  corrections.  The  second 
factor  corrects  the  specific  gravity  on  account  of  tempera- 
ture changes,  and  the  third  comes  from  the  reduction  of  the 
weights  to  vacuo.  As  already  explained  in  the  last  paragraph, 
we  obtain  the  specific  gravity  with  the  pycnometer  to  within 
about  ±  6  units  in  the  fifth  decimal  place.  The  specific 
gravity  may  be  given,  therefore,  to  the  fifth  decimal,  but  the 
first  factor  must  be  calculated  with  seven-place  logarithms. 
If,  in  each  weighing,  the  air  density,  A,  is  found  according 
to  equation  (I)  (§165),  then 

F'  O       F'O 
(II)  d,--    ^  +  ^  3ft  ((,-/), 

in  which  W£  and  P  are  the  true  masses  of  the  water  and  the 
liquid,  reduced  to  vacuo,  by  aid  of  equations  (I)  and  (III) 
(§165). 

The  values  of  the  specific  gravity,  Q0,  of  water  at  different 
temperatures  of  the  hydrogen  thermometer  are  found  from  the 
following  table,  which  contains  the  mean  values  of  Thiesen, 
Scheel  and  Marek.  The  numbers  are  accurate  to  about  five 


CALCULATION   OF   THE    SPECIFIC   GRAVITY 


455 


units  in  the  sixth  decimal  place,  as  may  be  seen  by  com- 
parison with  the  latest  observations.1  A  fuller  table  is  found 
in  L,andolt  and  Boernstein's  Tables,  1894,  p.  37. 


/„. 

A. 

4>. 

0» 

4> 

0+ 

0° 

0-999  874 

18.0° 

0.998  628 

21.0°     0.998023 

I 

930 

i 

609      i         ooi 

2 

970 

2 

590 

2 

0.997  979 

3 

993 

3 

57i 

3 

957 

4 

I.OOO  OOO 

4 

552 

4 

935 

5 

0.999  992 

5 

533 

5 

913 

6 

969 

6 

5H 

6 

890 

7 

931 

7 

495 

7 

868 

8 

878 

8 

476 

8 

846 

9 

812 

9 

456 

9 

823 

JO 

731 

19.0 

437 

22.0 

800 

ii         637 

i 

417 

I 

778 

12             530 

2 

397 

2 

755 

13             410 

3 

377 

3 

732 

14 

277 

4 

357 

4 

709 

15 

132 

5 

337 

5 

685 

16 

0.998  976 

6 

317 

6 

662 

7 

296 

7 

639 

17.0      808 

8 

276 

8 

615 

i        790      9 

255 

9 

592 

2           772 

3        755 

20.0 

235 

23 

568 

4        737 

I 

214 

24 

326 

2 

193 

5        719      3 

172 

25 

073 

6        701      4 

151 

26 

0.996  811 

7        683 

27 

540 

8        664 

5 

130 

28 

260 

9        646 

6 

109 

29 

0.995  971 

7 

087 

Q 

066 

30 

674 

9 

044 

3i 

368 

If,  in  the  equations  (I)   and  (II),  (/0  —  i)  amounts  to  but  a 

1  Thiesen,  Scheel,  and  Diesselhorst  :  Wied.   Ann.,  60,  340  (1897)  ;  'Die  Thatigkjeit 
der  Physikalisch-Technischen  Reichsanstalt,"  Ztschr.  fur  Instrum.,  17,  (1897). 


456  DETERMINATION   OF   SPECIFIC    GRAVITY 

few  degrees,  it  is  sufficient  to  take  for  3  ft  the  mean  value 
0.000024.  But  it  is  always  better  to  find  the  coefficient  of  ex- 
pansion, 3/J,  of  the  glass  of  the  pycnometer  by  direct  experi- 
ment. For  this  purpose,  the  pycnometer  is  weighed,  filled 
with  air-free  water  at  two  different  temperatures.  If,  for  ex- 
ample, several  determinations  are  made  at  about  10°  and  30°, 
3/S  may  be  found  accurately  within  about  2  per  cent.  If  the 
two  temperatures  are  /,  and  tv  writh  /2  >  /,,  Q}  and  Q.,  the  cor- 
responding specific  gravities  of  water,  W^  and  W^  the  masses 
of  the  water  contained  in  the  pycnometer  at  temperatures  /t 
and  /.,,  then 

" 


W,  0,  (',->,) 

Although  the  numerator  may  be  simplified  to  ^l\Ql  —  W\  Oi 
it  is  still  more  convenient  in  working  with  definite  numbers  to 
use  the  above  form  of  the  equation.  If  the  density  of  the  air 
remains  constant  throughout  the  experiment,  it  is  not  neces- 
sary to  reduce  the  weights  to  vacuo,  as  3  ft  is  dependent  only 
on  the  ratio  W^  :  W,. 

170.  Variations  in  Specific  Gravity  with  the  Temperature.— 
In  all  more  accurate  polarimetric  work,  as  shown  in  §  162, 
changes  of  specific  gravity  with  the  temperature  must  be 
known  and,  therefore,  the  coefficient  of  cubical  expansion  of 
the  solution  must  be  found.  This  is  best  done  by  aid  of  the 
pycnometer.  Let  this  contain  the  mass  of  liquid  Fl  at  the  tem- 
perature /,,  and  at  the  higher  temperature  f.2  the  mass  F.r  If 
3  ft  is  the  coefficient  of  cubical  expansion  of  the  glass,  then  the 
mean  coefficient  of  expansion  of  the  liquid,  y,  between  /j  and  /.,, 
or  also  (with  sufficient  accuracy)  the  true  coefficient  for  the 

temperature  -L—  —  -  ,  is  given  in  form  suitable  for  calculation 
by 


y  ,,+,.== 


*i  l\ 


As  y  is  dependent  on  the  ratio  /•*  :  F.,  only,  it  is  not  necessary, 
constant  air  density  assumed,  to  reduce  the  weighings  to  vacuo. 
If  the  temperature  difference,  /2  —  /,,  is  taken  as  about  15°,  the 
coefficient  of  expansion  may  be  easily  determined  to  within 
about  3  per  cent.,  which  is  sufficient  for  all  polarimetric  work. 


VARIATIONS    IN   SPECIFIC    GRAVITY  457 

As  far  as  the  variation  in  y  with  the  temperature  is  con- 
cerned, we  may  assume  this  relation  with  sufficient  accuracy 
for  simple  liquids  as  well  as  for  solutions  of  definite  percentage 
strength, 

(V)  yt  =  y^  +  a(t-2o}, 

in  which  a  is  a  constant  peculiar  to  the  liquid.  If,  therefore, 
we  find  y  for  two  different  temperatures,  then  we  may  calcu- 
late first  the  two  constants  /20,  and  a,  and  next  the  coefficient 
of  expansion  for  any  desired  temperature  ;  it  is  required,  there- 
fore, to  find  the  mass  of  the  liquid  in  the  pycnometer  for  at 
least  three  different  temperatures. 

For  solutions,  y  varies  also  with  the  percentage  strength  p 
of  dissolved  substance,  so  that  y  must  be  written  as  a  function 
of  p  and  /  in  the  form 

(VI)  y  =  f  +  gp  +  h(t—  20)  +  ip(t  -  20), 

in  which  y,  g,  h,  and  i  are  four  constants.  If  then  the  equation 
(V)  is  established  first  for  the  pure  solvent,  and  then  for  a  sin- 
gle solution  of  percentage  strength  p,  the  four  constants  may  be 
found  in  a  manner  easily  seen,  and  y  may  then  be  calculated 
for  any  desired/  and  /.  In  case  the  equation  (V)  has  been 
found  for  several  solutions  of  different  strengths,  p,  the  four 
constants  may  be  calculated  by  aid  of  the  method  of  least 
squares. l 

As  an  example,  we  may  take  the  expansion  of  a  pure  sugar 
solution  in  water.  According  to  Schonrock2  the  dilation 
coefficient,  y,  between  11°  and  26°,  of  a  sugar  solution  with 
percentage  strength  between  p  =  o  and  p  =  30,  is  given  by 
the  equation 

y  =  0.000208  --{-  0.0000037^  -f  0.0000108  (/  —  20) 
—  0.000000 1 9  p(t  —  20). 

This  formula  gives  the  true  coefficient  of  expansion  accu- 
rately to  within  ±  0.000008. 

If  the  equation  (VI)  is  found  for  y,  and  the  specific  gravity 
d  at  the  definite  temperature  /'  has  been  determined,  the 
specific  gravity  for  any  other  temperature  /  may  be  found  from 
the  equation 

(VII)  dt  =  d,  +  d,  Yi±L  (/'  ~  t). 

2 

1  See  Kohlrausch  :  "Praktische  Physik,"  1896,  p.  9. 
-  Schonrock  :  Ztschr.  fiir  lustrum.,  16,  243  (1896). 


E.  DETERMINATION  OF  THE  CONCENTRATION  OF  SOLUTIONS 
171.  Calculation  of  the  Concentration  from  the  Specific  Gravity  and 
Percentage  Strength. — The  concentration  c,  by  which  is  under- 
stood the  number  of  grams  of  active  substance  in  100  cc.  of 
solution,  is  found  by  taking  the  product  of  the  percentage 
strength  p,  and  the  specific  gravity  dtt  found  as  explained 
above : 

(I)  ct=pdt. 

While,  now,  the  percentage  strength  p  is  perfectly  indepen- 
dent of  the  temperature,  the  concentration  c  varies  with  it. 
We  have,  in  analogy  with  equation  (VII)  (§170), 

(II)  ct=  Ce+CtYt+At  —  t). 

2 

Asp  and d  may  be  determined  with  great  accuracy,  it  fol- 
lows from  (I)  that  c  may  be  also  exactly  found.  As  we  have 
seen  in  §166,  it  is  possible,  for  example,  to  determine  the  per- 
centage strength  of  a  24  per  cent,  sugar  solution  to  about 
±  three  units  in  the  third  decimal  place.  As,  further,  accord- 
ing to  §i 68,  its  specific  gravity  may  be  found  accurately  to 
about  ±_  six  units  in  the  fifth  decimal  place,  it  follows  that  the 
concentration  (about  26)  may  be  found  for  the  same  temper- 
ature to  within  about  Veooo  °f  *ts  amount;  that  is,  to  ±  4  units  in 
the  third  decimal  place  accurately. 

But  equation  (/)  gives  the  exact  concentration  only  when  the 
specific  gravity  d  is  referred  to  water  at  4°.  Of  course,  in  this 
case,  we  understand  by  i  cc.  the  volume  which  i  gram  of  water 
occupies  at  4°  weighed  in  vacua.  This  cubic  centimeter,  almost 
universally  employed  in  scientific  work,  is  usually  designated 
as  the  true  cubic  centimeter,1  and  is  always  understood  in  what 
follows,  unless  something  else  is  mentioned.  This  true  or  prac- 
tical cubic  centimeter  is,  of  course,  to  be  distinguished  from 
the  theoretical  cubic  centimeter;  that  is,  the  volume  of  a  cube 
whose  edge  is  i  cm.  long.  From  the  investigations  of  Men- 
deleeff  and  Mace  de  Lepinay,  it  follows  that  100  practical 
cubic  centimeters  =  100.010  theoretical  cubic  centimeters.  If, 
for  example,  100  practical  cubic  centimeters  contain  26  grams 

1  A»  distinguished  from  the  Mohr  cubic  centimeter. 


PREPARATION  OF  SOLUTIONS  IN  MEASURING  FLASKS     459 


of  substance,  then,  with  reference  to  theoretical  cubic  centi- 
meters, c  =  25.9974  ;  in  scientific  work  calculations  are  never 
based  on  theoretical  cubic  centimeters. 

Concerning  the  Mohr  cubic  centimeter,  no  longer  used  in 
science,  see  §126. 

172.  Preparation  of  Solutions  in  Measuring  Flasks. — The  concen- 
tration may  also  be  found  directly  by  dissolving  a  weighed 
amount1  of  the  active  substance  in  a  measuring  flask  of  definite 
volume.  But  this  method  has  the  disadvantage  that  the  deter- 
mination of  volume  in  the  measuring  flask  is  by  no  means  as 
accurate  as  in  the  pycnometer,  and  further,  that  larger  vol- 
umes of  liquid  must  be  brought  to  a  constant  temperature, 
which  requires  a  correspondingly  longer  time.  For  exact 
experiments  the  method  with  the  pycnometer  is  decidedly  pref- 
erable. 

The  measuring  flasks  to  be  used  are  illustrated  in  Fig.  83, 
and  have  a  volume  of  20  to  200  cc. , 
with  a  neck  about  10  mm.  wide  ;  the 
circular  mark  on  the  neck  should  be 
down  near  the  body  so  as  to  dimin- 
ish inequality  in  the  solution  as  far 
as  possible.  Measuring  flasks  with 
a  long  narrow  neck  divided  into 
tenths  of  cubic  centimeters,  and 
closed  with  ground  glass  stoppers, 
and  which  have  still  sufficient  mix- 
ing space  above  the  upper  mark  so 
that  solutions  with  any  volume  be- 
tween loo  cc.  and  no  cc.  may  be 
made,  are  very  practical.  Before 
the  solution,  made  either  in  the  flask 
itself  or  in  another  vessel,  is  diluted 
to  the  mark,  a  thermometer  is  dipped  in  it  and  the  normal  tem- 
perature (20°)  secured  by  help  of  a  water-bath.  Finally,  the 
thermometer  is  lifted,  rinsed  off  with  a  little  of  the  solvent, 
more  is  filled  in  to  the  mark  and  the  whole  is  well  shaken  after 
inserting  the  glass  stopper. 

The  contents  of  the  measuring  flask  must  be  accurately  de- 

1  The  weight  must,  of  course,  be  reduced  to  vacuo. 


460  CONCENTRATION   OF   SOLUTIONS 

termined  by  weighing  before  use.  For  this  purpose,  it  is  filled 
nearly  to  the  mark  with  air-free  water,  a  thermometer  is  in- 
serted and  by  warming  or  cooling  in  a  water-bath  it  is  brought 
to  the  normal  temperature  /,  for  which  it  is  to  be  used.  After 
withdrawing  the  thermometer,  enough  water  is  added  to  bring 
the  lower  edge  of  the  concave  liquid  surface  exactly  tangent  to 
the  mark  when  viewed  horizontally.  Then,  all  drops  hanging  in 
the  neck  of  the  flask  are  removed  and  the  mass  P  of  the  water, 
in  vacuo,  found  according  to  §165  and  §166.  If  the  specific 
gravity  of  water  at  the  temperature  t  of  experiment  is  Q  (see 
table,  §169),  then  the  volume  Vt  in  cubic  centimeters,  which 
the  flask  contains  at  t°,  is  given  by  the  equation  : 


It  is  possible  in  this  manner,   with  several  weighings,   to  find 
the  volume  of  the  flask  within  about  ±  0.03  cc. 

When  a  measuring  flask  is  to  be  used  at  any  other  tempera- 
ture /'  than  the  temperature  t  for  which  it  was  graduated,  the 
cubical  expansion  of  the  glass  must  be  taken  into  consideration. 
If  3  ft  represents  this  coefficient  (in  the  mean  0.000024),  and 
Vt  the  volume  of  the  flask  at  the  temperature  of  graduation, 
then  this  formula  may  be  used  in  finding  the  volume  at  /'  : 
(IV)  Vt,--~-  Vt  +  V(Zft(t'-t). 

To  obtain  an  idea  of  the  errors  connected  with  the  determi- 
nation of  concentration  of  solutions  made  in  a  measuring  flask, 
we  can  take  as  an  illustration  the  preparation  of  the  normal 
sugar  solution  commonly  employed  in  saccharimetry.  Since  at 
17.5°,  26.003  grams  of  sugar  (true  mass)  must  be  dissolved  to 
make  100  cc.  (§126),  the  concentration  of  a  correct  normal 
solution  is  f,7.s  =  26.003.  If  we  now  assume  that  the  sugar 
is  correctly  weighed  out  and  that  errors  in  the  flask  in  con- 
junction with  inaccuracies  in  filling  to  the  mark  amount  to 
only  ±1  0.02  cc.,  the  concentration  is  already  wrong  by 
=F  0.0052,  an  error  which  is  larger  than  that  found  in  §171. 
On  the  other  hand,  assuming  that  at  the  time  of  preparing  the 
solution  the  water  has  a  temperature  of  18.5°  instead  of  17.5°, 
according  to  (IV)  the  volume  of  the  measuring  flask  is  no 
longer  icocc.,  but  100.0024,  and  the  26.003  grams  of  sugar  are 
contained  in  this.  Accordingly  the  concentration  of  the  pre- 


CALCULATION   OF    ERRORS  461 

pared  solution  is  clB..  =  26.0024  ;  as  further,  the  coefficient  of 
expansion  of  a  normal  sugar  solution  at  18°  is  0.000283,  then, 
according  to  (II),  r17.3  =  26.0098.  In  this  case,  therefore,  a 
temperature  difference  of  i  °  in  the  preparation  of  the  solution 
makes  a  difference  of  0.007  in  the  concentration.1  //  is  seen 
from  this  how  closely  the  temperature  must  be  controlled  when 
solutions  are  prepared  in  the  measuring  flask. 

F.     EFFECT  OF  THE  DIFFERENT  ERRORS  OF  OBSERVATION 
ON  THE  SPECIFIC  ROTATION 

173.  Calculation  of  Errors.  —  Each  of  the  factors  entering   the 

i  oo  or         100  at    . 
formulas  \ci\  -=  or  —  -  —  ,  is  attended  by  a  certain  error 

of  observation.  If  we  represent  by  /(«)  the  error  in  or,  by 
f(a)  the  error  in  [or]  caused  by  /(a),  and  if/(  /),/(/).  .  -F(l), 
F(6}  have  the  same  meanings  with  reference  to/,  /,  then,  since 
[a]  is  proportional  to  aj  /,...,  the  following  simple  relations 
exist  : 


, 

In  the  calculation  of  the  errors,  /%  it  is  only  necessary  to 
use  approximate  values  and  two  places  of  figures  will  be  suffi- 
cient. 

To  secure  a  fairly  close  idea  of  the  influence  which  each 
error  has  on  the  value  of  [a]  ,  we  shall  carry  through  the  com- 
putation for  the  case  of  the  determination  of  the  specific  rota- 
tion of  cane-sugar  in  water  where  [a]  is  about  66.  Let 
a  =  35°,  /  =  2  dm.,  p  =  24,  d  ==  i.i  ;  these  factors  may  be 
found  with  about  this  degree  of  accuracy  :/(«)  =  dz  0.004°, 
/(/)  i=  d=  0.0002  dm.,  f(p}  =  ±  o.oo3,/(y)  =  dz  0.00006. 
From  these  the  following  errors  are  calculated  for  \_ot~]  \  F(a) 
±  0.008,  F(l}  ==  q=  0.007,  F(p)  =  =p  0.008,  F(d)  =  =F 
0.004.  As  seen,  the  errors  in  [ar]  are  of  the  same  order,  so 
that  the  final  accuracy  in  [«]  is  about  ±  0.014,  or  0.02  per 
cent.  ;  that  is,  the  specific  rotation  in  this  case  is  found  to  within 
about  Vsooo  °f  ^s  value.  In  all  investigations  one  must  take 

1  Corresponding  to  0.03    Yentzke. 


462  CALCULATION   OF   ERRORS 

into  account,  in  this  manner,  the  degree  of  accuracy  with  which 
the  different  measurements  may  be  carried  out,  in  order  that  an 
estimate  of  the  value  of  the  final  result  is  possible. 

The  chemist  may  reply  that  such  great  accuracy  in  the 
specific  rotation  is  not  to  be  reached  because  of  the  chemical 
impurity  of  the  substance  investigated.  While  this  is  actually 
true  in  very  many  cases,  this  very  fact  should  call  for  more  accu- 
rate work  in  the  determination  of  specific  rotation.  //  is  only 
after  preparations,  which  have  been  made  or  purified  by  different 
methods,  have  in  turn  been  examined  with  great  accuracy,  with 
the  result  that  differences  in  the  specific  rotation  arc  found  which 
lie  quite  outside  the  errors  of  observation,  that  it  may  be  stated 
with  positiveness  that  these  differences  are  due  to  impurities  in  the 
material  investigated.  At  the  present  time,  in  the  great 
majority  of  cases,  and  especially  in  respect  to  the  commonest 
and  most  frequently  studied  bodies,1  we  are  still  quite  uncertain 
whether  the  different  values  in  the  specific  rotation,  found  by 
different  observers,  are  due  to  errors  of  observation  or  to  im- 
purities in  the  substances.  Along  with  accidental  errors, 
which  follow  from  uncertainties  in  the  observations,  there  are 
the  systematic  errors  which  are  due  in  the  main  to  the  pecu- 
liarities in  individual  instruments,  and  to  these  the  greatest 
attention  must  be  paid.  Considering  the  delicacy  of  instru- 
ments and  methods  to-day,  certainly  no  great  skill  is  required 
to  obtain  results  which  agree  perfectly  with  each  other  after 
repeating  whole  series  of  observations  by  one  and  the  same 
method  ;  but  the  skill  of  the  observer  is  to  be  judged  rather  by  his 
success  in  eliminating  systematic  errors  by  variations  in  methods 
and  accurate  investigation  of  the  apparatus  employed.  Bessel's 
statement  cannot  be  too  highly  appreciated,  that  every  piece 
of  apparatus  must  be  twice  constructed,  first  by  the  instru- 
ment-maker, then  by  the  observer  ;  which  is  to  say,  that  be- 
fore use  every  measuring  instrument  must  be  accurately  investi- 
gated as  to  its  errors. 

For  fuller  details  concerning  calculation  of  errors,  see  Kohl- 
rausch's  "Praktische  Physik,"  1896,  p.  i  to  27,  or  Ostwald's 
"Physiko-chemische  Messungen,"  1893,  p.  i  to  18  (consider 
especially  page  9). 

1  See,  for  example,  the  constants  of  rotation  of  cane-sugar,  tartaric  acid,  alkaloids, 
etc.,  given  in  Part  VI. 


PART  FIFTH 

Practical  Applications  of  Optical  Rotation 


i.  Determination  of  Cane-Sugar.     Saccharimetry 

A.  Determination  of  Sugar  with  Instruments  having  a  Circular 

Graduation 

174.  By  aid  of  the  polaristrobometers  described  in   §98  to 
§121,  the  concentration  c  or  the  number  of  grams  of  sugar  in  a 
solution,  may  be  found  by  the  following  formula,   where  we 
measure  the  angle  of  rotation   aD  for  a  layer  /  decimeters  in 
length  : 

100  Of 

=  7T^r 

As  shown  by  Table  II  on  page  465,  to  follow,  we  can  take  for 
the  specific  rotation  of  cane-sugar  the  constant  value  [«]  D  =-  + 
66.5,  for  all  concentrations  below  c  =  30.  This  is  sufficiently 
close  for  practical  work,  as  c  may  be  found  from  it  with  accu- 
racy to  o.oi  or  0.02.  If  this  number  is  substituted  in  the  above 
equation,  there  follows, 

c~  1.504  -j-. 

For  a  2  dm,  tube 

C=  0.752  aD. 

The  percentage  amount  of  pure  sugar  in  a  solid  saccharine 
body,  of  which  P  grams  have  been  dissolved  to  make  100  cc., 
and  which  is  examined  in  an  instrument  with  circular  gradu- 
ation, is  given  by  the  proportion, 

P ' :  0.752  a  :  :  100  \x  ; 

75-2  «/, 
~~P~ 

175.  If  we  have  to  analyze  very  strong  sugar  solutions,  or  if 
the  greatest  degree  of  accuracy  is  desired,   then  the  change  in 


464       PRACTICAL   APPLICATIONS   OF   OPTICAL   ROTATION 

the  specific  rotation  \_ae~]  with  the  concentration  must  be  taken 
into  consideration.  The  following  formulas  are  given  to  show 
the  dependence  of  the  specific  rotation  of  cane-sugar  on  the 
percentage  strength  /  : 

I.  [«]£  =66.386+  0.015035 /»  —  o.ooo39S6/>-(  Tollens.)1 
II.  [#] £  =  66.438  -  o.oio3i2/>  —  o. 0003545 />2(Nasini  and  Villavecchia)1 
The  following  table  (Table  I)  contains  in  columns  d  and  e 
the  specific  rotations  calculated  according  to  the  above  formulas, 
and  corresponding  to  percentage  amounts  of  sugar  (column  a), 
increasing  from  5  to  5  per  cent : 

TABLE  I 


a.                    b. 

c. 

d. 

e. 

f. 

-    Per 

Sp.gr.  rf--4 
Interpolated 

Con- 
centration 

Specific  rotation    [tf]  £. 

cent 

from  the             (c=fi.d 

amount. 

nearest 
values  of 
Tollens. 

according  to 
Tollens). 

Calculated  by 
Formula  I 
(Tollens).  re- 
ferred to 

Calculated  by 
Formula  II 
(Nasini),  re- 
ferred to 

Calculated  by 
Formula  III.- 
referred  to 

P- 

d. 

c. 

P- 

P- 

c. 

5 

I.OI786 

5-0893 

66.451 

66.480 

66.473 

10 

1.03819              10.3819               66.496 

66.506 

66.500 

15 

1.05926              15.8889               66.522 

66.513 

66.514 

20 

.08109              2I.62I8                66.527 

66.502 

66.513 

25 

.10375              27.5938               66.513 

66.474 

66.496 

30 

.12721              33-8163                66.479 

66.428 

66.460 

35 

•15*53           40.3036            66.424 

66.365 

66.404 

40 

.17676           47-0704            66.350 

66.283 

66.324 

45 

.20288           54.1296            66.256 

66.184 

66.217 

50 

.22995 

61.4975 

66.142 

66.067 

66.081 

The  values  in  columns  d  and  e  may  be  used  when  the  per- 
centage amount  of  sugar,  p,  in  100  parts  by  weight  of  a  solu- 
tion is  to  be  found,  but  the  specific  gravity  must  also  be 
known.  We  find  p  from 

looar 

=  Id  \a\  ' 

We  proceed  in  this  way.  An  approximate  value  for  \_a\  is 
substituted  and/>  calculated  ;  then  the  exact  value  of  [«]  is 

1  See  Part  VI,  Constants  of  Rotation. 
'-'  See  next  page. 


SACCHARIMETRY 


465 


taken  from  the  table  or  is  interpolated,  and  on  substitution  of 
this  in  the  formula  the  exact  value  of  p  may  be  found. 

But  the  case  is  much  more  common  in  which  we  desire  to 
find,  not  the  percentage  amount,  but  the  concentration  of  a 
solution.  The  formula  given  above, 

100  Of 

c  =-•      r   .. , 

possesses  this  advantage  that  the  specific  gravity  of  the  sugar 
solution  investigated  need  not  be  known,  and  that  at  the  same 
time  the  latter  may  contain  inactive  substances  also  along  with 
the  sugar.  As  up  to  the  present  time  we  have  had  no  formula 
which  presented  the  specific  rotation  of  cane-sugar  as  depend- 
ent on  the  concentration,  the  following  new  one  has  been  cal- 
culated from  the  observations  of  Tollens  and  Nasini : 
III.  [**]/?  =  66.435  —  0.00870  r—  o.ooo  235  c-  (holds  for  r— -o  to  65). 

The  values  of  [<*] ,  according  to  this  formula,  are  given  in 
column  f  of  the  above  table  opposite  the  corresponding  values 
from  Formulas  I  and  II. 

It  will  be  recognized  that  all  the  values  from  Formula  III 
lie  within  those  from  the  formulas  of  Tollens  and  Nasini.  As 
the  latter  differ  from  each  other  only  by  amounts  which  cor- 
respond to  the  unavoidable  errors  of  observation,  Formula 
III,  for  the  concentration,  possesses  a  degree  of  accuracy  which 
satisfies  all  practical  requirements. 

The  specific  rotation  of  sugar  solutions  with  from  i  to  65 
grams  of  sugar  in  100  cc.  is  then  given  by  the  following  : 

TABUS  II. 


c. 

Mi 

Diff.  for 

c  =  i. 

C. 

MS- 

Diff.  for 

c  =  i. 

I 
5 

10 

15 

20 
25 
30 

66.443 
66.473 

66-499 
66.513 
66.515 
66.506 
66.485 

0.0075 
—  0.0052 
0.0028 
-f  0.0004 
0.0018 
—  0.0042 
--  0.0066 

35 
40 

45 
50 

55 
60 

65 

+  66.452 

66.407 

66.351 
66.283 
66.203 

66.ni 
66.007 

—  0.0090 
—  O.OII2 
—  0.0136 

—  0.0160 
—  0.0184 
—  0.0208 

The  following  example  shows  that  the  change  in  the  specific 
rotation  is  marked  enough  to  appreciably  affect  the  results  of 
optical  analysis  with  solutions  of  considerable  concentration. 

30 


466       PRACTICAL   APPLICATIONS   OF   OPTICAL    ROTATION 

Let  a  rotation  of  83. 1 1°  be  found  with  a  2  dm.  tube.  Accord- 
ingly, the  concentration  would  be  0.752  X  83. 1 1  =  62.5  grams 
of  sugar  in  100  cc.  But,  according  to  the  table,  the  specific 
rotation  of  sugar  for  this  concentration  is  66.06.  The  true 
concentration  will  then  be  found  from  the  equation  : 

loo  X  83.11 
C  -      2  X  66.06      "  62'9'  gramS" 

B.  Determination  of  Cane-Sugar  with  Application  of  Wedge- 
Compensation  Instruments  and  the  Ventzke  Scale. 
176.  These  instruments  which  have  been  described  in  detail 
in  §122  to  §137  are  the  only  ones  practically  employed  in  the 
sugar  industry.  In  the  course  of  time  many  different  directions 
have  been  given  for  the  manner  of  using  them,  as  well  as  for 
the  preparation  of  solutions  of  different  saccharine  substances, 
but  at  the  same  time  experience  has  shown  that  in  the  results 
of  different  observers  differences  are  often  found,  the  cause  of 
which  must  lie  in  the  lack  of  uniformity  in  methods  of  pro- 
cedure. In  consequence  of  this,  it  has  become  necessary  from 
the  side  of  the  sugar  chemist,  as  well  as  from  that  of  revenue 
administration  to  establish  definite  methods,  and  this  has  been 
recently  done  by  the  Rules  of  Procedure  provided  by  the 
German  Sugar  Tax  Law  of  May  27,  1896,  appendices  A,  B,  C, 
and  E.  The  provisions  in  the  last  are  based  in  part  on  many  in- 
vestigations carried  out  in  the  laboratory  of  the  Society  for 
Promotion  of  the  German  Beet-Sugar  Industry,  and  particu- 
larly those  of  Herzfeld,1  and  partly  on  decisions  reached  in  the 
meetings  of  societies  of  commercial  chemists.2 

1  See  especially  the  following  :  Herzfeld  :  Ztschr.  Riihenzucker-Ind.,  40,  167  to  214 
(1890),  "Die  Bestimmung  des  Zuckergehaltes  der  Handelswaare  ;"  41,  685  (1891),  "Best, 
des  Invertzuckers  in  Melassen  ;"  43,14710  259(1892),  "Ueberdie  zweckmassigste  Art 
der  Werthschatzung  des  Rohzuckers  ;"  43,  (1893),  "Die  Wasserbestimmung  ira   Roh- 
zucker."     Also,  Hammerschmidt  :  Ztschr.  Riibenzucker-Ind.,  40,  465  (1890),  "Verall- 
gemeinerung  der  Clerget'schen  Methode."  41,  157  (1891),  "Bestimmung  der  Saccharose 
mittelst  der  Inversionsmethode."    Besides  these,  many  other  papers. 

2  See  Ztschr.  Riibenzucker-Ind.,  36,  6  (1886),  "Bericht  iiberdie  Sitzung  der  Invert  - 
zucker-Commission  in  Magdeburg  vom  5  Dec.,  1885,"  and  page  11  appendix  to  this  ;  40, 
439  (1890),  "Rundschreiben  vom  6  Juli,  1890,  an  die  Handelschemiker,  betr.  die  Bestim- 
mung der  Ram  nose  und  des  Invertzuckers;"  page  443,  "Anleitung  zur  Bestimmtmg 
des  Gehaltes  an  Ramnose  und  Invertzucker  in  den  Producten  der  deutschen   Ruben 
zuckerfabrikation  ;  "  page  446,   "Arbeitsvorschrift  fur  die  Invertzuckerbestimmung  ;  " 
4S.73(i895).  Allg.  Theil,  "Bericht  iiber  die  Versammlung  der  Handelschemiker  vom 
12  Marz,   1895,  in  Berlin;  "46,  180   (1896),  Allg.   Theil,   "Sit/.ung  (k-r  Commission  der 
Handelschemiker   behufs    Priifung   von    Normalquarzplatten    xur  Controle  der  Sac. 
charimeter. " 


SACCHARIMETRY  467 

177.  For  the  work  in  hand,  it  appears  most  practical  to  give 
below  an  exact  reprint  of  the  four  appendices  of  the  sugar  tax 
law  referred  to  (in  the  order,  C,  A,  B,  and  E).1 

[Note  by  Translator. — Although  the  directions  given  below 
apply  in  some  cases  to  German  conditions  only,  it  was  thought 
best  to  allow  them  to  stand  as  written,  inasmuch  as  they  are 
suggestive  and  have  been  pretty  generally  followed  in  the  prac- 
tice of  other  countries.  Permission  was  given  by  the  author 
to  modify  this  section  at  the  discretion  of  the  translator,  but 
instead  of  doing  this,  attention  will  be  called  to  the  following 
books  and  pamphlets  where  other  details  may  be  obtained  : 

Wiley's  "  Agricultural  Analysis."  Vol.  III.      Parts  2  and  3. 

Allen's  "Commercial  Organic  Analysis."  Vol.  I,  3rd  ed. 
p.  243-379. 

1 '  Methods  of  Analysis  adopted  by  the  Association  of  Official 
Agricultural  Chemists."  1898.  p.  27-40. 

"  Revised  Regulations  Governing  the  Sampling  and  Classi- 
fication of  Imported  Sugar  and  Molasses.  U.  S.  Treasury 
Department."  Document  No.  2113.] 

Appendix  C 

DIRECTIONS  FOR  MAKING  THE  POLARIZATIONS 

Polariscope. — In  making  polarizations  for  the  purpose  of  revenue 
assessment,  theVentzke-Soleil  color  apparatus  or  a  half-shadow  saccha- 
rimeter  only  may  be  employed.  For  both  instruments,  one  degree  of  rota- 
tion in  a  200  mm.  tube,  at  17.5°,  corresponds  to  a  strength  of  0.26048 
gram  of  sugar  in  100  cc.  of  liquid  ;2  a  sugar  solution  which  contains  26.048 
grams  in  100  cc. — the  so-called  normal  weight — produces  accordingly  a 
rotation  of  iooc.  Therefore,  when  a  solution  of  a  substance  is  examined 
in  a  200  mm.  tube,  and  it  contains  26.048  grams  dissolved  to  make  100  cc., 
the  degrees  of  the  scale  indicate  the  percentage  amount  of  sugar  present. 
If  only  the  half  of  this  normal  weight  is  dissolved,  the  number  of  degrees 
read  off  must  be  doubled  to  obtain  the  correct  per  cent,  of  sugar.  The 
same  is  true  for  those  cases  in  which  the  examination  is  made  in  a  100 
1  Taken  from  Ztschr.  Riibenzucker-Ind.,  46,  410  to  427,  and  435  to  439(1896). 
The  description  of  all  other  methods  employed  in  the  laboratories  of  sugar  facto- 
ries may  be  found  in  the  work  of  Friihling  andSchulz  :  "Anleitung  zur  Untersuchung 
<ier  fur  die  Zuckerindustrie  in  Betracht  kommenden  Rohmaterialien,  Producte, 
Nebenproducte  und  Hiilfssubstanzen."  Braunschweig,  Friedr.  Vieweg  &Sohn,  1897. 
Fifth  edition. 

2  Mohr  cubic  centimeters  are  referred  to.  See  §126  of  this  book.  If  flasks  are  used 
which  are  graduated  in  true  cubic  centimeters,  the  normal  weight  is  25.987  grams  in- 
stead of  26.048  grams.  See  §126  and  Ztschr.  Riibenzucker-Ind.,  41,  514  (1891)  and  46, 
180  (1896). 


468         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

mm.  tube.  On  the  other  hand,  in  investigations  where  the  double  normal 
weight  is  examined  in  a  200  mm.  tube,  or  where  the  simple  normal 
weight  is  examined  in  a  400  mm.  tube,  it  is  necessary  to  take  half  the 
number  of  degrees  read  off. 

The  investigations  are  to  be  made  as  nearly  as  possible  at  the  pre- 
scribed normal  temperature ;  but  slight  deviations  may  be  neglected. 

Proceed  as  follows  in  polarizing  : 

Weighing  out  and  Dissolving  the  Sample ;  making  up  to  100  cc. — 
The  tare  of  the  weighing  receptacle  for  the  sugar,  preferably  a  piece  of 
copper  foil  bent  up  on  two  sides,  is  found  on  an  accurate  balance,  and 
then  the  normal  weight  of  the  sugar,  26.048  grams  is  weighed  out.  As  a 
matter  of  convenience  a  weight  is  used  for  this  which  is  adjusted  to  the 
normal  weight.  In  case  the  sugar  sample  which  is  to  be  tested  is  not 
homogeneous,  it  is  necessary  before  weighing  to  break  any  lumps  present 
and  mix  thoroughly  by  rubbing  with  a  pestle  or  with  the  hand.  It  is 
necessary  to  make  the  weighing  quickly  because,  otherwise,  especially 
in  warm  rooms,  water  may  be  given  off  during  the  process,  and  this 
would  increase  the  polarization.  The  sugar  weighed  out  is  shaken  from 
the  copper  foil  through  a  brass  funnel  into  a  100  cc.  flask;  any  remaining 
particles  are  washed  down  with  about  80  cc.  of  distilled  water  from  a  wash- 
bottle,  having  the  room  temperature,  and  then  the  liquid  in  the  flask  is 
gently  shaken  until  all  is  dissolved,  larger  lumps  being  broken  with  a 
glass  rod.  Any  insoluble  residue,  such  as  particles  of  sand,  may  be 
recognized  as  they  cannot  be  crushed  by  the  rod.  In  withdrawing  the 
rod,  the  adhering  sugar  solution  is  rinsed  down  with  distilled  water. 
Then  the  volume  of  liquid  in  the  flask  is  brought  exactly  to  the  100  cc. 
mark  with  distilled  water.  The  flask  is  held  in  vertical  position  and  the 
water  added  drop  by  drop  until  the  lower  edge  of  the  meniscus  in  the 
neck  of  the  flask  is  exactly  even  with  the  mark  when  this  is  held  on  a 
level  with  the  eye.  After  filling,  the  neck  of  the  flask  is  dried  with  filter- 
paper  and  then  the  liquid  is  well  mixed  by  shaking. 

Clarification. — Sugar  solutions,  which,  after  the  filtration  to  be  de- 
scribed below,  are  not  clear  or  are  so  highly  colored  that  they  are  not 
sufficiently  transparent  in  the  polarization  apparatus,  must,  before  filling 
to  the  mark,  be  clarified  or  decolorized. 

When  a  color  instrument  is  used  loto  20  drops,  or  when  necessary,  even 
more,  of  basic  lead  acetate  solution  is  added  from  a  small  pipette  or  siphon 
wash-bottle,  the  amount  depending  on  the  nature  of  the  sugar  and  the 
intensity  of  the  light  from  the  illuminating  lamp  employed.  If  clarifi- 
cation cannot  be  accomplished  in  this  way,  the  addition  of  an  equal  vol- 
ume of  alum  solution  follows  the  lead  acetate,  or  a  few  cubic  centimeters 
of  alum  solution  may  be  added  first,  and  then  a  larger  volume  of  the  basic 
lead  acetate  solution  than  before,  until  a  filtrate  is  secured  which  is  nearly 
white  or  yellowish  white.  If  the  solutions  cannot  be  clarified  in  this  way, 
then  basic  lead  acetate  alone  is  used  and  the  filtrate  is  mixed  with  the 
smallest  amount  of  extracted  blood  charcoal  ( i  to  3  grams  at  most),  or 


SACCHARIMETRY  469 

with  bone-black  dried  at  120°.  In  this  case,  the  polarization  must  be  in- 
creased by  the  amount  of  the  absorption  coefficient  of  the  charcoal  which 
must  be  found  when  it  is  purchased. 

If  a  half -shadow  apparatus  is  employed,  the  addition  of  3  to  5  cc.  of  a 
thin  alumina  cream  along  with  a  little  basic  lead  acetate  is  usually  suffi- 
cient. Only  when  the  sugar  solutions  are  very  nighty  colored  is  it  neces- 
sary to  employ  the  same  clearing  method  given  for  the  color  instrument. 
It  is  scarcely  necessary  to  proceed  to  the  application  of  blood-  or  bone- 
charcoal  for  the  half-shadow  instruments,  since  rather  dark  sugar  solu- 
tions may  be  polarized  in  these. 

After  clarification,  the  inside  of  the  neck  of  the  flask  is  washed  down 
with  water  from  a  wash-bottle  and  the  solution  is  made  up  to  the  mark  in 
the  manner  described.  Then  any  drops  of  water  clinging  to  the  inside 
of  the  neck  are  wiped  out  by  aid  of  filter-paper,  and  the  contents  are 
thoroughly  mixed  by  shaking  after  closing  the  neck  with  the  finger. 

With  reference  to  clarification,  the  following  general  remarks  hold  for 
both  kinds  of  instruments  : 

1.  The  greater  the  intensity  of  the  light  used  with  the  instrument,  the 
less  will  be  the  decolorization  required  by  the  liquid.    Petroleum,  gas, 
incandescent,  or  electric  lamps  constructed  for  the  purpose  may  be 
used.  With  half-shadow  instruments,  it  is  necessary  to  purify  the  light 
from  other  than  yellow  rays  by  aid  of  a  chromate  plate  or  chromic  acid 
solution  furnished  with  the  apparatus.     With  application  of  incan- 
descent gas  light  this  addition  is  always  necessary. 

2.  When  using  basic  lead  acetate  for  clarification,  a  large  excess  must 
never  be  added.     With  a  little  practice,  one  learns  when  to  stop  with 
the  acetate.     But,   if  too  much  basic  lead  acetate  has  been  added, 
the  excess  must  be  precipitated  by  addition  of  alum  solution  in  the 
manner  shown  above. 

3.  The  action  of  the  clearing  solutions  is  the  stronger,  the  more  per- 
fectly the  mixture  is  shaken  after  filling  to  the  mark. 

Filtration. — Proceed  next  to  filtration  of  the  liquid,  which  is  done 
by  aid  of  a  paper  filter  in  a  glass  funnel.  The  funnel  is  placed  over  a  so- 
called  filtering  cylinder  which  receives  the  liquid,  and  during  the  opera- 
tion is  covered  with  a  glass  plate,  or  watch-glass,  to  prevent  evapora- 
tion. The  funnel  and  cylinder  must  be  perfectly  dry  ;  any  moisture 
present  would  have  the  effect  of  diluting  the  100  cc. 

It  is  convenient  to  have  the  filter  large  enough  to  receive  the  whole 
loo  cc.  of  liquid  at  one  time  ;  it  is  also  recommended,  unless  the  paper  is 
very  thick,  to  use  a  double  filter.  The  first  drops  which  pass  through  are 
thrown  away,  as  they  are  turbid  and  modified  by  the  moisture  of  the 
paper.  If  what  follows  is  also  turbid,  it  must  be  returned  to  the  funnel 
until  a  clear  filtrate  runs  through.  It  is  absolutely  necessary  to  observe 
these  precautions,  because  an  accurate  polarimetric  observation  can  be 
made  only  with  a  clear  liquid. 

Filling  the  200  nun.  Tube. — After  a  clear   solution  is  secured  in  the 


470        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

manner  described  above,  the  tube  which  is  used  in  the  polarimetric  deter- 
mination is  filled  with  the  liquid  necessary  from  the  filtrate  in  the 
cylinder. 

As  a  rule,  a  200  mm.  tube  is  employed  ;  but  with  solutions,  which,  in 
spite  of  all  efforts  at  clarification,  are  still  turbid  or  dark,  a  100  mm.  tube 
is  preferable. 

These  observation  tubes  are  made  of  brass  or  glass  ;  they  are  closed  at 
both  ends  by  means  of  round  glass  plates,  so-called  cover-glasses.  The 
cover-glasses  are  held  by  means  of  screw  caps,  or  by  a  spring  cap  which 
is  shoved  over  the  tube  and  is  held  in  place  by  the  spring. 

The  tubes  must  be  most  carefully  cleaned  and  dried.  The  cleaning  is 
most  easily  accomplished  by  washing  with  water  and  then  by  pushing  dry 
wads  of  filter-paper  through  them  by  aid  of  a  wooden  rod.  The  cover- 
glasses  must  he  polished  perfectly  bright  and  must  not  show  any  imper- 
fect places  or  scratches.  Avoid  warming  the  tube  by  the  hand  when  it  is 
filled.  Therefore,  hold  the  tube,  which  is  closed  below,  by  only  two 
fingers,  and  fill  it  so  the  liquid  meniscus  projects  above  the  upper  opening, 
then  wait  a  short  time  to  allow  any  air  bubbles  to  escape  and  push  on  the 
cover-glass  from  one  side  in  a  horizontal  direction.  The  cover- glass 
must  be  put  on  so  quickly  and  carefully  that  no  air  bubble  can  form 
under  it.  If  it  is  not  satisfactorily  done  the  first  time  the  operation  must 
be  repeated,  after  having  cleaned  and  dried  the  cover-glass  and  filled  up 
the  meniscus  with  a  few  drops  more  of  liquid.  After  bringing  the  cover- 
glass  in  place,  the  tube  is  closed  with  the  cap.  If  this  is  accomplished 
by  a  screw  cap  the  greatest  care  must  be  taken  to  turn  it  on  only  so  far 
as  is  necessary  to  hold  the  cover  in  firm  position  ;  if  it  is  pressed  too  hard, 
the  cover-glass  may  become  optically  active  and  an  incorrect  result  be 
found  on  polarization.  If  the  screw  has  been  turned  too  far,  it  is  not 
sufficient  simply  to  loosen  it,  but  some  time  must  be  allowed  to  pass 
before  the  polarization  can  be  made,  since  the  glass  often  loses  the  im- 
parted polarizing  power  but  slowly.  To  be  perfectly  certain,  the  obser- 
vation should  be  repeated  several  times  after  intervals  of  ten  minutes, 
until  the  result  shows  no  further  change. 

Preparation  of  the  Instrument  for  Observation. — After  filling  the 
tube  it  should  be  held  up  toward  the  light  to  see  if  the  field  of  view 
appears  perfectly  round,  and  if  any  part  of  the  rubber  ring  placed  under 
the  cap  to  diminish  the  pressure  on  the  cover-glass  extends  over  the  open- 
ing in  the  metallic  ring.  If  the  rubber  is  found  to  project  in  this  way  a 
new  dry  tube  with  a  larger  ring  opening  should  be  taken  and  filled  anew. 
The  apparatus  is  then  made  ready  for  the  observation.  It  should  be 
placed  in  a  room,  the  windows  of  which  may  be  darkened  as  far  as  possi- 
ble by  curtains,  so  that  the  eye  will  not  be  disturbed  by  outside  light 
during  the  observation.  Care  should  be  taken  to  have  the  lamp  which 
furnishes  the  light  for  the  apparatus  in  good  condition.  The  lamp  is 
placed  at  a  distance  of  15  to  20  cm.  from  the  instrument,  and  after  light- 
ing it,  wait  at  least  a  quarter  of  an  hour  before  beginning  the  observations. 
Any  changes  in  the  character  of  the  flame,  as  well  as  a  change  of  distance 


SACCHARIMETRY  471 

between  the  lamp  and  polariscope,  or  turning  the  wick  or  the  flame  up 
or  down,  or  any  movement  or  turning  of  the  lamp,  affects  the  results  of 
the  observations.1 

By  moving  the  telescope  at  the  front  end  of  the  instrument  it  is  so  ad- 
justed that  the  hair  line,  which  divides  the  field  of  view  into  two  halves, 
appears  clearly  defined.  The  eye  should  not  be  held  right  at  the  ocular 
of  the  telescope,  but  at  a  distance  of  i  to  3  cm.,  and  during  the  observa- 
tion the  whole  body  should  be  in  a  perfectly  comfortable  position,  since 
any  unnatural  position  leads  to  a  strain  which  disturbs  the  eye.  If  the 
apparatus  is  properly  adjusted  the  field  of  view  is  round  and  sharply  de- 
fined. One  should  not  be  satisfied  with  a  partial  fulfilment  of  these 
conditions,  but  should  change  the  position  of  the  instrument,  the  lamp 
or  the  telescope,  as  necessary,  until  the  desired  end  is  reached. 

Zero  Point  Adjustment. — Then  proceed  to  the  determination  of  the 
zero  point.  \Vith  beginners  it  is  advisable  to  place  a  tube  filled  with 
water  in  the  instrument,  as  thereby  the  field  of  view  is  enlarged  and  the 
observation  made  easier. 

With  a  color  instrument,  finding  the  so-called  transition  tint  precedes 
the  actual  zero  point  adjustment.  To  this  end  the  screw  head  on  the 
right  of  the  apparatus  is  turned  until,  with  a  little  practice,  a  certain 
easily  recognized  light  blue  or  blue  violet  shade  is  secured  at  about  the 
right  zero  position. 

The  sharp  zero  point  adjustment  is  made  by  turning  the  screw  head 
under  the  telescope,  to  and  fro,  until,  at  the  right  point,  the  two  halves 
of  the  field  of  view  have  the  same  tint  in  a  color  instrument,  or  are  equally 
dark  in  a  half-shadow  instrument. 

The  result  of  the  zero  point  adjustment  is  determined  in  the  same  man- 
ner in  both  forms  of  instrument.  This  result  is  read  off  on  the  gradu- 
ated scale  provided  with  a  vernier,  by  means  of  an  observing  telescope, 
the  scale  being  sharply  illuminated  by  aid  of  a  candle  flame.  On  the 
fixed  vernier  ten  divisions  correspond  in  length  with  nine  divisions  on 
the  scale  ;  the  zero  point  of  the  vernier  shows  the  whole  number  of  de- 
grees, while  the  vernier  divisions  serve  to  determine  the  tenths  to  be 
added.  If  the  zero  point  of  the  apparatus  is  correctly  adjusted  the  point 
indicating  it  must  coincide  with  the  zero  of  the  vernier.  If  this  is  not 
the  case  the  deviation  must  be  noted  and  afterwards  must  be  used  to  cor- 
rect the  polarization  reading. 

One  must  not  be  satisfied  with  a  single  zero  point  reading,  but  five  or 
six  readings  are  made,  and  the  mean  of  the  deviations  is  calculated.  If 
single  readings  show  a  variation  of  more  than  three-tenths  of  a  division 
from  the  mean,  they  are  left  out  of  consideration  as  incorrect.  Between 
two  readings  the  eye  should  be  allowed  to  rest  twenty  to  forty  seconds. 

If  a  number  of  analyses  are  to  be  made  in  succession  it  is  not  necessary 
to  find  the  zero  point  before  each  one,  but  it  is  sufficient  if  this  is  done 
after  the  lapse  of  an  hour. 

1  This  is  not  the  case  if  the  path  of  the  rays  through  the  instrument  is  correct, 
according  to  §96  of  this  book.     See  also  §129. 


472         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

Polarization  of  the  Solution. — After  the  zero  point  has  been  found  the 
tube  is  filled  with  the  sugar  solution  and  placed  in  the  apparatus.  The  tele- 
scope is  again  focused  until  the  dividing  line  between  the  fields  is  dis- 
tinctly visible  and  a  perfectly  round  image  of  the  field  of  view  is  secured. 
If  the  field  appears  dim,  even  after  change  in  the  focus,  it  is  necessary  to 
repeat  the  work  from  the  beginning.  But  if  a  clear  image  is  obtained  the 
screw  head  under  the  telescope  is  turned  until  uniformity  in  tint  is  se- 
cured in  a  color  instrument,  or  agreement  in  shade  in  the  half-shadow 
instrument.  Then  the  nearest  number  of  degrees  is  read  off  on  the  scale 
and  the  tenths  on  the  vernier.  Five  or  six  single  observations  are  made 
as  before,  at  intervals  of  ten  to  forty  seconds,  and  the  mean  of  these  taken 
as  the  final  result  of  the  polarization.  If  the  zero  point  did  not  stand  at 
exactly  the  right  place,  the  variation  in  the  reading  must  be  added  if  it 
was  toward  the  left,  and  must  be  subtracted  if  it  was  shoved  to  the  right ; 
also,  in  case  bone-black  was  employed  in  the  clarification,  a  correction 
must  be  made  as  explained  above. 

Control  of  the  Apparatus. — Every  polarizing  instrument  must  be  tested 
before  its  first  use,  and  also  afterward,  from  time  to  time,  especially  if  it 
has  been  shaken  or  jarred,  to  determine  its  accuracy,  and  this  is  done  by 
finding  the  zero  point  and  examining  the  scale  by  aid  of  so-called  normal 
quartz  plates  whose  polarization  is  known.  The  test  may  be  made  also 
by  use  of  26.048  grams  of  pure  sugar,  the  solution  of  which  should  polar- 
ize exactly  100  degrees  when  the  zero  point  is  placed  correctly. 

Appendix  A 

DIRECTIONS  FOR  THE  REVENUE  OFFICIALS  "" 

in  testing   sugar  sirups  for  invert  sugar,  and  in  fixing  the  quotient  for 
sirup  containing  less  than  2  per  cent,  of  invert  sugar. 

i.  Testing  Sugar  Sirups  for  Invert  Sugar 

Exactly  10  grams  of  the  sirup,  previously  made  thin  by  wanning,  are 
weighed  into  a  porcelain  dish  and  brought  into  solution  by  stirring  after 
addition  of  50  cc.  of  warm  water.  As  a  rule,  the  solution  does  not  re- 
quire filtration,  even  if  it  appears  cloudy.  It  is  poured  into  an  Erlenmeyer 
flask  of  about  200  cc.  capacity,  or  into  a  correspondingly  large  porcelain 
dish,  and  then  50  cc.  of  Fehling  solution  is  added. 

The  Fehling  solution  is  made  by  mixing  equal  volumes  of  blue  vitriol 
solution  (34.639  grams  of  crystallized  copper  sulphate  to  make  500  cc. ), 
and  alkali-Rochelle  salt  solution  ( 173  grams  of  crystallized  Rochelle  salt 
in  400  cc.,  this  solution  mixed  with  100  cc.  of  a  sodium  hydroxide  solu- 
tion which  contains  500  grams  in  a  liter).  The  two  liquids,  which  may  be 
obtained  from  chemical  dealers,  must  be  kept  separate  ;  of  each  one,  25 
cc.  is  taken  by  a  special  pipette  and  added  to  the  solution  of  the  sugar 
sirup  with  stirring.  If  a  large  number  of  tests  are  to  be  made  at  one  time 
the  two  constituents  of  the  Fehling  solution  may  be  mixed  with  each 
other  in  correspondingly  large  amount;  but  the  use  of  such  a  mixture  is 
allowable  only  within  three  days,  l>ecause  on  longer  standing  it  becomes 
valueless  for  analysis. 


SACCHARIMETRY  473 

The  liquid  mixed  with  Fehling  solution  is  heated  in  a  flask  on  gauze 
over  a  Bunsen  burner  or  a  good  alcohol  lamp,  brought  to  boiling  and  kept 
in  ebullition  two  minutes.  This  time  of  boiling  must  not  be  shortened. 

Then  the  lamp  is  removed  and  the  liquid  is  allowed  to  stand  at  rest  a 
few  minutes  to  permit  a  precipitate  to  settle  ;  the  flask  is  held  toward  the 
light  to  see  whether  or  not  a  blue  color  remains.  If  there  is  still  copper 
in  the  solution,  which  is  shown  by  a  blue  color,  the  solution  contained 
less  than  2  per  cent,  of  invert  sugar. 

The  color  is  more  easily  recognized  by  holding  a  sheet  of  white  paper 
back  of  the  flask  and  examining  it  in  reflected  light. 

If,  after  boiling,  the  liquid  appears  yellowish  green  or  brownish  it  is 
possible  that  undecomposed  copper  solution  is  still  present,  but  masked 
in  color  by  the  yellowish  brown  color  of  the  sirup.  In  such  cases,  pro- 
ceed as  follows  : 

A  small  filter  is  made  of  good  thick  filter-paper,  placed  in  a  glass  funnel 
and  moistened  with  a  little  water  so  that  it  may  be  pressed  against  the 
edge  of  the  funnel.  The  funnel  is  placed  over  a  test-tube  ;  then,  about 
10  cc.  of  the  boiled  liquid  is  filtered,  and  to  the  filtrate  about  the  same 
volume  of  acetic  acid  and  one  or  two  drops  of  an  aquequs  solution  of 
potassium  ferrocyanide  are  added.  If  an  intense  red  color  appears  in  the 
filtrate,  copper  is  still  in  solution  and  it  is  so  shown  that  the  sirup  con- 
tains less  than  2  per  cent  of  invert  sugar. 

2.  Determination  of  the  Quotient  for  Sugar  Sirup  Containing  Less  than 
2  Per  Cent,  of  Invert  Sugar 

The  quotient  (or  coefficient  of  purity)  is  that  per  cent,  of  sugar  in  the 
solids  of  the  sirup  which  may  be  calculated  from  the  polarization  and 
the  specific  gravity  on  the  Brix  scale. 

a.    To  Find  the  Specific  Gravity  in  Brix  Degrees. 

In  a  tared  beaker,  weigh  off  200  to  300  grams  of  the  sirup  to  be  tested, 
loo  to  200  cc.  of  warm  distilled  water  is  added,  the  mixture  is  carefully 
stirred  (to  avoid  breaking  the  glass)  until  the  whole  is  brought  into  solu- 
tion, and  then  the  beaker  is  placed  in  cold  water  until  the  contents  have 
cooled  to  the  room  temperature.  Then  the  beaker  is  placed  on  a  balance, 
and  water  is  carefully  added  from  a  wash-bottle  until  the  whole  weight 
of  added  water  is  just  equal  to  that  of  the  sirup  taken.  For  example,  if 
251  grams  of  sirup  were  taken  for  testing,  then  water  must  be  added  until 
the  liquid  weighs  502  grams.  After  adding  the  water  the  liquid  is  stirred 
and  filled  then  into  the  specific  gravity  cylinder  so  far  that,  after  immer- 
sion of  the  Brix  spindle,  it  does  not  reach  quite  to  the  upper  edge.  The 
cylinder  must  be  placed  in  a  vertical  position  so  that  the  spindle  will 
float  freely  without  touching  the  sides.  The  spindle  is  immersed  slowly, 
and  care  must  be  taken  not  to  moisten  that  part  of  the  stem  which  remains 
above  the  liquid  after  the  spindle  has  come  to  rest.  When  this  condition 
is  reached,  the  saccharometer  degrees  are  read  off  at  the  point  where  the 
liquid  meniscus  cuts  the  stem. 


474        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 


The  number  of  degrees  read  off  on  the  spindle  holds  for  the  normal 
temperature  of  17.5°  C.  If  the  liquid  does  not  happen  to  have  this 
normal  temperature,  the  degrees  read  off  must  be  corrected  by  aid  of  the 
following  table,  after  the  true  temperature  is  found  by  means  of  a  ther- 
mometer attached  to  the  body  of  the  spindle. 

After  the  correction,  the  Brix  degrees  are  to  be  rounded  off  in  tenths, 
by  considering  five  or  more  hundredths  as  a  full  tenth,  and  smaller 
fractions  neglected. 

The  number  of  degrees  read  off  are  to  be  multiplied  by  2,  because  the 
liquid  employed  in  the  test  had  been  diluted  with  an  equal  weight  of 
water. 

TABLE  FOR  THE  CORRECTION  OF  BRIX  DEGREES  FOR  TEMPERATURES 
DIFFERENT  FROM  THE  NORMAL  TEMPERATURE  (17.5°  C.) 


At  a  centigrade 
temperature  of 

and  at 

25 

30 

35 

40 

50 

60 

70 

75 

Brix  degrees. 

There  must  be  taken  from  the  saccharometer  readings  : 

Degrees. 

0° 

0.72 

0.82 

0.92 

0.98 

I.  II 

1.22 

1.25 

1.29 

5 

0.59 

0.65 

0.72 

0-75 

0.80 

0.88 

0.91 

0.94 

10 

0-39 

0.42 

0-45 

0.48 

0.50 

0.54 

0.58 

0.61 

II 

0-34 

0.36 

0-39 

0.41 

0.43 

0.47 

0.50 

0-53 

12 

0.29 

0.31 

0-33 

0-34 

0.36 

0.40 

0.42 

0.46 

13 

0.24 

0.26 

0.27 

0.28 

0.29 

0.33 

0.35 

o-39 

H 

0.19 

0.21 

0.22 

0.22 

0.23 

0.26 

0.28 

0.32 

15 

0.15 

o.  16 

0.17 

o.  16 

0.17 

0.19 

0.21 

0.25 

16 

O.IO 

O.I  I 

0.12 

0.12 

0.12 

0.14 

o.  16 

0.18 

17 

0.04 

0.04 

0.04 

0.04 

0.04 

0.05 

0.05 

0.06 

There  must  be  added  to  the  saccharometer  readings  : 


18 

0.03 

0.03 

0.03 

0.03 

0.03 

0.03 

0.03 

0.02 

19 

0.10 

O.  IO 

O.IO 

O.IO 

O.IO 

O.IO 

0.08 

O.O6 

20 

0.18 

0.18 

0.18 

0.19 

0.19 

0.18 

0.15 

O.I  I 

21 

0.25 

0.25 

0.25 

0.26 

0.26 

0.25 

O.22 

0.18 

22 

0.32 

0.32 

0.32 

0.33 

0-34 

0.32 

0.29 

0.25 

23 

0-39 

0-39 

0-39 

0.40 

0.42 

0-39 

0.36 

o.33 

24 

0.46 

0.46 

0.47 

0.47 

0.50 

0.46 

0.43 

0.40 

25 

0.53 

0-54 

0-55 

0-55 

0.58 

o.54 

0.51 

0.48 

26 

0.60 

0.61 

0.62 

0.62 

0.66 

0.62 

0.58 

0-55 

27 

0.68 

0.68 

0.69 

0.70 

0.74 

0.70 

0.65 

0.62 

28 

0.76 

0.76 

0.78 

0.78 

0.82 

0.78 

0.72 

0.70 

29 

0.84 

0.84 

0.86 

0.86 

0.90 

0.86 

0.80 

0.78 

30 

0.92 

0.92 

0.94 

0.94 

0.98 

0.94 

0.88 

0.86 

SACCHARIMETRY  475 

b.     Polarization 

In  the  polarization  of  sugar  sirups,  because  of  the  dark  color,  the  direc- 
tions given  in  Appendix  C  for  determination  must  be  modified  in  these 
respects : 

Only  the  half  weight,  13.024  grams,  is  taken  in  testing  sugar  sirup. 
This  is  weighed  into  a  porcelain  dish  and  treated  with  40  to  50  cc.  of 
lukewarm  distilled  water,  and  stirred  with  a  glass  rod  until  it  has  dis- 
solved completely.  Then  the  liquid  is  washed  into  the  flask  and  before 
filling  to  the  mark  is  clarified. 

For  the  clarification  about  5  cc.  of  basic  lead  acetate  solution  is  run 
first  into  the  flask.  If  after  the  precipitate  has  settled,  which  follows  in 
a  few  minutes,  the  liquid  is  still  too  dark  the  addition  of  the  lead  acetate 
is  continued  until  the  desired  brightness  is  secured.  As  much  as  12  cc. 
of  the  basic  acetate  is  often  required  for  this.  But  it  must  be  observed 
that  the  basic  acetate  must  be  added  in  sufficient,  but  not  in  excessive, 
quantity  ;  each  new  drop  added  must  produce  a  precipitate  in  the  liquid. 

If  it  is  found  that  the  latter  cannot  be  sufficiently  clarified  by  the  addi- 
tion of  basic  lead  acetate  to  be  polarized  in  the  200  mm.  tube,  an  effort 
should  be  made  to  polarize  it  in  the  100  mm.  tube.  If  this  is  likewise 
impossible  a  new  sample  should  be  prepared,  which  is  treated  with  about 
10  cc.  of  an  alum  or  tannic  acid  solution  before  the  addition  of  the  basic 
lead  acetate  ;  these  solutions  produce  heavy  precipitates  with  basic  lead 
acetate,  which  have  a  clarifying  effect  and  permit  the  use  of  larger  quan- 
tities of  the  lead  solution. 

After  the  polarization  is  made  the  number  of  degrees  read  off  must  be 
multiplied  by  2,  since  only  the  half-normal  weight  was  taken  for  the  test. 
If  a  zoo  mm.  tube  was  employed  in  place  of  the  200  mm.  tube  the  num- 
ber of  degrees  read  off  must  be  multiplied  by  4. 

c.     Calculation  of  the  Quotient 

If  the  observed  number  of  Brix  degrees  be  designated  by  B,  and  the 
degree  of  polarization  by  P,  then  the  quotient  is  calculated  by  the  for- 
mula, Q  •= ^ — .  In  stating  the  final  result  smaller  fractions  than  full 

D 

tenths  are  omitted. 

Illustration  of  the  Determination  of  the  Quotient. — 200  grams  of  a 
sugar  sirup  are  diluted  with  200  grams  of  water.  The  Brix  spindle  indi- 
cates 35.2°  at  a  temperature  of  21°  C  ;  from  the  above  table  0.25  must  be 
added  ;  this  gives  then  35.45°,  or  rounded  off  35.5°,  and  after  multiplying 
by  2,  71°  Brix.  The  polarization  of  the  half-normal  weight  in  a  200  mm. 
tube  gave  25.2°;  the  true  polarization  is  then  25.2  X  2  =  50.4°.  The 

quotient  calculated  is  therefore  —  -  =  70.9. 

Final  Provision 

Revision  reports  must  contain  the  following  data  :  the  result  of  the 
test  for  invert  sugar,  the  number  of  degrees  read  off  on  the  areometer, 


476         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

the  temperature  of  the  solution,  the  calculated  areometer  degrees  for  the 
undiluted  sirup,  the  polarization  for  the  whole  normal  weight  and  the 
quotient. 

Appendix  B 

DIRECTIONS  FOR  CHEMISTS 

I.  In  determining  the  quotient  for  sirups  containing  2  per  cent,  or  more 
of  invert  sugar,  and  the  quotient  of  sirups  to  be  examined  for  raffi- 
nose, 

also, 

II.    In  determining  the  amount  of  sugar  in  crystal  sugar  supposed  to  con- 
tain raffinose. 

I.     The  Quotient  for  Sirups 

According  to  the  regulations  provided  by  the  sugar  tax  law  the  deter- 
mination of  the  quotient  for  a  sirup  shall  be  left  to  a  chemist  when  : 

a.  There  is  no  official  properly  qualified  to  determine  the  quotient  at 
the  point  of  declaration  or  at  the  office  to  which  the  sample  is  sent; 

b.  The  sirup  contains  2  per  cent,  or  more  of  invert  sugar; 

c.  The  one  presenting  the  sample  asks  for  the  calculation  of  the  quo- 
tient from  the  amount  of  pure  sugar  chemically  determined. 

When  samples  are  sent  from  the  revenue  office  to  a  chemist  he  must  be 
informed  as  to  which  one  of  the  above  grounds  the  investigation  is  called 
for,  and  besides  in  cases  coming  under  r,  whether  or  not  the  application 
of  the  raffinose  formula  is  allowable,  according  to  the  directions  of  #2, 
section  5  of  the  last  part  of  the  Rules  of  Procedure,  where  2  or  more 
per  cent,  of  invert  sugar  may  be  present. 

In  cases  under  a  the  chemist  must  proceed  as  in  Appendix  A  of  the 
Rules  of  Procedure,  but  with  the  condition  that  the  Brix  degrees  are  to 
be  found  as  given  in  the  following  section  i . 

In  cases  under  b  the  quotient  must  be  found  as  explained  in  the  follow- 
ing section  i. 

In  cases  under  c,  as  far  as  the  use  of  the  raffinose  formula  is  allowable, 
the  method  of  section  2  below  must  be  followed,  otherwise  the  method  is 
according  to  the  provisions  of  section  i .  If  the  propriety  of  using  the 
raffinose  formula  depends  on  whether  or  not  the  sirup  contains  less  than 
2  per  cent,  of  invert  sugar,  then  the  sirup  must  be  tested  according  to  the 
method  of  section  i  in  Appendix  A. 

/.  Determination  of  the  Quotient  in  Sirups  Containing  2  Per  Cent,  or 
More  of  Invert  Sugar 

In  the  investigation  of  sirups  containing  2  per  cent,  or  more  of  invert 
sugar  the  Brix  degrees  must  be  calculated  from  the  specific  gravity  of  the 
undiluted  sirup  found  by  aid  of  a  pycnometer. 

If  a  quotient  of  70  or  more  is  found  from  the  number  of  Brix  degrees 
and  the  direct  polarization  to  be  always  made  in  connection,  then  any 
further  investigation  is  to  be  dropped,  as  this  would  only  lead  to  an  in- 
crease of  the  quotient. 


SACCHARIMETRY  477 

But  if  a  quotient  below  70  is  found  in  this  preliminary  test  then  the 
exact  determination  of  the  amount  of  sugar  is  called  for.  In  this  it  is 
not  the  saccharose  alone  which  is  to  be  calculated  as  sugar,  as  in  factory 
work,  but  the  invert  sugar  present,  which  is  calculated  to  cane-sugar  by 
the  subtraction  of  l  K,  is  to  be  added  to  the  latter  and  the  sum  then  taken 
as  the  basis  of  the  calculation. 

In  sirups  the  invert  sugar  is  often  inactive,  but  it  may  have  the  normal 
left  rotation  and,  therefore,  make  the  polarization  of  the  cane-sugar  pres- 
ent appear  too  low.  For  this  reason  it  is  not  permissible  in  the  exami- 
nation of  sirups,  to  proceed  as  was  suggested  by  Meissl  for  solid  sugar- 
cane sugars,  to  multiply  the  invert  sugar  by  0.34,  and  to  add  the  prod- 
uct obtained  to  the  polarization.  If  one  should  proceed  in  this  way,  the 
sugar  content  of  a  sirup  would,  in  many  cases,  be  made  to  appear  too 
high.  But  the  possibility  must  always  be  kept  in  mind  that,  in  conse- 
quence of  the  left-hand  rotation  of  invert  sugar,  in  presence  of  much  of 
the  latter  the  cane-sugar  content  will  be  found  much  too  low.  In  con 
sideration  of  these  conditions,  it  appears  in  general  that  the  calculation 
of  the  total  sugar  from  the  polarization  and  the  invert  sugar  found  is 
allowable  only  in  those  cases  wyhere  the  amount  of  invert  sugar  does  not 
exceed  a  certain  limit.  As  an  illustration,  in  presence  of  6  per  cent,  of 
invert  sugar  the  polarization  of  beet-sugar  could  be  6  X  °-34  =  2-°4 
percent,  too  low.  It  is  then  advisable,  in  general,  to  abandon  the  optical 
method  for  sugar  determination  in  sirups  and  to  apply  a  gravimetric 
estimation  for  which  a  method  that  can  be  quickly  carried  out  is  given 
below  under  a. 

But  an  exception  must  be  made  when  starch  sugar  is  added  to  the 
sirup.  As  we  are  unable  to  determine  accurately  the  amount  of  starch 
sugar  present,  and  as,  in  addition,  the  reducing  power  of  this  sugar,  which 
in  the  commercial  product  corresponds  to  a  content  of  40  to  60  per  cent, 
of  dextrose,  remains  practically  constant  under  the  conditions  which  are 
applied  in  the  inversion  of  sirup  for  carrying  out  the  gravimetric  method, 
it  follows  that  in  cases  where  this  sugar  is  added,  the  gravimetric  method 
for  determination  of  the  total  sugar  content,  or  the  quotient,  can  no  longer 
be  applied.  It  would  lead,  on  the  contrary,  to  gross  errors,  and  sirups 
with  a  quotient  above  70,  with  a  certain  amount  of  starch  sugar  added, 
would  be  made  to  appear,  when  tested  in  this  way,  as  having  a  quotient 
below  70.  With  starch  sugar  present,  the  left-hand  rotation  of  the  in- 
vert sugar  no  longer  affects  the  polarization  as  in  the  case  of  unmixed 
sirup,  because  the  starch  sugar  has  a  much  greater  right-hand  rotating 
power  than  the  other  kinds  of  sugars  which  may  be  there.  To  guard 
against  mistakes  which  are  easily  possible  with  the  mixing  of  starch 
sugar  and  sirups  having  a  quotient  over  70,  the  total  svigar  content,  in  all 
cases  when  starch  sugar  is  added,  must  be  calculated  from  the  polari- 
zation and  the  invert  sugar  determined  directly,  as  explained  below,  under 
b. 

Every  sirup  wrhich  contains  2  per  cent,  or  more  of  invert  sugar  must, 
therefore,  be  tested  to  find  whether  or  not  it  contains  starch  sugar. 


478         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

In  sugar  factories  starch  sirup  is  seldom  added  to  cane-sugar  sirups. 
As  a  rule,  molasses,  which  are  to  be  sent  to  distilleries  or  to  factories  for 
the  extraction  of  sugar,  do  not  contain  starch  sugar,  because  such  sirups 
could  be  worked  only  with  difficulty  in  these  places.  If  the  chemist 
making  the  tests  has  reason  to  believe  from  his  knowledge  of  the  origin 
or  destination  of  the  sugar  sirup  in  question,  and  after  proper  considera- 
tion, can  assume  with  sufficient  certainty  that  it  does  not  contain  starch 
sugar,  then  he  may  omit  the  chemical  tests  which  would  be  called  for. 
But,  in  other  cases,  the  chemical  examination  for  starch  sugar  must  be 
made  in  the  following  manner  : 

The  half  normal  weight  is  dissolved  in  the  100  cc.  flask  in  75  cc.  of 
water,  and  inverted  at  67°  to  70°  C.  by  addition  of  5  cc.  of  hydrochloric 
acid  of  1.19  specific  gravity.  Then  the  flask  is  filled  to  100  cc.,  and  the 
solution  is  decolorized  by  addition  of  ^  to  i  gram  of  blood-  or  bone-char- 
coal which  has  been  washed  with  hydrochloric  acid,  or,  with  dark  sirups, 
with  even  2  or  3  giams,  added  directly  to  the  flask  in  dry  condition.  If 
blood-charcoal  is  used,  its  absorption  factor  for  invert  sugar  must  be  de- 
termined, as  it  is  not  the  same  for  all  kinds,  and  a  corresponding  cor- 
rection made  on  the  polarimeter  reading.  Unadulterated  sirups,  as  found 
by  experience,  show  often  less  than  the  normal  left-hand  rotation,  which 
at  20°  is  0.327  of  the  original  right-hand  rotation,  but  the  amount  is 
always  at  least  the  fifth  part  of  the  original.  Therefore,  only  such  sirups 
shall  be  considered  as  mixed  with  starch  sugar  whose  left-hand  rotation 
after  inversion  is  less  than  one-fifth  of  the  right  rotation  before  inversion. 
For  example,  a  sirup  of  55°  polarization  which,  after  inversion,  shows  a 
rotation  of  less  than  —  11°,  or  even  a  right-hand  rotation,  must  be  con- 
sidered as  mixed  with  starch  sugar. 

a.     Sirups  free  from  starch  sugar 

In  sirups  free  from  starch  sugar  the  determination  of  total  sugar  may 
be  made  in  a  single  operation. 

The  half-normal  weight  ( 13.024  grams)  is  taken  and  dissolved  in  a  100 
cc.  flask  in  75  cc.  of  water,  5  cc.  of  hydrochloric  acid  of  1.19  specific 
gravity  is  added,  and  the  whole  is  warmed  to  67°  or  70°  in  a  water-bath. 
The  flask  is  kept  five  minutes  longer  at  this  temperature  of  67°  to  70° 
and  is  frequently  shaken.  As  the  heating  requires  two  and  one-half 
to  five  minutes,  the  whole  operation  will  consume  seven  and  one-half  to 
ten  minutes  ;  in  any  event  it  should  be  completed  in  ten  minutes.  The 
flask  is  filled  to  the  mark  and  50  cc.  of  the  100  cc.  is  then  diluted  to  i 
liter,  and  25  cc.  of  this  dilute  solution  (corresponding  to  0.1628  gram  of 
substance)  is  taken  in  an  Erlenmeyer  flask  and  neutralized  by  the  addi- 
tion of  25  cc.  of  a  sodium  carbonate  solution  containing  1.7  grams  of  the 
anhydrous  salt  to  the  liter.  Then  50  cc.  of  Fehling's  solution  is  added 
and  the  solution  is  heated  to  the  boiling-point  in  the  same  manner  as  in  the 
invert  sugar  determination,  and  then  kept  three  minutes  in  ebullition. 
The  liquid  should  be  heated  as  quickly  as  possible  by  means  of  a  good 
triple  burner,  using  wire  gauze  and  sheet  asbestos  with  a  ring  cut  out  of 


SACCHARIMETRY 


479 


it,  and  should  require  three  and  one-half  to  four  minutes ;  when  the 
liquid  begins  to  boil  rapidly  a  single  burner  is  exchanged  for  the  triple 
burner.  When  the  boiling  is  complete  the  liquid  in  the  flask  is  diluted 
with  an  equal  volume  of  air-free  distilled  water  and  the  process  is  con- 
ducted in  general  as  in  the  determination  of  invert  sugar.  The  tables 
found  in  the  literature  cannot  be  used  in  the  calculation  of  the  result  be- 
cause they  do  not  obtain  for  invert  sugar,  but  only  for  dextrose,  or  for 
mixtures  of  invert  sugar  and  saccharose  ;  the  cane-sugar  content  of  the 
sirup  corresponding  to  the  copper  obtained  must  be  found  by  use  of  the 
following  table  only,  which  gives  it  directly  in  per  cent.  The  calculation 
of  invert  sugar  into  cane-sugar  is  then  avoided  by  use  of  the  table. 

TABLE  FOR  THE  CALCULATION  OF  CANE-SUGAR  IN  PER  CENT.,  CORRE- 
SPONDING TO  INVERT  SUGAR  PRESENT,  FROM  THE  AMOUNT  OF 
COPPER  WEIGHED,  AFTER  THREE  MINUTES'  BOILING, 
WITH  o.  1628  GRAM  OF  SUBSTANCE  TAKEN 


Copper, 
ing. 

Cane- 
sugar. 
Per  cent. 

Copper, 
mg. 

Cane- 
sugar. 
Per  cent. 

Copper, 
mg. 

Cane- 
sugar. 
Per  cent. 

Copper, 
mg. 

Cane- 
sugar. 
Per  cent. 

79 

24-57 

106 

32.76 

133 

41.04 

160 

49.50 

80 

24.87 

107 

33-06 

134 

41-35 

161 

49.82 

8l 

25.17 

108 

33.36 

135 

41.66 

162 

50.13 

82 

25-47 

109 

33.67 

136 

41.98 

163 

50.45 

83 

25.78 

no 

33-97 

137 

42.29 

164 

50.76 

84 

26.08 

III 

34.27 

138 

42.60 

I65 

5T.08 

85 

26.38 

112 

34.58 

139 

42.91 

166 

51.40 

86 

26.68 

113 

34-88 

140 

43-22 

167 

51.72 

87 

26.98 

114 

35.19 

141 

43-53 

168 

52.04 

88 

27.29 

US 

35-49 

142 

43.85 

169 

52.35 

89 

27.59 

116 

35.8o 

143 

44.16 

170 

52.6/ 

90 

27.89 

117 

36.10 

144 

44.48 

171 

52.99 

9i 

28.19 

118 

36.41 

145 

44.70 

172 

53-31 

92 

28.50 

119 

36-71 

I46 

45-10 

173 

53.63 

93 

28.80 

120 

37-01 

147 

45-42 

174 

53-95 

94 

29.10 

121 

37-32 

148 

45-73 

175 

54-27 

95 

29.40 

122 

37-63 

149 

46.05 

176 

54-59 

96 

29.71 

I23 

37-94 

150 

46.36 

177 

54-91 

97 

30.02 

124 

38-25 

151 

46.68 

178 

55-23 

98 

30.32 

125 

38.56 

152 

46.99 

179 

55-55 

99 

30.63 

126 

38.87 

153 

47-30 

180 

55-87 

100 

30.93 

I27 

39-iS 

154 

47.62 

181 

56.19 

101 

31.24 

128 

39-49 

155 

47-93 

182 

56-51 

102 

31-54 

J29 

39.80 

156 

48.25 

183 

56-83 

103 

31.85 

130 

40.11 

157 

48.56 

184 

57-15 

104 

32.15 

131 

40.42 

158 

48.88 

185 

57-47 

105 

32.45 

132 

40.73 

159 

49-19 

186 

57-79 

480        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 


Copper, 
mg. 

Cane- 
sugar. 
Per  cent. 

Copper 
mg. 

Cane- 
sugar. 
Per  cent. 

Copper, 
mg. 

Cane- 
sugar. 
Per  cent. 

Copper, 
mg. 

Cane- 
sugar. 
Per  cent. 

lS7 

58.11 

207 

64.58 

227 

71.19 

247 

77.85 

188 

58.43 

!  208 

64.91 

228 

71.53 

248 

78.18 

189 

58.75 

209 

65-23 

229 

71.86 

249 

78.52 

190 

59.07 

2TO 

65.56. 

230 

72.19 

250 

78.85 

191 

59.39 

211 

65.89 

23I 

72.52 

251 

79.19 

192 

59-72 

212 

66.22 

232 

72.85 

252 

79-53 

193 

60.04 

213 

66.55 

233 

73-18 

253 

79.88 

194 

60.36 

214 

66.88 

234 

73-51 

254 

80.22 

195 

60.69 

215 

67.21 

235 

73.85 

255 

80.56 

196 

61.01 

216 

67.55 

236 

74.18 

256 

80.90 

197 

6i.33 

217 

67.88 

237 

74-51 

257 

81.24 

198 

61.65 

218 

68.  2  T 

238 

74.84 

258 

81.59 

199 

61.98 

2I9 

68.54 

239 

75-r7 

259 

8L93 

200 

62.30 

220 

68.87 

240 

75-50 

260 

82.27 

201 

62.63 

221 

69.20 

241 

75.83 

261 

82.61 

202 

62.95 

222 

69-53 

242 

76.17 

262 

82.95 

203 

63.28 

223 

69.87 

243    76.51 

263     83.30 

204 

63.60 

224 

70.20 

244    76.84 

264  . 

83-64 

205 

63.93 

225 

70.53 

245 

77.18 

265 

83.98 

206 

64.26 

226 

70.86 

246 

77-51 

266 

84.32 

In  the  calculation  of  the  quotient,  fractions  below  whole  tenths  are 
neglected. 

Example:  25  cc.  of  the  inverted  sugar  sirup  0.1628  gram  of  sub- 
stance, gave  on  reduction  171  mg.  of  copper ;  this  corresponds  to  52.99 
or  rounded  off  52.9  per  cent,  of  sugar.  Assuming  that  the  sirup  showed 
75.6  Brix,  its  quotient  is  69.97,  or  rounded,  69.9. 

b.  Sirups  containing  starch  sugar 

With  sirups  containing  starch  sugar  in  order  to  obtain  the  total  sugar 
content,  the  plan  must  be  adopted,  as  mentioned  above,  of  adding  to  the 
polarization  the  invert  sugar,  which  is  to  be  calculated  from  the  reducing 
action  of  the  sirup  on  Fehling's  solution. 

In  the  determination  of  the  invert  sugar  in  this  case,  a  preliminary 
test  must  be  made  to  learn  how  much  substance  may  be  weighed  out,  as 
the  Fehling  solution  would  not  be  sufficient  for  the  10  grams  usually 
taken.  This  is  most  conveniently  done  by  dissolving  10  grams  of  sirup  to 
make  100  cc.,  and  adding  different  amounts  to  several  portions  of 
Fehling's  solution  of  5  cc.  each  in  a*  many  test-tubes,  to  one  8  cc.,  to 
another  6  cc.,  to  another  4  cc.,  and  to  the  last  2  cc.  On  boiling  now  the 
first  test-tube  which  is  not  decolorized  shows  the  amount  to  be  taken.  If, 
for  example,  reduction  is  not  complete  in  the  tube  with  6  cc.  of  the  solu- 
tion, then  6  grams  is  the  amount  of  sirup  to  be  weighed  out  for  the 


SACCHARIMETRY 


481 


analysis.     The  right  amount  of  substance  is  dissolved  in  50  cc.  of  water, 
mixed  with  50  cc.  of  Fehling's  solution  without  previous  clarification  with 
lead  acetate,  boiled  two  minutes  and  then  treated  in  the  usual  manner  for 
the  determination  of  invert  sugar  in  solid  sugar.     The  amount  of  invert 
sugar  is  calculated  as  follows  : 
Let 
Pol,  =  the  polarization  of  the  substance, 

p       the  amount  of  substance  taken  for  determination  of  invert 
sugar,  which  yields  Cu  grams  of  copper. 

The  amount  of  invert  sugar  may  be  taken  approximately  as  —  ,  and 
may  be  represented  by  A.     We  find  then  from  the  proportion, 


for  R  the  amount  of  invert  sugar  which  is  present  in   100  parts  of  cane- 
sugar  —  invert  sugar. 

The  percentage  amount  of  invert  sugar  in  the  substance  is  given  by 
the  formula 

—  -  X  F=  per  cent,  of  invert  sugar, 

in  which  p  is  the  amount  of  substance  taken,  and  Fa.  factor  from  the 
table  below. 

In  this  table  the  columns  and  lines  are  used,  the  designations  of  which 
come  the  nearest  to  the  values  found  for  A  and  B  ;  at  the  intersecting 
point,  the  factor  Fis  given. 

TABLE  OF  FACTORS  TO  BE  TAKEN  FOR  THE  CALCULATION  OF  INVERT 
SUGAR  IN  PRESENCE  OF  CANE  SUGAR 


Invert  sugar  in 
100  parts  of  total  sugar  =  B. 

Milligrams  or  invert  sugar  =  A. 

200 

175 

150 

125          ioo 

75 

5° 

100                             56.4       55.4 

54-5 

53-8     53-2 

53-o 

53-° 

9° 

56.3      55-3 

54-4 

53-8     53-2 

52.9 

52.9 

80 

56.2      55.2 

54-3      53-7      53-2 

52.7 

52.7 

70 

56.1       55-1 

54-2      53-7      S3-2 

52-6 

52.6 

60 

55-9      55-0 

54.i      53-6     53-  1 

52.5 

52.4 

50 

55-7 

54-9 

54-0 

53-5      S3-1 

52.3 

52.2 

40 

55-6 

54-7 

53.8 

53-2      52.8 

52.1 

51-9 

30 

55-5 

54-5 

53-5 

52.9      52.5 

51-9 

51-6 

20 

55-4 

54-3 

53-3 

52.7      52-2 

51-7 

5r-3 

10 

54-6 

53-6 

53-1 

52.6      52.1 

51-6 

51-2 

9 

54-1 

53-6 

52.6 

52.1      51-6 

51-2 

50.7 

8 

53-6 

53-i 

52.1 

51.6      51-2 

50.7 

50.3 

7 

53-6 

53-1 

52.1 

5L2      50.7 

50.3 

49-8 

6 

53-1 

52.6 

51-6 

50.7      50-3 

49-8 

48.9 

5 

52-6 

52.1 

51-2 

50.3      49-4 

48.9 

48.5 

4 

52.1 

51-2 

50.7 

49.8      48.9 

47-7 

46.9 

3 

50.7 

50.3 

49-8 

48.9     47-7 

46.2 

45-1 

2 

49-9 

48.9      48.5 

47-3      45-8 

43-3 

40.0 

I 

47-7 

47.3 

46.5 

45-i      43-3 

41.2 

38.1 

482         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

Example  :  Assume  that  the  polarization  of  the  sirup  is  86.4,  and  tha 
for  3.256  grams  of  substance  taken  (/>),  the  amount  of  copper  found  (Cu) 
is  0.290,  then  : 

p  X  Pol  \  /  3.256 

'  0.145  +  '    L- 


/    .        p  X  Pol  \  / 

(A  +  '-T5^-j  :  A  =  ( 


2.958  :  0.145  =  ioo  :  4.9; 
therefore,  B  =  4.9. 

The  nearest  value  in  the  table  to  A  =  0.145  *s  T5°  mg  :  the  number  5 
is  the  nearest  to  4.9,  the  invert  sugar  in  100  parts  of  total  sugar  ;  at  the 
point  of  intersection  of  the  line  5  with  the  column  headed  150  mg.  we 

find  the  factor  51.2.    If  this  is  substituted  in  the  formula  —  X  F  weob- 

P 

tain  -  —  X  5L2  =  4.56  per  cent,   of  invert   sugar.     Then   the   invert 

sugar  is  calculated  to  cane-sugar  by  subtraction  of  Vao.  an(l  tlle  result  ob- 
tained (4-56  —  0.23^=4.33)  added  to  that  for  the  polarization.  From 
the  sum  and  the  Brix  degrees  the  quotient  is  found  in  the  usual  way. 

2.  Determination  of  the  Quotient  in  Sirups  to  be  Examined  for 

Raffinose 

After  the  value  in  Brix  degrees  for  the  sirup  in  question  has  been  found 
by  the  method  of  section  I,  the  sugar  content  in  the  same  is  found  from 
the  direct  polarization  (/>),  and  the  polarization  at  20°,  or  at  a  tempera- 
ture very  close  to  this  and  properly  corrected,  after  inversion  (/),  by  aid 
of  the  following  formula  : 

0.5124  P—I 

5(Sugar)=     0.839    • 

If  the  amount  of  raffinose  is  to  be  found  in  addition,  this  formula  is 
used  : 

R(  Raffinose)  =^-g^. 

The  inversion  is  to  be  made  in  the  manner  described  in  section  I, 
under  a. 

Example  :  For  a  sirup  showing  85.6°  Brix,  76.6^  direct  polarization  and 
—  3.0°  polarization  after  inversion  (for  the  whole  normal  weight),  the 
amount  of  sugar  is  found  as 

0.5124  x  76.6  4-  3 

0.839  50.4  per  cent., 

and  the  quotient  is  58.8. 

II.  Determination  of  the  Amount  of  Saccharose  in  Crystal  Sugar  Sup- 
posed to  Contain  Raffinose 

The  determination  of  the  saccharose  content  of  crystal  sugar  contain- 
ing raffinose  is  made  as  for  sirups  containing  raffinose,  according  to  the 
directions  in  I,  2. 

Only  such  sugars  shall  be  considered  as  containing  raffinose  in  which 
the  difference  between  the  saccharose  content  by  direct  polarization  and 


SACCHARIMETRY  483 

that  found  by  application  of  the  raffinose  formula  is  more  than  i  per  cent, 
for  sugars  of  class  a,  or  more  than  0.6  per  cent,  for  sugars  of  classes  b 
and  c,  because  smaller  differences  may  be  found  in  raffinose  free  sugars 
at  times,  and  possibly  may  be  results  of  errors  of  observation. 

With  differences  of  i  per  cent,  or  0.6  per  cent,  or  less,  in  the  two 
classes,  the  result  of  the  direct  polarization  is  to  be  taken  then  as  show- 
ing the  real  saccharose  content  of  the  sugar  tested.  If  the  polarization  is 
below  90,  a  further  test  is  unnecessary. 

In  the  statement  of  the  final  result,  fractions  below  whole  tenths  are  to 
be  dropped.  For  example,  a  sugar  content  of  97.19  is  to  be  rounded  off 
to  97.  i. 

Final  Provision 

A  written  certificate  must  be  made  out  for  each  investigation  and  filed 
with  the  office  sending  the  sample  in  question.  Besides  an  accurate 
description  of  the  sample  this  certificate  must  contain  : 

I.  In  determining  the  quotient  of  sirups  : 

1.  In  the  cases  described  under  a  at  the  beginning  : 

the  specific  gravity,  the  Brix  degrees  calculated  from  this,  the 
direct  polarization,  and  the  quotient  calculated. 

2.  In  the  cases  given  under  b  : 

the  result  of  the  test  for  invert  sugar,  the  specific  gravity, 
the  Brix  degrees  calculated  from  this,  the  direct  polarization  ; 
further,  in  case  a  quotient  below  70  is  found  from  these  data, 
either  a  statement  of  why  a  test  has  not  been  made  for  starch 
sugar,  or  the  result  of  such  a  test  with  figures  for  the  polarization 
found  after  inversion  ;  further,  with  reference  to  sirups  free  from 
starch  sugar  the  amount  of  copper  and  the  calculated  sugar  con- 
tent, and  for  sirups  containing  starch  sugar  the  amount  of  copper 
found,  the  invert  sugar  content  corresponding  to  this,  the  total 
sugar  content  (polarization  —  invert  sugar),  and  finally  the 
calculated  quotient. 

3.  In  the  cases  falling  under  c  above  : 

the  result  of  the  test  for  invert  sugar,  as  far  as  this  is  necessary, 
and  then,  in  case  the  application  of  the  raffinose  formula  is  per- 
missible, the  specific  gravity,  the  Brix  degrees  calculated  from 
this,  the  direct  polarization,  the  polarization  after  inversion,  the 
sugar  content  calculated  from  these  data  by  aid  of  the  raffinose 
formula,  and  the  quotient ;  otherwise,  the  data  given  under  2 
above. 

II.  In  determining  the  saccharose  content  of  crystal  sugar  supposed  to 

contain  raffinose  : 

in  case  the  polarization  falls  below  90,  this  only,  but  otherwise, 
in  addition  the  polarization  after  inversion,  the  sugar  content 
calculated  by  the  raffinose  formula,  and  then  the  resultant 
saccharose  in  per  cent,  as  required  by  the  regulations. 


484        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATIQ 


Appendix  E 

DIRECTIONS  °~ 

for  finding  the  amount  of  sugar  in  saccharine  products 
According  to  $3  of  the  rules  for  carrying  out  the  provisions  of  $6  of 
the  sugar  tax  law,  a  rebate  of  the  sugar  tax  for  saccharine  manufactured 
products,  except  in  the  case  of  caramels  containing  starch  sugar,  can  be 
allowed  only  when  they  are  made  without  the  use  of  honey  or  starch 
sugar.  While  the  fact  of  not  using  honey  may  be  established  by  the 
factory  control  and  the  factory  production  books,  the  absence  of  starch 
sugar  is  to  be  determined  by  chemical  tests  of  the  products  of  the  factory. 
These  investigations  are  to  be  made  according  to  the  directions  in  section 
i  of  Appendix  C  of  the  Rules  of  Procedure,  but  with  this  provision,  that 
in  saccharine  factory  products  the  presence  of  starch  sugar  is  to  be  as- 
sumed when  the  left-hand  rotation  after  inversion  of  the  solution  is  — 28 
or  less,  for  every  100  parts  found  in  the  direct  polarization. 

The  saccharose  content  of  starch  sugar-free  saccharine  factory  prod- 
ucts is  to  be  established  by  different  means,  according  as  they  contain 
less  than  2  per  cent.,  or  2  per  cent,  or  more  of  invert  sugar.  In  conse- 
quence, the  test  of  the  product  for  invert  sugar  is  to  be  made  according 
to  section  i,  of  Appendix  B,  but  with  the  variation  that  the  sugar  solu- 
tion to  be  boiled  with  the  Fehling  solution  shall  correspond,  not  to  10 
grams  of  substance,  but  to  10  per  cent,  polarization. 

Of  saccharine,  products  which  contain  less  than  2  per  cent,  of  invert 
sugar,  the  saccharose  content  will  be  found  according  to  the  Clerget 
method,  in  which  the  inversion  is  to  be  made  exactly  as  given  in  the 
directions  of  section  i  under  a  in  Appendix  C,  and  from  the  sum  of  the 
two  polarizations  (before  and  after  inversion)  the  saccharose  content  is  to 
be  found  by  the  formula 

-_  100  S 

~  142.66  —  yt  t ' 

in  which  S  is  the  amount  of  sugar,  s  the  sum  of  the  two  polarizations 
for  the  normal  weight,  and  /  the  temperature  at  which  the  polarizations 
were  made.  The  constant  (C)  142.66  assumes  the  use  of  the  half-nor- 
mal weight  ( 13.024  grams)  of  sugar  in  the  observation,  and  is  to  be  re- 
placed by  different  numbers  corresponding  to  the  amount  of  substance 
taken  for  inversion.  These  numbers  are  given  by  the  following  table  : 


For  Krains  sugar 
in  100  c  c. 

For  C  to  be 
taken. 

For  grains  sugar 
in  100  cc. 

For  Cto  be 
taken. 

I 

141.85 

II 

142.52 

2 

141.91 

12 

142.59 

3 

141.98 

13 

142.66 

4 

142.05 

14                       M2.73 

5 

142.12 

15                       142.79 

6 

142.18 

16                      142.86 

7 

142.25 

17                      142.93 

8 

142.32 

18                      M3-00 

9 

142.39 

19 

143.07 

10 

142.46 

20 

143.13 

SACCHARIMETRY 


485 


If  there  is  found,  for  example,  a  direct  polarization  of  -j-  30  in  a  200 
mm.  tube  for  a  solution  of  the  normal  weight  dissolved  to  200  cc.  ,  the 
calculated  direct  rotation  of  the  inverted  solution  containing  75  cc.  of  the 
original  must  be  —  22.5.  As  TOO  polarization  corresponds  to  26.048  grams 
of  substance,  5.86  grams,  or  rounded  off,  6  grams  of  substance  would  cor- 
respond to  the  -f>  22.5°  ;  according  to  the  table,  then,  the  constant  142.18 
is  to  be  applied.  Assuming  then,  that  a  left-hand  rotation  of  —  7.1°  is 
observed  at  20°,  this  corresponds  Tor  the  half  normal  weight  to 
—  7.1  X  IPO 

75 
As  the  direct  polarization  for  the  whole  normal  weight  is 

content  is  calculated  as  100 


—  9.47°,  and  for  the  whole  normal  weight  to  —  18.94°. 

60,  the  sugar 


—  :        =59.72   or,   rounded,  59.7  per 


cent.,  lower  fractions  than  whole  tenths  being  disregarded. 

The  sugar  content  of  such  products  as  contain  2  per  cent,  or  more  of 
invert  sugar  is  to  be  determined  by  the  copper  method  given  in  section 
i  of  Appendix  C  of  the  Rules  of  Procedure.  A  portion  of  the  sugar  solu- 
tion is  inverted  as  there  explained  and  the  amount  of  substance  to  be  em- 
ployed determined  as  in  the  case  of  finding  the  invert  sugar  in  products 
containing  starch  sugar,  and  then  the  properly  made  solution  is  boiled 
three  minutes  with  Fehling's  solution.  The  amount  of  saccharose  cor- 
responding to  the  copper  found  is  given  in  the  following  table  : 

TABLE  FOR  THE  CALCULATION  OF  CANE  SUGAR  CORRESPONDING  TO 

INVERT  SUGAR  FROM  AMOUNT  OF  REDUCED  COPPER 

AFTER  THREE  MINUTES'  BOILING 


Copper, 
mg. 

Cane- 
sugar, 
mg. 

Copper, 
mg.' 

Cane- 
sugar, 
mg. 

Copper, 
mg. 

Cane- 
sugar, 
mg. 

Copper, 
mg. 

Cane- 
sugar, 
mg. 

79 

40.0 

96 

48.3 

H3 

56.8 

130 

65.3 

80 

40.5 

97 

48.8 

114 

57-3 

131 

65-8 

8l 

41.0 

98 

49-3 

H5 

57.8 

I32 

66.3 

82 

41-5 

99 

49.8 

1  16 

58.3 

133 

66.8 

83 

42.0 

100 

50.3 

117 

58.8 

134 

67-3 

84 

42-5 

101 

50.8 

118 

59-3 

135 

67.8 

85 

42.9 

102 

51-3 

119 

59-8 

136 

68.3 

86 

434 

103 

51.8 

120 

60.2 

137 

68.8 

87 

43-9 

104 

52.3 

121 

60.7 

138 

69.4 

88 

44-4 

105 

52.8 

122 

61.2 

139 

69.9 

89 

44-9 

106 

53-3 

I23 

61.7 

140 

70.4 

90 

45-4 

107 

53-8 

124 

62.2 

141 

70.9 

9i 

45-9 

108 

54.3 

125 

62.8 

142 

71.4 

92 

46.4 

109 

54-8 

126 

63-3 

143 

71.9 

93 

46.8 

no 

55-3 

I27 

63.8 

144 

72.4 

94 

47-3 

III 

55-8 

128 

64.3 

145 

72.9 

95 

47-8 

112 

56.3 

I29 

64.8 

146 

73-4 

486        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 


Copper, 
rag. 

Cane- 
sugar, 
mg. 

Copper, 
mg. 

Cane- 
sugar, 
mg. 

Copper, 
mg. 

Cane- 
sugar, 
mg. 

Copper, 
mg. 

Cane- 
sugar, 
mg. 

147 

73-9 

I76 

88.9 

205 

104.1 

234 

II9.7 

I48 

74-5 

177 

89.4 

206 

104.6 

235 

120.3 

149 

75-0 

I78 

89.9 

207 

105.2 

236 

120.8 

150 

75-5 

179 

90.4 

208 

105-7 

237 

121.3 

151 

76.0 

180 

91.0 

209 

106.2 

238 

I2I.8 

152 

76.5 

181 

91-5 

210 

106.7  1 

239 

122.4 

153 

77.0 

182 

^2.0 

211 

107.3 

240 

122.9 

154 

77-5 

183 

92.5 

212 

107.8 

241 

123.5 

155 

78.0 

184 

93-1 

2I3 

108.4 

242 

124.0 

156 

78.5 

185 

93-6 

214 

108.9 

243 

124.6 

157 

79.0 

[86 

94-1 

215 

109.4 

244 

125.1 

158 

79.6 

187 

94.6 

216 

109.9 

245 

125.7 

159 

80.  i 

188 

95-1 

217 

110.5 

246 

126.2 

160 

80.6 

189 

95-7 

218 

III.  I 

247 

126.8 

161 

81.1 

190 

96.2 

219 

in.  6 

248 

127.3 

162 

81.6 

191 

96.7 

220 

112.  2 

249 

127.9 

163 

82.1 

192 

97-2 

221 

112.7 

250 

128.4 

164 

82.6 

193 

97-7 

222 

113.2 

251 

128.9 

165 

83.2 

194 

98.3 

223 

113-7 

252 

129.4 

166 

83.7 

195 

98.8 

224 

114.3 

253 

130.0 

167 

84.2 

196 

99-3 

225 

114.8 

254 

130.6 

168 

84.7 

197 

99-8 

226 

115-4 

255 

131.1 

169 

85-2 

198 

100.4 

227 

115.9 

256 

131.7 

170 

85.7 

199 

100.9 

228 

116.4 

257 

132.2 

171 

86.3 

200 

101.4 

229 

117.0 

258 

132.8 

172 

86.8 

201 

101.9 

230   j   II7-5 

259 

133-3 

173 

87.3 

202 

102.5 

231    118.1 

260 

133.9 

174 

87.8 

203 

103.1 

232  ;  118.6 

175 

88.3 

204 

103.6 

233  !  "9-2 

The  percentage  amount  of  saccharose  is  calculated  from  this,  and  then 
the  total  sugar  content  is  expressed  as  saccharose  and  given  in  terms  of 
per  cent,  of  the  substance. 

With  reference  to  the  preparation  of  solutions  of  the  substance  it  may 
be  remarked  that,  as  in  the  case  of  digestion  methods  of  beet  testing,  it 
is  in  general  not  allowable  to  fill  up  a  flask  with  the  solid  substance 
(chocolates,  etc.)  and  water  to  the  mark,  because  the  error  caused  by  the 
insoluble  parts  of  the  solid  would  be  too  great.  As  a  rule,  therefore,  the 
solution  is  to  be  made  up  to  a  definite  volume  only  after  filtration  and 
washing  out  of  the  residue. 

With  reference  to  the  investigation  of  saccharine  products,  on  which 
rebate  is  allowable,  the  following  details  may  be  pointed  out  : 


SACCHARIMETRY  487 

A.  Chocolates 

It  is  convenient  to  moisten  the  normal  weight  with  alcohol  to  facilitate 
the  subsequent  wetting  with  water,  and  then  to  add  about  30  cc.  of  water 
and  warm  ten  to  fifteen  minutes  on  the  water-bath.  The  liquid  is  next 
filtered  hot,  and  may  run  through  turbid  without  harm  ;  the  residue  is 
washed  with  hot  water.  After  treatment  with  about  10  cc.  of  basic  lead 
acetate  the  filtrate  is  allowed  to  stand  a  quarter  of  an  hour,  then  clarified 
with  alum  and  a  few  drops  of  alumina  cream,  and  finally  made  up  to  a 
proper  volume,  about  200  cc. 

B.  Confectioner's  Wares 

a.  Caramels  (bonbons,  boltjes}  with  exception  of  gum  drops,  which  are 

not  rebatable 

With  regard  to  such  caramels  as  are  declared  by  the  manufacturer  to 
contain  starch  sugar,  it  must  be  determined  by  tests  that  they  show  at 
least  80°  of  -f  rotation  and  50  per  cent,  of  saccharose  by  the  Clerget  pro- 
cess. Otherwise  they  must  be  considered  as  not  entitled  to  rebate. 

Caramels  which  are  declared  as  free  from  starch  sugar,  must  be  tested 
foiS  this.  If  no  starch  sugar  is  found  the  further  investigation  is  made  as 
with  white  sugar  candies. 

b.  Dragees  (sugar-coated  seeds  and  nuts  with  addition  of  flour} 
Dragees  are  extracted  as  are  chocolates.     They  nearly  always  contain 
invert  sugar. 

c.  White  sugar  candies  (sugar  with  addition  of  ethereal  oils  or  coloring- 

matter} 

The  solid  residue  may  be  neglected.  The  normal  weight  is,  therefore, 
filled  directly  into  a  100  cc.  flask,  water  added  to  the  mark  after  solution, 
and  the  filtration  performed  afterwards. 

d.  Porous  products  (mixtures  of  sugar  with  some  binding  substance  as 

white  of  egg,  with  addition  of  a  flavor  or  remedial  agent} 
The  usually  very  small  amount  of  binding  material  (white  of  egg,  gela- 
tin, gumarabic,  tragacanth  or  glue)  is  to  be  removed  by  basic  lead  acetate 
or  alumina. 

The  santonin  lozenges,  which  are  classed  among  the  porous  products, 
contain  sodium  santoninate.  The  addition  of  basic  lead  acetate  is  neces- 
sary to  remove  the  santoninic  acid. 

e.  Dessert  bonbons  (creams,  etc,,   made  of  sugar  and  enclosed  fruits  or 

marmalade,  etc. } 

The  sample  is  dissolved  in  water.  If  but  little  residue  remains  it  may 
be  made  up  to  the  mark  directly  ;  otherwise  it  is  necessary  to  filter  first. 

/.  Marchpane  mass  and  marchpane  cakes  (sugar  with  crushed  almonds} 
The  material  is  conveniently  rubbed  up  with  cold  water  in  a  porcelain 
dish  and  clarified  before  filtration  with  much  alumina  cream.     As  a  rule 
marchpane  is  free  from  invert  sugar. 


488        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

g.  Cakes  and  similar  bakers'1  wares 

The  sugar  is  extracted  with  alcohol  of  85  to  90  per  cent.  After  evap- 
oration of  the  alcohol  the  filtrate  is  tested. 

h.  Sugar-coated  tropical  or  native  fruits \  glace  or  candied  ;  fruits  pre- 
served in  sugar  solutions  (marmalades,  pastes,  compotes,  jellies} 
If  the  material  is  solid,  special  pains  must  be  taken  in  the  preparation 
of  an  averge  sample  of  homogeneous  composition  ;  as  for  example,  by 
warming  and  stirring.     The  sugar  is  extracted  as  for  g  above.     As  a  rule, 
invert  sugar  is  present. 

C.  Alcoholic  Liquors  Containing  Sugar 

The  alcohol  does  not  interfere  with  the  direct  polarization  ;  but  it  must 
be  evaporated  before  the  inversion  polarization. 

D.  Liquid  Refined  Sugar 

Liquid  refined  sugar  contains  invert  sugar  as  a  rule.  The  test  may  be 
limited  to  determining  that  there  is  a  total  sugar  content  of  at  least  75 
per  cent. 

Final  Provision 

A  written  certificate  fur  each  investigation  must  be  handed  to  the  office 
which  submitted  the  sample,  and  this  must  contain,  besides  an  exact 
description  of  the  sample,  data  on  the  methods  and  results  of  the  tests 
carried  out,  and  the  percentage  amount  of  sugar  calculated  from  them. 

II.  Determination  of  Milk- Sugar 

178.  The     specific     rotation     of     crystallized    milk-sugar, 
C12HWOU  -f-  H2O,  was  found  by  Schmoeger1   for  solutions  con- 
taining from  o  to  36  per  cent,  to  be,  at  20°, 
[or]}?  =  52.53  constant. 

Exactly  the  same  value  was  fotmd  by  Parcus  and  Tollens* 
at  20°  for  solutions  having  a  concentration  of  4.8  to  7.1  grams 
in  100  cc.  Schmoeger  found  also  that  in  the  neighborhood  of 
20°  the  above  value  of  the  specific  rotation  is  decreased  0.075 
for  each  degree  of  increase  in  temperature. 

As  already  shown  in  §72,  crystallized  milk-sugar  exhibits 
birotation  immediately  after  solution  which,  however,  may  be 
rapidly  changed  to  the  constant  rotation  by  heating  to  100°. 
On  the  other  hand,  the  sugar  dehydrated  at  100°  exhibits, 
after  solution  in  cold  water,  at  the  outset  a  lower  rotation  than 
the  normal.  This  is  easily  changed  also  to  the  normal  rotation 
by  heating. 

1  Her.  d.  chem.  Ges.,  13,  1922  (1880). 

5  Parcus  and  Tollens  :  Ann.  Chem.  (l,iebig),  357,  160  (1890). 


DETERMINATION   OF   MILK-SUGAR  489 

For  the  determination  of  milk-sugar  with  instruments  gradu- 
ated in  angular  degrees  we  have 


therefore  : 

a 
*-=  *  -9037  -y, 

and  by  use  of  a  200  mm.  tube,  with  sodium  light,  at  20°, 

c  =  0.9518  a, 
or  with  the  use  of  a  tube  190.37  mm.  in  length, 

c  =  of. 

If  the  problem  is  to  test  a  substance  as  to  its  content  of  milk- 
sugar  in  an  instrument  with  the  Ventzke  scale,  it  is  best  to  dis- 
solve that  weight  in  a  100  cc.  flask,  which,  if  it  were  pure 
milk-sugar,  would  polarize  100°.  This  weight  is  found  from 
the  proportion  : 

x  :  26.048  :  :  66.50  :  52.72* 

^  =  32.856. 

By  taking  32.856  grams  of  substance,  each  degree  would 
then  correspond  to  i  per  cent,  of  milk-sugar.  If  a  solution  is 
to  be  examined  and  it  is  required  to  find  the  concentration  of 
the  milk-sugar  in  it,  it  is  to  be  observed  that  a  polarization  of 
i°  V.  corresponds  to  a  concentration  of  0.32856  gram  of  milk- 
sugar  in  loo  Mohr  units  of  volume  at  17.5°.  Using  a  200 
mm.  tube, 

c  =  0.32856  Pol. 

Exactly  the  same  value  is  reached  from  the  basis  of  the 
observation2  that  one  Ventzke  degree  for  milk-sugar  is  equal 
to  0.3452  circular  degrees,  with  sodium  light.  As  c  =  0.9518  <*, 
we  have  also 

c  —  o-QS1^  X  0.3452  Pol, 
or 

c  =  0.32856  Pol. 

179.  The  Determination  of  Sugar  in  Milk  is  carried  out,  accord- 
ing to  Schmoeger,3  in  this  way  : 

1  This  is  the  specific  rotation  of  milk-sugar  at  17.5°. 

-  I^andolt  :  "  Ueber  polarimetrisch-cheraische  Analyse,"  Ber.  d.  chem.  Ges.,  ai, 
191  (1888). 

:  Ber.  d.  milchwirthschaftl.  Instituts  zu  Proskau,  1883-4. 


490         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

1.  According  to  Hoppe-Seyler,  50  cc.  of  milk  is  boiled  with 
25  cc.  of  a  20  to  25  per  cent,  lead  acetate  solution,  to  the  still 
warm  liquid,  5  cc.  of  a  10  per  cent,  alum  solution  is  added,  and 
then  the  mixture  is  cooled,   filled  up  to   100  cc.  and  filtered. 
The  volume  of  the  precipitate  is  in  the  mean  3  cc. ,  and  is  to 
be  taken  into  consideration. 

2.  100  cc.  of  milk  is  coagulated  by  addition  of  6  cc.  of  10  to  15 
per  cent,  acetic  acid  and  after  standing  half  an  hour  is  filtered. 
A  slight  turbidity  from  fat  globules  does  no  harm.     50  cc.  of 
the  filtrate  is  heated  to  boiling  with  3  to  4  cc.   of  basic  lead 
acetate  solution  (sp.  gr.  1.2),  and,  after  cooling,  water  is  added 
to  make  up  for  loss  on  evaporation.     The  liquid  is  then  filtered. 

3.  100  cc.  of  milk  is  coagulated  as  before  or  by   addition  of 
6  cc.  of  10  to  15  per  cent,  sulphuric  acid,   but  instead  of  sepa- 
rating the  proteids  by  basic  lead  acetate,   50  cc.  of  the  filtrate 
is  treated  in  the  cold  with  5  cc.  of  commercial  phosphotungstic 
acid,  then  filtered  and  polarized.     The  result  must  be  multi- 
plied by  i.i. 

As  in  methods  2  and  3,  the  volume  of  the  precipitate  is 
taken  as 6  cc.,  in  the  mean  ;  it  is  advisable  to  add  just  6  cc.  of 
acid  for  coagulation,  because  then  the  concentration  of  the 
milk-sugar  in  the  filtrate  (whey)  will  be  exactly  the  same 
as  in  the  original  milk.  Besides,  in  methods  2  and  3,  the  dis- 
advantageous dilution  of  the  liquid  containing  the  milk-sugar 
to  the  double  volume  is  avoided. 

A  comparison  of  the  three  processes  led  to  the  conclusion 
that  method  3  gives  about  0.15  per  cent,  higher  values  than 
method  2,  and  that  this  in  turn  gives  again  0.15  per  cent, 
higher  results  than  method  i .  Schmoeger  traces  {hese  differ- 
ences to  this,  that  in  mixing  the  milk  with  the  lead  solution, 
milk-sugar,  or  possibly  some  other  right-rotating  substance 
not  clearly  known,  is  thrown  out  of  solution.  This  is  certainly 
the  case  when,  after  using  an  exce'ss  of  lead  solution,  the  fil- 
trate is  alkaline.  Schmoeger  is,  therefore,  of  the  opinion  that 
the  third  method  gives  correct  results,  possibly  a  few  hun- 
dredths  too  high. 

But,  on  the  other  hand,  the  results  obtained  by  method  i 
agree  very  closely  with  the  gravimetric  analyses  according  to 
Tollens,  and  those  by  method  2  with  the  gravimetric  analyses 


DETERMINATION   OF   DEXTROSE  49* 

according  to  Soxhlet  with  fair  accuracy.  It  is  not  possible, 
therefore,  to  give  a  final  decision  as  to  which  is  the  more  accu- 
rate procedure.  An  advantage  in  the  polarimetric  method 
over  the  gravimetric  is  found  in  the  greater  rapidity  and  con- 
venience with  which  it  may  be  carried  out. 

III.  Determination  of  Glucose  (Dextrose,  Grape-Sugar)  (Crystal- 
lized C6H1206  +  H20) 

180.  Tollens1  has  given  this  formula  showing  the  dependence 
of  the  specific  rotation  of  dextrose  anhydride  on  the  per- 
centage strength  of  the  solution  : 

\_a]™  =  52.50  -f  0.0188 p  -f  0.000517 /'-'. 
From  this  we  have  for  : 


P  =   5 

10 

15 

20 

25 

30 

[or]  =52.61 

52.74 

52.90 

53.08 

53-29 

53-53 

/==  35 

40 

45 

50 

55 

60 

[«]  =53-79 

54.o8 

54-39 

54-73 

55-10 

55-49 

The  specific  rotation  increases  then  appreciably  with  the 
concentration.  But  for  solutions  up  to  15  per  cent,  strength, 
without  very  great  error,  [«]  can  be  taken  as  equal  to  52.80.  If 

we  substitute  this  value  in  the  equation  [or]  =  ,  this  for- 

mula follows  for  calculating  the  percentage  strength  from  the 
observed  angle  a, 

/=  1-894  7^, 

and  using  a  2  dm.  tube, 

(0  ^  =  0.947-^-- 

If  not  the  percentage  strength  but  the  concentration  of  the  solu- 
tion is  to  be  found,  that  is,  the  number  of  grams  of  sugar  in  100 
cc.  of  solution,  then  this  formula  may  be  transformed  into 
the  simpler  one, 

(2)  c  =  0.947  a- 

The  error  made  by  neglecting  the  variation  of  the  specific 
rotation  with  the  strength  of  solution  reaches  then  in  the  most 
unfavorable  case  0.03  per  cent.,  assuming  that  the  observed 
angle  of  rotation  a  is  measured  at  20°  with  use  of  sodium 
light. 

1  Tollens  :  Ber.  d.  chem.  Ges.,  17,  2238  (1884). 


492        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

For  greater  concentrations  (15  to  50  per  cent.)  Landolt1  has 
calculated  the  following  formula,   for  finding  the  percentage 
strength,  from  the  observations  of  Tollens  : 
(3)  p  =  0.948  a  —  0.0032  of'2, 

where  a  is  the  rotation  for  a  2  dm.  tube. 

Dextrose  may  be  determined  by  use  of  the  Ventzke  sac- 
charimeter  also,  since,  according  to  the  observations  of  Hoppe- 
Seyler,*  its  rotation  dispersion  is  very  nearly  the  same  as  that 
of  quartz.  It  has  been  found  by  direct  experiments3  that  for 
dextrose,  i°  V.  =  0.3448  ±  0.0008  circular  degrees  (Na  light). 
If  we  represent  by  Pol.  the  number  of  Ventzke  degrees  read 
off  for  a  2  dm.  tube  at  20°,  the  formulas  just  developed  may 
be  transformed  into  these  : 


(I)  p  =  0.3265  -~  O  =  o  to  15] 

(II)  c=  0.3265  Pol  [r=otoi6] 
III)    p  =  0.3269  Pol  —  o.ooo  381  Pol2  lp  =  o  to  50] 

Thus,  for  example,  a  grape-sugar  solution  which  shows  a 
rotation  of  34.48°  in  an  instrument  with  circular  degrees  must 
polarize  exactly  100  in  the  Ventzke  saccharimeter.  We  have 
by  Formula  (3), 

p  =  0.948  X  34.48  —  0.0032  X  34.48'  =  28.88  per  cent., 
and  likewise  by  Formula  (III), 

p  =  0.3269  X  loo  —  0.000381  X  loo2  =  28.88  per  cent. 
But,  nevertheless,  one  cannot  expect  as  accurate  results 
from  the  saccharimeter  as  from  the  instrument  with  circular 
degrees,  because  the  value  of  a  circular  degree  in  saccharimeter 
degrees  might  not  be  the  same  for  all  instruments  and  all  solu- 
tions. 

For  this  reason,  and  because  the  specific  rotation  of  dextrose 
is  dependent  on  the  temperature  and  concentration,  a  normal 
weight  cannot  be  definitely  fixed,  which  may  be  dissolved  to 
make  100  Mohr  cc.  and  give  directly,  in  the  saccharimeter, 
the  percentage  strength  of  dextrose  in  the  dissolved  substance. 
But,  however,  for  most  practical  needs,  sufficiently  accurate 
values  may  be  derived  from  the  following  considerations  : 

1  I^andolt  :  Her.  d.  chem.  Ges.,  ai,  199  (1888). 
-  See  I,andolt  :  Ibid.,  ai,  194  (1888). 
/tschr.  anal.  Chem.,  5,  413  (1866). 


DETERMINATION   OF   DEXTROSE  493 

For  dilute  solutions  we  have  above, 

c  =  0.3265  X/W, 


Accordingly,  a  liquid  which  contains  32.65  grams  of  dextrose 
in  100  cc.  must  be  able  to  polarize  100°  V.  But  as  the  Mohr 
unit  of  volume  is  related  to  the  cubic  centimeter  as 
1.00234  :  i,  then  to  secure  the  same  concentration  in  a  Mohr 
100  cc.  flask  there  must  be  weighed  out,  in  vacuo,  32.65  X 
1.00234  =  32.73  grams  of  the  substance  containing  dextrose 
or  32.71  grams  in  air  with  brass  weights. 

Also,  we  obtain  the  normal  weight  of  dextrose,  -/V,  when 
we  multiply  the  normal  weight  of  saccharose,  26.048,  by  the 
relation  of  their  specific  rotations.  We  obtain  in  this  way  : 

For  5  per  cent,  solutions  :  ^V=  26.048  X  —  -  —  32.91  grams. 
For  15  per  cent,  solutions  :  N  =  26.048  X  —  —  32-75  grams. 
For  25  per  cent,  solutions  :  N  =  26.048  X  —  —  =  32.50  grams. 

The  normal  weight  varies,  therefore,  for  solutions  practically 
the  most  used,  containing  o  to  25  per  cent,  of  dextrose,  be- 
tween 32.9  and  32.5  grams.  In  weighing  out  a  dextrose  sub- 
stance then,  one  must  take  into  consideration  whether  it  con- 
tains much  or  little  of  the  sugar.  The  normal  weight  derived 
above  for  dilute  solutions,  32.71  grams,  would  hold,  accord- 
ing to  the  last  calculation,  for  solutions  containing  from  17  to 
1  8  per  cent,  of  dextrose. 

If  the  amount  of  dextrose  hydrate,  instead  of  that  of  the 
anhydride,  is  desired  the  result  must  be  multiplied  by  the  re- 

lation of  the  two  molecular  weights       —  =  i  .  i  . 

1  80 

Finally,  it  must  be  remembered  that  solid  dextrose  dissolved 
in  water  exhibits  birotation,  which  is  destroyed  by  allowing 
the  solution  to  stand  twenty-four  hours,  or  by  warming. 

181.  The  Determination  of  Dextrose  in  Diabetic  Urine  may  be  ad- 
vantageously made  when  the  amount  present  is  more  than 
about  0.2  gram  in  100  cc.  With  smaller  amounts,  or  where 
the  greatest  accuracy  is  desired,  as  in  normal  urines  or  in  phys- 


494          PRACTICAL  APPLICATION  OF  OPTICAL  ROTATION 

iological  investigations,  the  chemical  methods  of  determination 
yield  more  reliable  results.  It  must  first  be  seen  whether  or 
not  the  color  of  the  urine  will  permit  a  direct  polarization, 
using  if  necessary,  a  tube  only  100  mm.  long,  or  after  diluting 
to  the  double  volume.  If  the  urine  is  not  perfectly  clear  it 
should  be  filtered  as  quickly  as  possible  through  soft  filter- 
paper.  If  the  urine  is  too  dark,  icocc.  should  be  precipitated 
by  10  cc.  of  basic  lead  acetate  solution,  and  the  filtrate  tested, 
or  it  may  be  shaken  in  a  flask  with  some  blood-charcoal  and 
then  filtered.  In  the  first  case,  the  result  of  the  polarization 
must  be  multiplied  by  i.i  on  account  of  the  dilution.  But  in 
both  cases,  a  part  of  the  grape-sugar  may  be  removed  from  the 
urine  ;  at  least  this  has  been  shown  after  application  of  basic 
lead  acetate,  and  it  may  be  assumed  for  the  charcoal  from  the 
experience  gathered  in  the  clarification  of  dark  sugar  sirups. 
These  errors  may  be  eliminated  by  making  a  parallel  experi- 
ment with  like  quantities  of  clarification  agents  and  normal 
urines  whose  sugar  content  is  brought  to  that  of  the  urine 
under  investigation,  and  which  is  polarized  before  and  after 
application  of  the  clearing  agent. 

If  the  diabetic  urine  contains  albuminous  substances  they 
may,  on  account  of  their  left  rotation,  make  the  sugar  content 
appear  much  too  low,  and  it  is,  therefore,  necessary  to  remove 
them.  loo  cc.  of  urine  is  heated  in  a  dish  to  boiling  and  then 
enough  dilute  acetic  acid  is  added  to  give  an  acid  reaction  and 
throw  down  the  albumin  as  a  flocculent  precipitate.  Then 
the  liquid  is  filtered,  the  filter  washed,  and  the  filtrate  made  up 
to  100  cc.  Or  a  measured  volume  of  urine  is  acidified  with 
acetic  acid  and  then  enough  concentrated  sodium  sulphate 
solution  added  to  bring  the  volume  to  double  the  original.  If 
the  liquid  is  now  heated,  the  albumin  separates  completely  and 
may  be  filtered  off. 

Bile  acids,  which  have  a  right-hand  rotation,  are  not  present 
in  urine  in  amount  sufficient  to  cause  an  error  in  the  above 
process. 

The  fact  that  the  albumin  in  urine  rotates  the  plane  of  polari- 
zation to  the  left  very  nearly  as  much  as  grape-sugar  does  to 
the  right,  furnishes  us  with  a  very  convenient  means  of  deter- 
mining the  amount  of  albumin  in  urine  polarimetrically.  If 


DETERMINATION   OF   MALTOSE  495 

the  polarization  of  the  urine  be  observed  at  the  same  tempera- 
ture (17.5°)  before  and  after  precipitation  of  the  albumin,  and 
at  the  same  degree  of  concentration,  we  obtain  from  the  dif- 
ference, D,  of  the  two  readings,  with  a  2  dm.  tube,  the 
amount  of  albumin,  Al,  in  the  liquid,  from  the  formula  de- 
rived above  for  the  determination  of  the  grape-sugar  content 
of  dilute  solutions  : 

Al  =  0.947  D. 

The  firm  of  Schmidt  and  Haensch  makes  a  half-shadow  in- 
strument with  circular  degrees  on  the  Laurent  system  ( §  1 1 1  to 
§113)  for  urine  analysis.  A  sodium  flame  serves  for  illumina- 
tion. In  order  to  avoid  the  necessity  of  calculating  the  sugar  or 
albumin  content  from  the  rotation  read  off  in  circular  degrees, 
according  to  the  above  equation,  tubes  of  188.6  and  94.3  mm.  in 
length  (better  189.4  and  94.7)  are  furnished  with  the  instru- 
ment, the  shorter  one  for  dark  liquids,  which  lengths  are  so 
chosen  that  i°  or  2°  of  polarization  corresponds  exactly  to  i 
gram  of  grape-sugar  in  100  cc.  of  the  liquid  analyzed. 

The  same  firm  makes  also  half-shadow  instruments  with 
wedge-compensation  for  urine  analysis,  permitting  the  use  of 
white  light  (§i33~§i34),  the  scale  of  which  is  so  arranged  that 
by  employing  a  2  dm.  tube,  the  amount  of  grape-sugar  in  100 
cc.  may  be  read  off  directly.  The  vernier  reads  to  llw  per  cent. 

IV.  Determination  of  Maltose 

(Crystallized  C12H22On  -f  H2O.     Right-rotating) 
182.  Meissl1  gives  the  following  formula  for  the  dependence 
of  the  specific  rotation  on  the  percentage  strength  and  the  tem- 
perature /. 

[a\lD  ==  140.37  —0.0184 p  —  0.095  *, 

which  holds  good  for/  =  5  to  35  and  t  —  15°  to  35°.  We 
have  from  this,  when  t=  20°,  for 

p=      5  10  15  20  25  30  35 

[a]  *°  =  138. 38      138.29      138.20      138.11      138.02      137.92      137.82 

Parcus  and  Tollens2  found  a  somewhat  lower  value  for  the 
specific  rotation  from  a  concentration  of  10  grams  in  100  cc.  at 
20°, 

MS  =  I36.85  to  136.96, 

1  J.  prakt.  Chem.,  [2]  25,  114  (1882). 

-  Parcus  and  Tollen  :  Ann.  Chem.  (I^iebig),  357,  160  (1890). 


496        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

while  for  this  concentration  the  specific  rotation  according  to 
Meissl  is  138.3. 

For  the  practical  determination  of  maltose  by  the  optical 
method  a  mean  value  of 

[«]*=  137-5 
may  be  considered  as  sufficiently  exact.     Then  at  20°, 

100  Cf 

I37'5  ~=  7x7' 

a 
c=  0.7273—, 

and  by  the  use  of  a  2  dm.  tube  at  20°, 

c  =  0.3636  tf. 
Meissl  gives  this  formula  for  the  temperature  of  17.5°  : 

c  =  0.362  a. 

As  freshly  prepared  solutions  show  a  rotation  which  is  too 
low,  they  must  be  warmed  before  polarization  or  allowed  to 
stand  some  hours. 

V.  Determination  of  Galactose 
(C6H12O6.     Right-rotating.) 

183.  According  to  Meissl1  the  change  in  the  specific  rotation 
with  the  percentage  strength  and  the  temperature  is  given  by 
the  formula, 

M/>=  83-88  +  0.0785  p  —  0.209  /, 
in  which  p  —  5  to  35  per  cent.,  /  =  10  to  30°. 
According  to  Rindell,2 

[or]',,  =  83.04  -f-  o.iggp  —  (0.276  —  0.0025 /)/, 
for  p  =  12  to  20  per  cent.,  t  =  4°  to  40°. 
If  we  take  /  =  20°,  we  have  then  for 

P-  5  10  15  20  25  30          35 

Meissl          80.10  80.49      So-88      81.27      81.66      82.06     82.45 

Rindell  80.01      81.25      82-5Q 

,  ~  .       f  80  7         81  7 

•S  Kent  and  Tolled     {  gj 

Parcus  and  Tollens4     80.33 

1  J.  prakt.  Chem.,  [2],  aa,  97  (1880). 

8  Rindell :  Ztschr.  Riibenzucker-Ind.,  30,  163  (1880). 

*/*«*.,  35,  36  (1885). 

4  Parcus  and  Tollens:  Ann.  Chem.  (I^iebig),  357,  160  (1890). 


DETERMINATION    OF   CAMPHOR  497 

For  solutions  with  o  to  1 5  per  cent. ,  and  possibly  even  to  20 
percent.,  we  may  take,  therefore,  the  Meissl  value  of  80.88 
forp=  15  as  the  mean  specific  rotation  of  galactose  at  20°. 
From  this  there  follows  : 

c  =  1.236-^-,. 
and  for  a  2  dm.  tube  at  20°, 

c  =  0.618  of. 

Freshly  dissolved  galactose  also  exhibits  birotation,  which 
at  the  ordinary  temperature  reverts  to  the  normal  rotation  after 
a  lapse  of  six  hours. 

VI.  Determination  of  Camphor,  CioHj60 

184.  The  easy  determination  of  camphor  in  the  optical  way 
has  become  of  greater  importance  since  the  introduction  of 
articles  made  of  celluloid,  a  mixture  of  nitrocellulose  and  cam- 
phor. According  to  Foerster1  the  determination  of  camphor 
in  celluloid  is  made  best  as  follows  : 

About  10  grams  of  celluloid,  containing  2  to  3  grams  of 
camphor,  is  saponified  with  four  times  its  weight  of  10  per 
cent,  sodium  hydroxide  solution  until  all  has  dissolved,  and 
the  mixture  is  then  diluted  to  250  cc.  Of  this,  120  to  150  cc. 
is  distilled  off,  the  camphor,  in  vapor,  passing  over  completely 
with  the  steam.  To  the  distillate,  collected  in  a  graduated 
receiver,  25  to  30  cc.  of  benzene  is  added  and  the  mixture  well 
shaken  ;  the  volume  of  the  benzene,  which  dissolves  the  cam- 
phor, is  read  off  and  a  part  is  then  taken  for  polarization  at  20°. 

The  author  carried  out  special  tests  to  determine  the  rota- 
tion of  camphor  in  benzene,  and  as  a  standard  he  used  pure 
camphor  with  melting-point  at  178.7°,  which  had  been  re- 
crystallized  several  times  from  50  per  cent,  alcohol.  Solutions 
up  to  the  concentration  of  40  grams  of  camphor  in  100  cc. 
(d  M/4)  were  tested  at  20°  and  with  sodium  light.  The  specific 
rotation  ar-  dependent  on  the  concentration  may  be  expressed 
by  this  formula  : 

(I)  M"  =  39-755  +  0.1725'. 

From  this  the  concentration  c  may  be  calculated  as  a  function 
of  the  angle  of  rotation  a  \ 

1  Ber.  d.  chem.  Ges.,  23,  2981  (1890). 
32 


498         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 


(II)  -  1  15.205  £   -  I  +  ^/  !  _|_  0.04367  " 

From  the  observations  themselves,   the   following  direct  re- 
lation between  concentration  and  rotation  may  be  derived  : 

(III)  c  ==  2.4683  -     —  0.01747    -"- 


This  formula  was  calculated  from  the  earlier  determinations 
of  Landolt,1  showing  the  specific  rotation  of  camphor  in  ben- 
zene, 

[«]"=  39-  19  +  0.  17084  r, 

and  from  experiments  by  Rimbach,2  the  following  for  concen- 
trations between  10  grams  and  53  grams  : 

[a]}?  =  40.21  +  o.  1309*:  -f-  0.000269  r'. 

These  two  formulas  agree  closely  with  that  of  Foerster. 
Test  experiments  showed  that  from  99  to  99.3  per  cent,  of  the 
camphor  taken  could  be  found,  which,  considering  the  method 
of  separation  used,  is  a  satisfactory  result. 

In  fats  and  oils  also,  camphor  may  be  determined  by  the 
optical  process.  According  to  Foerster  it  is  best,  in  such  cases, 
to  first  distil  the  camphor  from  the  substance  under  investi- 
gation by  aid  of  a  current  of  steam.  When  about  250  cc.  of 
distillate  has  been  collected  in  the  receiver,  this  is  then  used 
as  the  distillation  flask  and  the  rest  of  the  operation  is  carried 
out  as  with  celluloid. 

If,  in  place  of  benzene,  alcohol  is  chosen  as  the  solvent  for 
the  camphor,  the  concentration  of  the  solution  may  be  found 
by  the  following  formulas,  according  to  Landolt  ::{ 


c  =  2.3614  --  —  0.01158 
or 


-  177.53  +^/  31516.45  +  845.74^-  • 

These  obtain  for  concentrations  between  o  and  50  grams  in 
loo  cc.,  and  for  a  temperature  of  20°. 

VII.  Determination  of  Cinchona  Alkaloids 
185.  The  specific  rotation  of  the  cinchona  alkaloids  and  their 

1  I«andolt  :  Ann.  Chem.  (Uebig),  i89,  334  (1877). 

-  Kimhach  :  Ztschr.  phys.  Chem.,  9,  698  (1892). 

*  I^andolt  :  Her.  d.  chem.  r.es.,  ai,  204  (1888). 


DETERMINATION  OF  CINCHONA  ALKALOIDS  499 

most  important  salts  has  frequently  been  the  subject  of  ex- 
tended investigations  ;  numerous  observations  have  been  made 
especially  by  Hesse,1  Oudemans,2  and  Lenz,3  by  which  the  con- 
stants of  rotation  for  quinine,  hydroquinine,  cinchonine,  quini- 
dine,  and  cinchonidine  have  been  determined  with  such  accu- 
racy that  they  may  be  used  in  testing  other  preparations  as  to 
their  purity,  or  in  finding  the  composition  of  mixtures. 

With  all  these  alkaloids,  the  specific  rotation  varies  in 
marked  degree  with  the  nature  of  the  solvent,  and  moreover 
it  is  smaller,  the  greater  the  concentration  and  the  higher  the 
temperature.  Hesse  measured  the  rotation  of  solutions  which 
contained  from  i  to  10  grams  of  substance  in  100  cc.,  accord- 
ing to  the  degree  of  solubility.  As  solvents,  alcohol  of  97 
volume  per  cent,  was  used  for  the  pure  alkaloids,  and  either 
pure  water  or  dilute  hydrochloric  or  sulphuric  acid  of  known 
strength  for  the  salts.  L,enz  employed  as  a  solvent  a  mixture 
of  2  volumes  of  chloroform  and  i  volume  of  97  per  cent, 
alcohol,  and  determined  the  specific  rotation  in  solutions  of  i 
to  3  per  cent,  strength. 

Notwithstanding  these  fundamental  investigations,  no 
method  is  yet  known  by  which  the  alkaloids  in  extracts  of 
cinchona  bark  or  in  the  quinine  of  commerce  may  be  found  by 
the  optical  process.  This  is  due  partly  to  the  fact,  already  re- 
ferred to,  that  the  specific  rotation  is  in  a  large  measure  de- 
pendent on  the  external  conditions  under  which  the  solutions 
in  question  must  be  tested,  and  partly  to  this,  that  the  optical 
analysis  of  a  mixture  of  several  active  substances  cannot,  in 
general,  be  made  with  accuracy,  and  even  when  only  two  or 
three  are  in  solution,  while  in  any  case  the  qualitative  compo- 
sition of  the  mixture  must  be  known,  which  can  be  determined 
only  by  the  methods  of  chemical  analysis.  Finally,  this  diffi- 
culty is  met  with  in  the  optical  determination  of  the  alkaloids 
in  the  extracts  from  cinchona  bark,  that  these  extracts  contain 
a  yellow  coloring-matter  which  cannot  be  separated  alone,  and 
the  presence  of  which  makes  the  observation  in  the  polarimeter 
uncertain. 

1  Hesse  :  Ann.  Chem.  (I,iebig),  176,  203  ;  182,  128. 

2  Oudemans  :  Ibid.,  182,  33. 

3  I,enz  :  Ztschr.  anal.  Chem.,  37,  549  (1888). 


500        PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

In  such  investigations,  therefore,  it  is  customary  to  effect 
the  extraction  and  separation  of  the  alkaloids  by  chemical 
methods,  and  then  to  resort  to  the  optical  observations  to  con- 
trol the  results  of  the  chemical  analysis  or  to  test  the  separated 
alkaloids  as  to  their  purity. 

For  the  determination  of  the  quantitative  composition  of  a 
mixture  of  alkaloids,  the  specific  rotation  may  be  employed  in 
all  those  cases  where  the  analysis  of  a  mixture  of  two  known 
alkaloids  only  is  involved.  The  following  conditions  then 
obtain  : 

Of  the  mixture  of  two  alkaloids,  c  grams  is  weighed  off, 
dissolved  to  make  100  cc. ,  and  then  the  angle  of  rotation,  ay 
is  found  in  a  tube  of  /  dm.  length,  from  which  may  be  cal- 
culated the  specific  rotation  of  the  mixture,  a  =  - .  If  the 

i  /\  c 

mixture  contains  x  per  cent,  of  one  alkaloid,  whose  specific 
rotation  is  [<*]»>  andjy  —  100  —  x  per  cent,  of  the  other  con- 
stituent with  the  specific  rotation  [tf]v,  then 

*X  OL+  (100  —  x)  [«L=  100  [«] 
and  consequently, 

[«]  -  Mv 

X  =  100  ~f-4 f-1— 

,[«]*— I>L 
O]r-  M 

y  —  loo  ~-\ =-*• . 

ixu-  01 

In  this  way,  it  is  possible  to  analyze  mixtures  of  any  active 
substances,  provided  the  specific  rotations  of  the  pure  sub- 
stances are  known  and  are  not  subject  to  too  great  variations 
within  the  limits  of  the  concentrations  employed.1  But,  in  any 
event,  it  is  advisable  to  take  the  concentration  of  the  mixture 
only  as  great  as  appears  necessary  for  the  accurate  calculation 
of  the  specific  rotation. 

Hesse2  has  already  employed  this  general  method  to  deter- 
mine the  amount  of  cinchonidine  sulphate  in  the  commercial 
quinine  sulphate,  nearly  free  from  other  alkaloids. 

He  proceeded  in  this  way,  by  taking  first,  of  the  sulphate  in 
question,  an  amount  corresponding  to  2  grams  of  the  anhydrous 
salt,  dissolving  in  a  25  cc.  flask  in  10  cc.  of  normal  hydro- 

1  See  Hesse  :   Ann.  Chem.  (Uebij?),  i8»,  146  and  152  ;  Oudemans  :  Ibid.,  i8a,  63,  65. 
•  Hesse  :  Ibid.,  205,  217  (1880). 


C^^fflC 


DETERMINATION   OF   COCAINE  5OI 


acid,  and  filling  to  the  mark  with  water  at  15°  C. 
After  complete  solution  and  mixing,  the  liquid  was  filtered 
into  a  220  mm.  jacketed  tube  and  polarized  at  15°  in  a  Wild 
polaristrobometer.  If  a  represents  the  angle  of  rotation  of  the 
anhydrous  quinine  sulphate  under  these  conditions  (a  = 
40.309°  was  found),  and  ft  the  rotation  of  the  anhydrous  cin- 
chonidine  sulphate  (ft  =  -26.598°  was  observed),  and  y, 
finally,  the  angle  of  rotation  of  the  mixture  taken  for  the 
analysis,  then  the  amount  of  cinchonidine  sulphate,  y,  in  the 
unit  of  weight  of  the  mixture  is  given  by 

i  =  a  —  y^    -40.309  —  y 

a  —  ft  -13.711 

while  the  amount  of  the  quinine  sulphate  is 
^Y  —  <*  _Y  +  26.598 

X  —  u  * 

a  —  ft        —13.711 

VIII.  Determination  of  Cocaine 

186.  The  specific  rotation  of  cocaine,  C,.H21NO4,  in  chloro- 
form, and  of  the  hydrochloride,  C17H21NO4.HC1,  in  a  mixture 
of  60  parts  of  absolute  alcohol  and  90  parts  of  water,  has  been 
determined  by  O.  Antrick.1  He  found  for  a  preparation  of  the 
base  of  the  greatest  possible  purity  : 

[«]"  =     -  15-827  —  0.00585  q, 
or, 

[or]  £  =    —  16.412  +  0.00585  p. 

This  gives  then  for 

p  =  5  10  15  20  25  30 

[a]£  =   —16.38     -16.35     -16.32         16.29    --16.26     -16.24 

For  solutions  containing  up  to  30  per  cent,  of  cocaine,  the 
value,  [«]"  =  —  16.32,  may  be  taken  as  the  basis  of  the  cal- 
culation of  the  percentage  strength.  We  have 

100  Of 


and  with  use  of  a  2  dm.  tube  : 


c=    -  3.o6nr. 

1  O.  Antrick  :  Ber.  d.  chem.  Ges.,  30,  310  (1887). 


502         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 


le^ras 


The  specific  rotation  of  the  hydrochloride  of  cocaine 
been  even  more  fully  investigated  by  Antrick.  The  following 
formula  expresses  the  results  obtained  from  observations  on 
four  preparations  which  in  their  properties  differed  but  little 
from  each  other  : 

W"=     -67.982  +  0.1583^; 
this  holds  for  c  =  o  to  25,  and  for  true  cubic  centimeters  (a^°). 

It  follows  then  for    <* 


c=  5  10  15  20  25 

[a]^  =        —67.19       —66.40    —  65.61        —64.82        —64.02 

The  change  in  the  specific  rotation  with  the  concentration 
is  here  so  considerable  that  it  is  not  possible  to  make  a  mean 
value  of  this  rotation  the  basis  of  a  calculation  of  the  concen- 
tration from  the  observed  angle  of  rotation.  In  the  formula 

loo  a 

=  M^/' 

we  have  to  take  for  \oi\  that  value  from  the  above  series  which 
comes  the  nearest  to  the  expected  concentration,  or  we  may 
make  use  of  the  following  equation,  derived  directly  from  the 
formula  for  the  specific  rotation  : 

(1)  c=  214.72  —  ^46106.8  +  315.86  a 

which  holds  for  the  2  dm.  tube,  t  =  20°,  and  c  —  o  to  25°. 
Finally,  the  angles  of  rotation,  a=   -13.280°  and  a  - 
25-927»   given   by  Antrick   for  the  concentration  c  =  10  and 
c  =  20,  may  be  employed  to  express  c  as  directly  related  to 
the  observed  angle  a.     The  formula  for  this  reads 

(2)  -  0.7337  a  +  0.001454  «*, 
which  holds  for  the  2  dm.  tube  within  the  given  limits. 

In  using  either  of  these  formulas,  care  must  be  taken  to  see 
that  a  is  introduced  with  the  proper  sign,  that  is  the  negative 
sign.  In  using  polarization  tubes  of  other  length  than  2  dm. 
the  value  of  the  angle  read  off  must  be  corrected  before  it  is 
substituted  in  either  of  the  two  formulas,  which  are  based  on 
observations  with  2  dm.  tubes. 

The  agreement  in  the  results  which  may  be  obtained  by  the 
two  formulas  is  shown  in  the  following  table  : 


DETERMINATION   OF   NICOTINE 


503 


c 

c 

Concentration 

Concentration 

Difference 

01. 

calculated  by 

calculated  by 

c\  —  f»- 

Formula  (i). 

Formula  (2). 

5 

3.710 

3.705 

—  0.005 

10 

7485 

7.482 

4-  0.003 

15 

11-331 

H.332 

—  O.OOI 

20 

I5.252 

15.256 

—  0.004 

25 

19.250 

19.251 

—  O.OOI 

30 

23-333 

23.320 

—  0.013 

IX.     Determination  of  Nicotine,  CIOHI4N, 

187. — A  new  method  for  the  quantitative  determination  of 
nicotine  by  the  polariscope  has  been  devised  by  M.  Popo- 
vici.1  The  extraction  of  the  nicotine  from  tobacco  is  best  ac- 
complished by  Kissling's  process  :  20  to  40  grams  of  homo- 
geneous dry  tobacco  powder  is  moistened  with  10  cc.  of  a 
dilute  alcoholic  sodium  hydroxide  solution  (6  grams  of  NaOH 
dissolved  in  100  cc.  of  57  per  cent,  alcohol)  and  extracted 
three  to  four  hours  with  ether  in  the  Soxhlet  apparatus.  The 
ether  extract  is  treated  with  10  cc.  of  a  rather  strong  solution 
of  phosphomolybdic  acid  in  nitric  acid  and  shaken,  by  which 
means  the  nicotine  is  thrown  down  with  other  bases  (mainly 
ammonia)  in  the  form  of  a  quickly  subsiding  precipitate.  Then 
the  supernatant  ether  is  poured  off  and  enough  water  is  added 
to  the  residue  to  make  a  total  volume  of  50  cc  ;  and  finally  8 
grams  of  finely  powdered  barium  hydroxide  is  added.  In  this 
way  the  nicotine  is  obtained  as  a  free  base  in  alkaline  solution, 
which,  after  some  hours  with  frequent  shaking,  is  poured  off 
from  the  yellow  precipitate,  and  polarized.  The  following 
table  was  obtained  from  experiments  with  known  amounts  of 
nicotine  : 


Grams  of  nicotine  in 
50  cc.  of  solution. 

Rotation  in  2  dm.        i  Minute  of  rotation 
tube.                        corresponds  to 
Minutes.                  nicotine  in  grams. 

2.00 

337 

0.00594 

1-75 

298 

0.00588 

1.50 

258 

0.00582 

1-25 

217 

0.00576 

1.  00 

175 

0.00572 

0-75 
0.50 

"8 

0.00564 
0.00562 

0.25 

45 

0.00556 

Popovici  :  Ztschr.  physiol.  Chem.,  13,  445  (1889). 


504         PRACTICAL  APPLICATIONS  OF  OPTICAL  ROTATION 

If  an  alcoholic  solution  of  nicotine,  containing  no  other  ac- 
tive substances,  is  to  be  examined  the  following  formula  by 
Landolt1  may  be  employed  to  find  the  nicotine  content : 


(1)  p  =  311.58  —  -^97082.5  -  449.64-^-  , 

which  holds  for  a  temperature  of  20°,  the  density  d~°,  and  be- 
tween 10  and  90  per  cent,  of  nicotine. 

Further,  with  reference  to  the  nicotine  concentration  : 

a 

(2)  c  =  0.704  ~  —0.000525 

which  obtains  for  20°  and  c  —  10  to  90. 

1  I^an  dolt:  Her.  d.  chem.  Ges.,  ai,  203  (1888). 


PART  SIXTH 


Constants  of  Rotation  of  Active  Bodies 


In  the  following  tabulation  the  data  on  the  specific  rotation 
of  all  active  bodies  in  any  degree  important  have  been  included 
and  the  literature  has  been  fully  considered  to  the  middle  of 
1896.  Only  a  few  of  .the  still  later  observations  could  be  given 
a  place.1  Only  such  specific  rotations  have  received  considera- 
tion for  which  the  data  necessary  for  calculation  (density,  con- 
centration, temperature)  were  given  in  the  original  papers. 

In  explanation  of  the  signs  employed,  see  Part  First,  §§  i 
and  2  of  this  book. 

I.    Hydrocarbons 

(See  also  Terpenes  and  Camphor.) 
Ethylamyl  :     b.  p.  91°,  d'*>  =  0.6895,  [<*]/,  =  ~ 3-93°  " 
/=i7°,  [ci]D  =  +  6.23°)' 
=  60°,  =  +  6.09°  / 

Propylamyl:     /  =  16°,  [<*]  D  =  -f  6.44°  )  4 

=  54°,  =  4- 6.25°  / 

Isobutylamyl:  t  —  20°,  [a]D  =  —  5.88° 
=  52°,  5-66° 

-65°,'  =  -5.20°} 

Diamyl :      b.  p.  i59°-i62°,  dT-  -  0.7463,  [a]D  =  -f  8.69° T 

/  =  21°,  [a\D  =  ~  12.08°  )  8 

=  78°,  =  4-  12.06°  J 

=  19°,  =  4-  10.01°  » 

These  bodies  were  all  made  from  active  amyl  iodide. 

1  [In  the  translation  the  most  important  observations  to  the  middle  of  1900  have 
been  included. — Tr.J 

Just:  Ann.Chem.  (lyiebig),  220,  154. 

Welt  :  Compt.  rend.,  119,  743. 

Welt  :  Loc.  cit. 

Welt :  Loc.  cit. 

Guye  and  Amaral  :  Arch.  sc.  phys.  Geneve,  [3],  33,  4<>9- 

Just :  Loc.  cit. 

Welt  :  Loc.  at. 

Guye  and  Amaral :  Loc.  cit. 


506 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


2 .  Alcohols  with  One  Atom  of  Oxygen 
/-AMYL  ALCOHOL   C,H5.CH3.CH.CH2OH. 


Commercial 


fermentation  alcohol  :  aD  =     -  2°  to  —  4°  for  i  dm. 

Preparations  purified  from  inactive  isomers  by  L,e  Bel's 
method  (repeated  treatment  with  gaseous  hydrochloric  acid, 
through  which  the  inactive  part  is  first  converted  into  amyl 
chloride  and  may  be  separated  by  distillation)  gave  : 

«/>  =  —  4-53°  to  4-63°  for  i  dm.  [>]/>=  -  5-7°  when 
d  =  o.Si.1  [«]/>=  -5-  2,  ft'22  =0.8  1  8,  boiling-point  128.5°  to 
129°  (768  mm).2 

According  to  Schiitz  and  Marckwald 
were  not  yet  pure. 

Derivatives  of  /-Amyl  Alcohol 


these  preparations 


Amyl  chloride  :b.  p.  97  to    99 


=  +  1-24  ) 
=  +  3-5  \ 
~-  +  5-41  > 


=  0.886,  [^/,= 

Amyl  bromide:    "     117   "  120°,    "  =  1.225, 
Amyl  iodide :       "    144    "  145°,     "  =  1.54, 
Amyl  iodide:      "    144   "  146°,  </20  =  1.538,    "        =  +  4-555 

Add  Esters  and  other  Amyl  Compounds 

For  these  bodies,  which  are  all  liquid,    the   following  data 
have  been  given,  and  by  : 

i.  WARDEN.6     Rotation  of  the  amyl  alcohol  used,  [a]z?  =  —  4.78 


Boiling-point. 

mm. 

rf. 

[- 

<* 

141    142^ 

0877.4 

o  868  <; 

i 

n  8662 

i 

2  87 

752 

2.O3 

i 

,1U 

Amyl  brom-*.y0-butyrate  

I29 

55 
50 

1.1851 

.27 

757 

2  I 

o  0760 

_i_ 

«;  60 

Dianivl  maleate  

167    768 

i 

9>vy 

188 

_L 

574 

Diamyl  chlormaleate   

176 

68 

I 

•74 

4  60 

Diamyl  0-phthalate-  •         • 

1/0 

23 

5 

Amvl  acetic  acid  .  . 

232 
2T2-2I7 

43 

O.QIA6 

4- 

S.«;7 

I^c  Bel :  Bull.  soc.  chim.,  [2],  ai,  542  ;  Compt.  rend.,  77,  1021. 

Rogers  :  J.  Chem.  Soc.,  63,  1131. 

Schiitz  and  Marckwald  :  Ber.  d.  chem.  Oes..  39,  59. 

I*e  Bel  :  Bull.  soc.  chim.,  [2],  25,  545. 

Walden  :  Ztschr.  phys.Chem.,  15,  647. 

/bid.,  15,  642  fT. 


DERIVATIVES   OF  /-AMYL   ALCOHOL 


507 


Boiling-point. 

mm. 

d. 

[«]" 

180-182 
228-230 
262-263 
235-238 
268-270 

(m.p.  90°-9i 
244-246 
280 
228-232 
265 

(m.p.  51° 
185-186 

760 

775 
760 
760 

775 
c,  acet( 

760 
768 

aceto 

•• 

0.8765 
0.8631 
0.8894 
0.8701 
0.8594 
>ne  c  —  6  67  ) 

+    6.56 

4-    7-oi 
+  18.27 

•     17  OQ 

i     *  /  •  fy 

4-  13-96 
+   5-25 
+  10.14 
4-   5-82 
+  11.48 
inactive 

4-    1.25 
4-    7-94 

0.9665 
0-9445 
0-9455 
0.9120 

tie  c  —  20) 

Diethyl  diamylmalonate  

Ethyl  diamylacetoacetate  •  •  • 
Diethyl  a  m  y  1-^-nitrobenzy] 

0.8459 

2.  \Y.\LDEN.1     Rotation  of  the  amyl  alcohol  used,  \_a]D  =  —  4.7° 


Boiling-point- 

mm. 

d. 

[«]£. 

\tnvl  /-lactate  •  • 

105° 

22 

o  0672 

+    2.64 

1WO 

17 

o  0667 

-I    Q7 

I  7O—  171 

A/ 
2O 

I  0520 

-j-        2.76 

ififi    167 

QA    O2 

Amyl  /-phenylchloracetate  -  . 
Amyl</-phenylchloracetate.  . 

166-167 
169-170 
IQI     IQ2 

A/ 
20 
24 
2O 

1-UJOU 

1.0832 
1.0826 
i  0180 

+        3-23 
+    26.79 

-f-    ^  so 

2O 

I  OI  76 

-    6  88 

Diamyl  z-chlorsuccinate  
Diamyl  </-chlorsuccinate  .... 

187-188 
I87 
2O8 

22 
22 
2O 

1.0314 
1.0305 

I  064 

+    3-75 
4-  25-15 

-1-        -2    77 

Diamvl  </-tartrate  

2o8 

2O 

I  06^6 

1     17  7^ 

3.  WALDEN.2     Rotation  of  the  amyl  alcohol  used,  [<*]/>=:  —  4.8' 


Boiling-point. 

mm. 

d. 

Ml: 

Diamvl  ina.lc3.te  •••  

170° 

2Q 

O  Q747 

-i-  /i  62 

i/u 

T«(- 

2C 

T  OC^^ 

i  4  01 

Diamyl  brommaleate  •••*••• 

10O 

17^—177 

•'D 

I  ^ 

1-*JC>OO 
I    I  ^61 

1    4-uo 

4_  4  eg 

ygc    187 

AO 

T  C 

i  168^ 

+    r   QQ 

100    10/ 

1O 
2C 

o  0661 

o-yy 

1     d   TJ 

1/:7 

1      H-14 

Diamyl    antidimethylsuccin- 
a^e  

i/«j-i/^ 
168-169 

T  r 

u  v°o/ 

4-97 

1      7   A2 

Diamyl  paradimethylsuccin- 

i8< 

1O 

•in 

OQJ.^2 

T^  3-42 
4_  ,  66 

Diamvl  mesotartrate  

10o 

ow 

17 

I  06^8 

1-  /I    77 

A/ 

16 

I  064 

1    4.// 

+    ?    77 

3-37 

1  Ztschr.  phys.  Chem.,  17,  705  ff. 

2  y*/rf.,  20,  378. 


508  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

4.  WALDEN.1     Rotation  of  the  amyl  alcohol  not  given 


Boiling-point. 

mm. 

rf. 

[«]??. 

T78-I  7Q° 

76* 

o  8690 

_(_  2  8l 

i/o—i  /y 

7  CQ 

o  8018 

I         A     -J* 

I  7O    171 

/Du 

761 

"•"Vo0 
o  8619 

\    4-^4 

+     7     TQ 

7e 

20 

o  8781 

I     1  ZI 

/O 
T7C     i  Of, 

or 

O  O1O2 

T  ,5-D1 
1     i  76 

rfc 

O 

IO 

"•yoy^ 
o  0606 

T  O'/° 

_L    C    Q7 

XVJO 

187  188 

22 

I  O1  1  A 

o-yo 

1      1   7C 

187 

14 

I  0560 

1     O'/O 

_L   c  78 

Diamyl  methylsuccinate  •  •  •  • 

172 
181   I&A 

18 
20 

0.9529 

o  9698 

+  3.67 

or 

o-9v) 

241    2/11 

O 

26 

•9973 

I  OO2Q 

+  6  16 

Amyl  hydrocinnamate  
Amyl  cinnamate  

Z41    "43 

.    172 
IQ2 

28 
2O 

0.9721 
O  QQQ2 

+  2.26 

I      7   rj 

iy^ 
2IO 

*y 

\j.  yyy- 

i      /'O1 
!      r   c8 

Amyl  a-naphthoate  

222 

2Ac 

oo 

25 

IOO 
100 

l.UUj^ 

1.0605 
I  Oil  I 

1      J'O° 
+  5-28 
+  Q  1A 

J05 

I'tjo6l 

V-o4 

5.  GUYE  AND  CHAVANNE.'2     Rotation  of  the  common  amyl  alcohol  used, 
=  —  4.4.     Rotation  of  the  sec-amyl  alcohol  not  given 


r/v-|20—  22 

\.a\D 

[«»^ 

+  2  OI 

-4-  I  08 

Atjiyi  acetate  

1     2   Cl 

i    *«^p> 

4-2  cr 

i      -'•OO 
+  2   77 

I   *.5i 

4-  2  68 

*•  // 

4-  2  60 

+  2   r,i 

•\.myl  palmitate  

+  T   AZ. 

+  T    l6 

1  '4o 

d 

[«]/. 

o  962 

A  06 

sec-  Amyl  propionate  

o  8oc 

—  8  cc: 

Sfc-  \tsi\\  butvrate« 

u-°95 
n  8So 

°-oo 

8   2? 

fifi  w-Amyl  benzoate  

o  988 

O.23 

4-  A  06 

Afj#f-Amyl  phenylacetate     •                 • 

n  08.2 

1    i  8.1 

o  076 

1     O'°*» 
+  2  11 

w.y/u 

•*•  *o 

6.  GOLDSCHMIDT  AND  FREUND.3     Rotation  of  the  amyl  alcohol  used, 

O]z>  -   —  4.29.     The  following  solid  esters  were  used  in 

chloroform  solution 


p 

[>]/. 

Amyl  phenylcarbaminate  

C    0/l8 

Amyl  0-tolylcarbaminate 

5728 

4.  iy 
t     ^  fifi 

.320 

5106 

4-  i  81 

Amyl  ^-tolylcarbaminate  .  . 

.yju 
1.277 

T  «5'°j 
4-  4.d7 

1  /tschr.  phys.Chem.,ao,573.    «Compt.  r«nd.,  120,452.    3Ztschr.  phys.  Cheni.,  14,394. 


MIXED   AMYL   ETHERS 
7.    GUYE  AND  GOUDET.1 


509 


[«]/> 

A   l6 

4-ou 

1        T     C^ 

6  10 

i  48 

O-H-0 

8.  GUYE  AND  AM  ARAL2  investigated  the  following  derivatives  of  /-amyl 
alcohol  at  different  temperatures 


t 

[«3z» 

t 

[Oz> 

16° 

15 
20 
18 
18 
18 

-  4-52 
-r  14-09 
-  11.13 
+  2.51 

+  3^7 
4-  2.54 

76° 

72 

5i 
62 
60 
57 
5i 
62 

57 

' 

412 

+  H.I4 

9-97 
+  2.07 

+  3-13 
+  2.51 
-f  2.97 
-  0.99 

-  4.71 

27 
18 
18 

3.00 
-  0.87 
-r  5-59 

Amylamine  hydrochloride.3     Water,  p  =  7.84, 


=  -f 


12.7' 


Mixed  Amyl  Ethers 
GUYE  AND  CHAYANNE*  give  the  following  data : 


Boiling-point. 

rf 

WD 

87  «;-  88  *° 

O  7«\A 

-\-  o  10° 

IO7   ^    TOO 

O  7^Q 

o  61 

1U/'O   1W7 

o  781 

•     O  QO 

1^5       »•*/ 

Txr         TX.7 

U.  /Oj 

O  771 

,     \J.^J 

4-  o  06 

T.JP          T47 

O  774. 

+  O  7O 

Cctvl-Eunyl  ether  •  .  .  .  . 

14D        X4/ 

T^C      —147 

o  805 

—  O  ^1 

211          212 

O  QI  I 

1  i  81 

•'.S1        -'o-' 

1  Compt.  rend.,  121,  827. 

-  Arch.  Sc.  phys.  Genfcve  [3],  33,  409;  Compt.  rend..  120,  1345- 

3  Plimpton:  J.  Chem.  Soc.,  39,  332  ;  Compt.  rend.,  92,  531,  883. 

4  Compt.  rend.,  120,  452. 


510  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

WEI.T1  gives  for  other  ethers  : 


/ 

i*]* 

T7° 

+      A   r»O 

-1/ 
TQ 

4.0 

1          A     ~{. 

X7 

i    4-2° 

1     i  8£ 

22 

:      3'°° 

4,5-Methyl-propyl-phenol-atnyl   ether.  . 
4,6-Methyl-propyl-phenol-amyl   ether.  . 

18 
19 

3-93 

4-4.17 
+  4.01 

/-\TT  /-*    TT 

2.  </-HEXYL  ALCOHOL,     H>C<CH—  CHOH'   From  Ro 
man  camomile  oil  : 

Boiling-point  154°  (at  758  mm.), 

du  =  0.829,  /=  17°,  [>]„=:  +  8.2°.' 

3.  METHYL-HEXYL  CARBINOL, 


Obtained  by  reduction  of  the  following  compound  : 


Methyl-hexyl  ketone. 
tate  : 

/=2i 

'=57 


By  saponification   of   amyl  acetoace- 


=  +  5-06 
=  '  +  4*1 


3.  Alcohols  with  Two  to  Four  Atoms  of  Oxygen 
A  few  optically  active  compounds  of  this  kind  are  known, 
such  as  /-propyleneglycol,  but  the  optical  constants  of  none  of 
them  have  been  accurately  determined.     As  derivatives  of  such 
alcohols  we  may  consider  : 

Diphenyl-ethylene-diamine,  §H5>CH  ~~  CH<NH5'  " 
Obtained  by  reduction  of  benzyl  dioxime.     Melting-point  90° 
to  92°.     Split  as  bitartrate. 

Ether:  /=  15° 
rf-Base.      0],=:  +  I34-81 
/-Base.      \fi\D-      -  128 

1  Ann.  chim.  phys.,  [7],  6,  115. 

2  van  Romburgh:  Rec.  trav.  chim.,  5,  220. 

3  Welt:  Compt.  rend.,  119,  855. 
«  Welt  :  Loc.  cit. 

6  Feist  and  Arnstein:  Ber.  d.  chem.  Ges.,  a8,  3167. 


ALCOHOLS  WITH  SIX  ATOMS  OF  OXYGEN  511 

/,  5-Tetrahydronaphthylene-diamine.       Split     as    bitartrate. 
The  hydrochlorides  in  aqueous  solution  gave  at  17.5°  : 
</-Base.  c—  2.44,  \a\D  —  +  8.15' 
/-Base.  <:  =  3.96,  \oi\D  —  —  7.5 

4.  Alcohols  with  Five  Atoms  of  Oxygen 
Pentitols,  CH,OH.(CH.OH)3.CH.,OH. 

ARABITOL,  melting-point  102°.  Held  by  Kiliani,2  but  im- 
properl}11,  as  inactive. 

Cold  saturated  borax  solution,  p  =  9.05,  [«]  #  =  —  5-3°. 
After  36  hours  still  unchanged.3 

XYLITOL,  inactive.  Bertrand's  statement,  [«]  =  -f  0.5°  is 
wrong.4 

ADONITOL,  inactive,  also  in  borax  solution.5 

RHAMNITOL,  CH3.(CH.OH)4.CH2OH.  Triclinic  prisms. 
Melting-point  121°.  Water,  p  =  8.648,  [«]?  =  =  -f-  io.7°.6 

5.  Alcohols  with  Six  Atoms  of  Oxygen 
Hexitols,  CH2OH.(CH.OH)4.CH2OH. 

^-MANNITOL.  The  behavior  in  aqueous  solution,  the  action 
of  borax  and  other  salts,  also  of  acid  sodium  and  ammonium 
molybdates,  are  given  in  §  70,  pp.  253  to  256. 

In  alkaline  solution,  left  rotating.  Water  with  8  per  cent  of 
NaOH,/  =  8,  \a]D=  -  3.4°.7 

Derivatives  : 
Nitromannitol,   C6H8(O.NO2)6 : 

Ether p  =  4.2,  [«]y  =  -f  70.2°.* 

Alcohol p  =  2,      [a]y  =  -f-  63.7.9 

Alcohol c=  7.5,   [«]/>=  -h  4o.10 

Hexachlorhydrin,  C6H6C16 : 
Benzene [^]  D  =  +  18.5°." 

1  Bamberger:  Ber.  d.  chem.  Ges.,  23,  292. 

-  Ibid...  20,  1234. 

3  Fischer,  Piloty  :  Ibid.,  24,  521. 

*  Bull.  soc.  chim.,  [3],  5,  554. 

5  Fischer:  Ber.  d.  chem.  Ges.,  26,  633. 

15  Fischer,  Piloty  :  Ibid.,  23,  3102. 

~  Miintz,  Aubin  :  Ann.  chim.  phys.,  [5],  10,  566. 

8  Krecke:  Arch.  Neerl.,  VII,  1872. 

•  Krecke:  Ibid.,  VII,  1872. 

10  Krusemann:  Ber.  d.  chem.  Ges.,  9,  1468. 

11  Mourges:  Compt.  rend.,  HI,  112. 


512  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

/-MANNITOL.     In  borax  solution  strongly  left  rotating.1 

Isomannitol.  Water,  p  =  6,  [<*]„  =  -f  91.36°.  Alcohol, 
P  =  3,  [«]/>  =  +  94-66V 

DULCITOL.  Inactive,  also  in  borax  solution/5  Bouchardat's 
statement4  that  diacetyl  and  tetraacetyl  dulcitol  are  slightly 
right  rotating  has  been  contradicted  by  Crossley.5 

SORBITOL.     See  statement  in  §  70. 

</-TALITOL  The  aqueous  solution  is  slightly  right  rotating, 
the  borax  and  alkali  solutions  slightly  left  rotating.6 

RHAMNOHEXITOL,  CH3.(CH.OH)5.CH.,OH.  Water,  c  = 
10.4,  /  =  20,  [a]D  =  +  14.0°.  ' 

aMNOSiTOL,  C6H,,O6  and  hydrate,  C6H,,O,  +  2H,O.  Water, 
p=  10  (anhyd),  \a\D  =  -f  65.0°.  8 

Methyl-d-inositol,  pinitol,  C6HUO6.CH3. 

Alcohol  ..................   \CL\D  =  -f  65.51°  9 

Water  ....................    [«]/>  =  +  65.7     10 

Matezttol,  identical  with  pinitol.     Melting-point,    187°. 

Water  ....................    [a]D  =  +  66.0°  » 

Water,  c  =    3.625,  [a]/,  =  +  64.7     « 

Water,  r  =  11.867,  [a]7J  =  -f  65.2     1S 

/-INOSITOL.     Water,   [«]/,=    -  65°.  u 
Methyl-l-inositol,  quebrachitol  .     Water,    [a]^  =  --  80°.  1 


°  15 


6.     Alcohols  with  Seven  and  More  Atoms  of  Oxygen 

Heptitols,  CH,OH.(CH.OH)S.CH,OH. 
^-MANNOHEPTITOI,,  C7H16O7,  perseitol.  Perseitol  from  Laurus 

I  Fischer:  Ber.  d.  chem.  Ges.,  33,  375. 

-  Fauconnier:  Bull.  soc.  chim.,  [2]  41,  119. 

Fischer,  Hertz:  Ber.  d.  chem.  Ges.,  25,  1247. 

Ann.  chim.  phys.,  [4],  37,  68,  145. 

Ber.  d.  chem.  Ges.,  35,  2564. 

Fischer:  Ibid.,  37,  1524. 

Fischer,  Piloty:  Ibid.,  33,  3827. 

Maquenne:  Compt.  rend.,  109,  968. 

Maquenne:  Ibid.,  109,  812. 
10  Combes:  Ibid.,  no,  46. 

II  Combes:  Ibid.,  no,  46. 
'*  Girard:  Ibid.,  no,  84. 

13  Girard:  Ibid.,  no,  84. 

14  Tanret:  Ibid.,  109,  908. 
»•  Tanret:  Loc.  tit. 


ACIDS  WITH  TWO  ATOMS  OF  OXYGEN  513 

persea  L.,  is  inactive  according  to  Miintz  and  Marcano,1  but 
according  to  Gernez,2  slightly  left  rotating,  and  in  aqueous  so- 
lution for  c  -  7.36,  [tf]/1  =  —  1.22°. 

Variety  from  ^/-mannoheptose  :  for  cold  saturated  bornx  so- 
lution, c=S,  right  rotating,  [>]£  —  -f-  4-75°-3 

On  the  action  of  acid  sodium  and  ammonium  molybdate,  see 
^70,  p.  256. 

VOLEMITOL,    C.H16O7.     Water,  p—  10,  [>]£=:  -f  1.92°.* 

GALAHEPTITOL,  CTH16H:.  Water  -f-  borax,  p  =  8.8,  [ci]*D 
=  -4-350-5 


C8H1SO,..     Water,  p=  10.24,  &  =  1-038, 
[a]  5?  =  -f-  2°."    After  addition  of  borax  three  times  as  strong. 

7.     Acids  with  Two  Atoms  of  Oxygen 

d-  VALERIC  ACID,  methyl-ethyl  acetic  acid,  C,H5.CH3.CH. 
CO,H.  From  /-amyl  alcohol. 

[From  amyl  alcohol  of  [a]/,  =  —  4.4°.  Boiling-point,  173° 
to  174°,  (730  mm.).]  d"  —  0.938,  [a\D=  +  13.64°.  T 

[From  amyl  alcohol  of  [<*]}5  =  —  5-2°.  Boiling-point, 
174.5°  (768  mm.).]  </»  =  0.936,  [a]^=  +  13.  9°,s  [a]%  = 
-h  11.27°;  |>]g=  +  io.84°.9 

According  to  Schiitz  and  Marckwald,10  valeric  acids  with  the 
rotations  given  must  contain  still  about  20  to  25  per  cent,  of 
impurities.  For  the  pure  substance  [oi\D  must  be  -f  17°  to 
1  8°  ;  see  /-valeric  acid. 

Derivatives 

VALKRALDEHYDE,  Boiling-point,  92.5°,  d°  =0.8209,  [«]/, 
=  -f-  i.7011  (maximum  value).  \a]l%  =  -\-  14.09°  ;  [<*]%  = 
-h  11-14°." 

I  Ann.  chiin.  phys.,  [6],  3,  279. 
Compt.  rend.,  114,  480. 

Fischer  and  Passmore:  Her.  d.  chem.  Ges.,  23,  2226. 
Fischer:  Ibid.,  28,  1973. 
Fischer:  Ann.  Chem.  (Liebig),  288,  147. 
Fischer  :  Ibid.,  270,  99. 

Guye  and  Chavanne:  Compt.  rend.,  116,  1455. 
Roger:  J.  Chem.  Soc.,  63,  1134. 

Guye  and  Aniaral:  Arch.  sc.  phys.  Geneve,  [3],  33,  409. 
Ber.  d.  chem.  Ges.,  29,  59. 

II  Erlenmeyer  and  Hell:  Ann.  Chem.  il^iebig),  160,  257. 
1--  Guye  and  Amaral:  Arch.  sc.  phys.  Geneve,  [3],  33,  409. 

33 


5H 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


YALERALDOXIME,  |>]~  =  -f  11.13°;  Ms/>  = 
ESTERS  OF  </-  VALERIC  ACID. 


9-97 


B.p.  (730  mm.) 

rf«. 

M. 

1  13  to  115° 

o  882 

4-  16  S\° 

•I 

I  7  1    to   177 

o  864 

4-  17  44 

From 

I  ^4  to  1^7 

o  860 

0'** 

4-  ii  68 

valeric 

W  Riifrvl  p<;tpr 

177  to  176 

o  8^6 

_L    jo  60 

acid.- 

Isobutyl  ester  

165  to  167 

o  8^5 

_j_   jo  48 

[a     = 

246  to  2^0 

o  982 

+       r    C7 

J-OO 

For  further  observations  of  Guye  and  Guerchgorine,  see 
Compt.  rend.,  124,  230. 

/-VALERIC  ACID.  First  obtained  by  Schiitz  and  MarckwakT 
by  resolution  of  the  synthetic  acid  (fromethyl-methyl-malonic 
acid),  by  aid  of  brucine.  Boiling-point,  173°  to  174°.  The 
rotation  for  the  following  colors  was  determined  by  use  of  the 
ray  filter  method,  §158. 


Wave-lengths. 

A. 

665.  9  MM 

589.2 

533-0 
488.5 
448.2 

Temp.  20°. 

,    rfr=«-«4. 

Temp.  30°. 
d*°  =  0.926. 

Red 

r-l  —         T-   -no 

Pal                   T5   QT° 

Yellow  ^Na^ 

LaJ             I3-5° 
17-85 
22.57 

27-75 
34.19 

LaJ          12.91 

17.02 
21.44 
26.29 
32.63 

</-CAPROic  ACID,  /S-/3-methyl-ethyl-propionic  acid,  C2H5. 
CH8.CH.CH2CO2H. 

From  </-hexyl  alcohol.  Boiling-point,  196°  to  198°  (770 
mm.),  dl*  =  0.930.  [flr]y;  =:  +  8.92°.* 

HEXYL  ESTER  OF  CAPROIC  ACID.  Boiling-point,  233°  to 
234°  (768  mm.),  d^  =  0.867.  \a]?,=  -f  i2.86°.:> 

For  other  esters  see  Guye  and  Guerchgorine/ 

i  Guye  and  Amaral:  Loc.cil. 

-  Guye  and  Chavanne  :  Compt.  rend.,  116,  1455. 

:t  Ber.  d.  chem.  Ges.,  39,  52. 

4  v.  Romburgh:  Rec.  trav.  chim.Pays  Ha>  ,  5,  222. 

Komburgh. 
"  Compt.  rend.,  124,  130. 


ACIDS  WITH  THREE  ATOMS  OF  OXYGEN  515 

^-AMYLACETIC  ACID,  C,H5.CH3.CH.(CH,.CH,CO,H).  By 
saponification  of  amyl  acetoacetate. 

Acid /      20°,   [«]  n  =  -  8.44°,  /-   54J   [«]/>  =  +  7-64° l 

Methyl  ester /       25.         "         =  +  6.71,     *  =  75.        "        =+5-92 

Ethyl   ester /  =  21,         "         -  +  6.66,     /  =  72,        °        =  +  5.87 

For  amyl  esters  see  under  amyl  alcohol. 
PARASORBIC  ACID,  sorbinoil,  C6H8O2.      \_a~\j  =  +  40. 8°. 2 
</-PIPECOLINIC  ACID,  C5H10NCO2H.     Obtained  by  resolution 
of  the  racemic  acid  by  means  of  ^-tartaric  acid. 

Water,  p  =  19.93,      [or]  2j  =  +  33-4° 
Water,/   ^    9.92  "      =  +  35.7 

/-PiPECOLiNic  ACID.     Made  by  aid  of  /-tartaric  acid. 
Water,  p  =    9.92,  [a]%  =    -  34  8°  ! 

8.  Acids  with  Three  Atoms  of  Oxygen  and  Derivatives 

</- LACTIC  ACID,  CH3.CH.OH.CO2H.  Sarcolactic  add  (para- 
lactic  acid).  As  first  shown  by  Wislicenus,4  certain  amounts 
of  the  ester  anhydride,  C6H10O5,  and  of  the  lactide,  C6H8O4,  are 
always  formed  in  concentrating  aqueous  solutions  of  sarcolactic 
acid  ;  both  of  these  bodies  have  a  strong  left  rotation.  The 
right  rotation  of  the  acid  is,  therefore,  found  too  small.  On 
standing,  the  anhydrides  in  aqueous  solution  pass  gradually 
into  acids  and  the  rotation  increases.  See  §75,  p.  280.  As 
highest  values  there  were  found  : 

c       42.97,      [tf]/,  —  +  2.91° 

32.84,  3.46 

21.25,  2-66 

7.38,  2.78 

Also  by  Hoppe-Seyler  and  Araki/' 

P  —  39-85,    d    -  1.0907,    [«]^5  =  +  3-48  to  3.54° 
22.90,  1.0538,  2.53 

11.19,  1-0273,  I-57 to  1.89 

For  the  rotation  of  the  pure  acid  made  by  Krafft  and  Dyes,7 
no  data  have  been  given. 

1   Welt  :  Compt.  rend.,  119,  855. 

-  Doebner  :  Ber.  d.  chem.  Ges.,  37,  348. 

Mende  :  Ibid.,  29,  2887. 
4  Ann.  Chem.  (Liebig),  167,  302. 

Wislicenus:  Ibid.,  i67,  324  10327. 
"  Ztschr.  physiol.  Chem.,  ao,  369. 
:  Ber.  d.  chem.  Ges.,  28,  2589. 


5l6  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Anhydride. — A  preparation  wrhich  contained  84  per  cent,  of 
C6HIOO5  and  16  per  cent,  of  C3H4O.,  gave,  in  alcoholic  solution, 
c=  19.54,  M/>  =  —  85- 90-1 

If  but  a  few  per  cent,  of  the  anhydrides  are  present  in  lactic 
acid  solutions,  they  exhibit  left  rotation. 

d-Lactic  Acid  Salts. 

These  all  show  left  rotation. 

Zinc  Salt,  Zn(C3H5O3)2  +  2H2O.  The  rotation  of  aqueous 
solutions  increases  slightly  on  dilution.  There  was  found  for 
the  hydrated  salt  : 

i.  c  =  i6.o5,2        [«*]/,=  -  6.36°         2.  p  =  9.08,      \ci\D=  -  6.56° li 
n.oi,2  6.36  8.29,  6.64 

7.47,  6.83  653,  6.84 

6.13,  7.41  5.89,  6.83 

5.26,  7.60  4.18,  7.55 

3.  £=7-49,     [oi\D=    -6.83°* 

Zinc  Ammonium  Salt,  Zn.NH4(C3H5O3),  +  2H2O. 

Water,  c  =  8.00,      [#]  D  - -    —  6.06° .* 
Calcium  Salt,  2Ca(C3H5O3)2  +  gH,O. 

Water,  c  =  7.23,      [d]D=    -  3-87°  5 
Water, /> .-    6.25,      [«]  „  .      -3.85" 

Lithium  Salt,  Li.C3H5O3- 

Water,  p  ^  5  to  12,  [«]  /(        -  10.95  to  12.28°  (i 
d-Lactic  Acid  Esters. 

Methyl  ester rff       i.ioo,    [a]7,  •      -  11.1°   \7 

Propyl  ester ^—1.004,    [«]/,=    -17.06   < 

For  further  determinations  see  Frankland  and  Henderson.8 
/-LACTIC  ACID.     By  resolution  of   fermentation  lactic  acid 
by  means   of  strychnine    (§33),  or  by   the  action  of  Bacillus 
acidi  laevo-lactici  on  cane-sugar. 

1  Wislicenus:  Ann.  Chem.  (i,iebig),  167,321. 

2  Supersaturated.     Wislicenus:  Ibid.,  167,  332. 

»  Hoppe-Seyler  and  Araki:  Ztschr-  physiol.  Chem.,  ao,  371. 
4  Purdie  :  J.  Chem.  Soc.,  63,  1154. 
6  Wislicenus  :  IMC.  cit. 

•  Hoppe-Seyler  and  Araki  :  Lot:  cit. 
'•  Walker:  J.  Chem.  Soc.,  67,  916. 

*  Proc.  Chem.  Soc.,  n,  54  (1895). 


ACIDS  WITH  THREE  ATOMS  OF  OXYGEN  517 

Water,  c  -64.8,     [ci\D=    -  4-3°  ' 

Water,  p  =  12.43,          d  =  1.0348,    t  =  23.3,     [«]          -  4.72°  ! 

Water,  />—    6.57,          </—  1.0192,    t  -—  23.6,         "         —5.86 

l-Lactic  Acid  Salts 

They  all  show  right  rotation  in  aqueous  solution. 

Zinc  Salt,  Zn(C3H5O3)2  +  2HA 

1.  c=       i6;o8  12.66  5.85  5.57  )  3 
[«U  =  +    54        -f    5-2          -f  6.5              6.3°  / 

2.  c=  7-484,     [a]/,  =  +  6.8i°.* 

3-         />  =  6.751,          </;?  =  1.0318,     [>],>  =  +  6.320.5 
Zinc  Ammonium  Salt,  Zn.NH4(C3H5O3)3  +  2H2O. 
/  -  8.63,     df  =  1-035,     [or]g  -  -f  6.49°  I6 
/  =  5.87,    "    ==1.024,  -  +  7.°7     ' 

Lithium  Salt,  LiC3H5O3. 

p  =  3.  7  to  9.1,     [tf]^  =  -r  13.5  to  12.7°  7 
Sodium  Salt.     See  §57,  p.  202. 

Ester. 

d?>  =1.030,     [flf]^  =  +  14-52°  8 


Chlor-propionic  Acid,  CH3.CHC1.CO2H. 

Methyl  ester  of  the  rf-acid-  d'°    -=  1.1520,  [a]D  =  +  19.01°  |u 

Ethyl  ester  of  the  flT-acid  ...  "      =1.0888,       "      =+12.86  / 

Methyl  ester  of  the  /-acid  ••  d\    =1.158,         "      =  —  26.83  ^  12 

Ethyl  ester  of  the  </-acid..  ^4"5=  1.087,         "      =  +  J9-51  [ 

Propyl  ester  of  the  d-acid  ••  ^J    =1.065,         "      =  -+-  n.o  J 

Brom-propionic  Acid,  CH3.  CHBr.CO2H. 
Methyl  ester  of  the  </-acid.  ^^    =  1.482,     [a]D  =  +  42.65°  ^  " 
Ethyl  ester  of  the  /-acid...  flf^°    =1.386,         "  —31.45 

Propyl  ester  of  the  d-acid  ••  df^4    ^1.315,         4<      =  —  21.98 

Schardinger  :  Wien.  Monatsh.,  il,  551 

Hoppe-Seyler  and  Araki  :  Ztschr.  physiol.  Chem.,  ao,  369. 

Schardinger  :  Loc.  cit. 

Purdie  :  J.  Chem.  Soc.,  63,  1154- 

Purdie  and  Walker  :  Ibid.,  61,  762. 

Purdie  and  Walker  :  Ibid.,  61,  761. 

Hoppe-Seyler  and  Araki:  Ztschr.  physiol.  Chem.,  20,  372. 

Walker  :  J.  Chem.  Soc.,  67,  917. 

Klimenko  :  J.  russ.  chem.  Ges.,  12,  30. 

Frankland  and  Henderson  :  Prrc.  Chem.  Soc.,  11,  54  (1895). 
»  Walden  :  Ber.  d.  chem.  Ges.,  28,  1293. 
«  Walker  :  J.  Chem.  Soc.,  67,  918. 
13  Walker  :  Loc.  cit. 


518  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

ALKYL  OXYPROPIONIC  ACIDS.  Purdie  and  Lander1  have  pre- 
pared a  number  of  active  compounds  by  resolution  of  inactive 
methoxypropionic,  ethoxypropionic,  and  propoxypropionic 
acids  by  aid  of  cinchonidine  and  morphine.  The  authors  be- 
lieve that  a  nearly  complete  separation  of  one  component  in 
each  case  was  secured  and  numerical  values  are  given  for  the 
free  acids  and  their  sodium  and  calcium  salts  as  follows  : 

/-Methoxypropionic  acid,  water  ----  c  —  13.^75  [**]/>  =    —  71-09° 

Sodium  salt,  water  ----  c  =  16.530  —  49.43 

Calcium  salt,  water  ----  c  •=    9.53  "          —38.09 

d-  Ethoxypropionic  acid,  water  ----  c=  29.374  -f-  56.96 

Sodium  salt.  water  ----  c=  17.965  +  48.09 

Calcium  salt,  water  ----  i  —  26.87^  -f  38.40 

d-  Propoxypropionic  acid,  water....  £-=11.450  +55-63 

Sodium  salt,  water.  .  .  .  £  =  30.750  -f-  48.94 

Calcium  salt,  water  ----  c  =  12.010  -f  48.54 

Purdie  and  Irvine"  have  determined  the  optical  behavior  of 
methoxypropionic  and  ethoxypropionic  acids  and  esters  pre- 
pared from  active  lactic  acid. 

/S-OXYBUTYRIC  ACID,  CH8.CH.OH.CH,.CO,H 
The  /-form  has  been  found  in  diabetic  urine.3 
Acid.     Water,  [a\D  =  —  20.6°.  4 

[«]/>  =  —  23-4.' 

Sodium  Salt.  Water,  p  =  32.1,  [oi]D  =  —  15°.  4  p  =  20.9, 
^=1.0900,  \a\D——  I3-930.6 

Stiver  Salt.    [oi\D  =  —  10.1°  ;4  c  =  1.4,    [«]/,=  —  8.64°.7 
A  series  of  esters  of  d-  and  /-oxybutyric  acid  has  been  in- 
vestigated by  Guye  and  Jordan.8 


In  hydrochloric  acid  solution,  left  rotating. 


Kef 


J.  Chem..Soc.,  73,  862  (1898). 
/*"/.,  75,  483  (1899). 

Minkowski :  Her.  d.  chem.  Ges.,   17,  Ref.  334,  535.     Kiilz  :  Ber.  d.  chem  G«8.,  17, 
534  ;  18,  Ref.  451. 
Minkowski. 

Kiilz :  Ber.  d.  chem.  Ges.,  ao,  Ref.  591. 

Deichmiiller,  Szymanaki  and  Tollens  :  Ann.  Chem.  (I«iebig),  aa8,  94. 
Kiilz. 
Compt.  rend.,  lao,  1274  and  tao,  630. 


ACIDS  WITH  THREE  ATOMS  OF  OXYGEN  519 

From  conglutin  : 

20  per  cent.  HC1 c  --  4-73,     M/>         ~  l7-5° 

From  active  (conglutin)  leucin  : 

20  per  cent.  HC1 c  —  5.00,      [«]/,=    -  T7-3° 

From  inactive  leucin  : 

20  per  cent.  HC1 c  =  4-37.     [^]z?=    ~'7-401 

By  resolution  of  the  or-amido  acid  from  fermentation  caproic 
acid  by  means  of  Penicillium  glaucum,  Schulze  obtained  an 
active  leucin,  different  from  the  ordinary  leucin,  and  which 
was  left  rotating  in  hydrochloric  acid  :  ~ 

Acid  ...     c  =  4  to  5,     [a]  D  =   -  26.0°  to  —  26.5° 

/-LEUCIN.  In  aqueous  solution,  left  rotating  ;3  in  acid  or 
alkaline  solution,  right  rotating. 

From  casein  : 

10  per  cent.  HC1 c  =  6.4        [>]/>  =  +  J7-540  V 

Alkaline <:  =  5-6  =  +    6.65     / 

From  beet  molasses  : 

4  per  cent.  XaOH £=2.371,  /  =  20°,  [a~]D  =  -f-  8.05°* 

From  conglutin  : 

19  per  cent.  HC1 c  —  5.00,     [a~\D  =  -f  17.31°  6 

20  per  cent.  HC1 c=  4-73,  =  +  I7-37 

RICINELAIDIC    ACID,     CH3(CH2)5CHOH.CH:CH.(CH.2X- 

COOH.     Melting-point,  53°. 

Acetone c  —  5  to  15,  [«-]  D  =  +  4.8  to  5.4°   )  8 

Alcohol £=12,  ^4-6.67°  / 

RICINOLEIC  ACID.     Isomeric  with  ricinelaidic  acid. 
Acetone c  =  4.8  to  21,  /==  22°,    [«]  D  = -f  6.27107.5°* 

RICINSTEAROLEIC  ACID,   Q.H^OH.COOH.    Melting-point, 
Acetone c  =  6.4,     [a]^  =  +  13.67°  9 

1  Schulze  and  Bosshard:  Ztschr.  physiol.  Chem.,  10,  143;  Schulze  and  I,ikiernik : 
Ber.  d.  chem.  Ges.,  24,  472. 

'-  Ber.  d.  chem.  Ges.,  26,  56. 
3  lyewkowitsch  :  Ibid.,  17,  1439. 

Mauthner  :  Ztschr.  physiol.  Chem.,  7,  222. 

Landolt :  Ber.  d.  chem.  Ges.,  27,  2838. 

Schulze  and  Bosshard  ;  Ztschr.  physiol.  Chem.,  9,  100. 

Schulze  :  Ber.  d.  chem.  Ges.,  26,  56. 

Walden  :  Ibid.,  27,  3471. 

Walden. 


520  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

</-MANDELIC  ACID,  CfiH3.CHOH.CO,H.  Melting-point, 
132.8°. 

By  resolution  of  the  inactive  acid  by  means  of  the  cincho- 
nine  salt  or  by  Penicilliuvi  glaucum} 

Water p  =  2.886,     d  =  1.0055,     \a\  =?  =  156.5?° 

Cinthonine  Salt. 
Chloroform  +  .alcohol p  —  1.944,      \a\^  —  —  153.91° 

On  the  resolution  of  mandelic  acid  see  papers  by  Rimbach,2 
and  by  McKenzie.3 

/-MANDELIC  ACID.  Melting-point,  132.8°.  From  amygdalin 
or  by  resolution  of  the  inactive  acid  (through  the  cinchonine 
salt  or  by  Saccharomyces  ellipsoideus  and  a  schizomycite).4 

The  specific  rotation  of  solutions  in  water  and  glacial  acetic 
acid  decreases  on  dilution  according  to  the  following  formulas  :5 

Water q        91  to  97,      |V)£  =    -  212.52 -r  0.5777  ? 

Glacial  acetic  acid q       82  to  97,  —  2O9-95  -f-  0.2714  q 

An  increase  in  temperature  of  10°  decreases  the  specific  rota- 
tion of  the  solution  by  about  5°. 

On  the  behavior  of  methoxy-,  ethoxy-,  and  propoxy-substi- 
tuted  /-mandelic  acid,  see  McKenzie.6 

/-Cinchonine  salt,  more  soluble  than  the  d-sa.lt. 

Alcohol  -f-  chloroform p  —-  1.946,     [fl'l^  —  -r  9I-64°  " 

Walden8  gives  the  following  constants  for  /-mandelic  acids 
and  its  derivatives. 

Free  acid  Acetone c  =  2.50,        [#]"  —  ~  148.0° 

(m.  p.  I3i°-i32°)  Water 2.45,  —153.06 

Amide                         Acetone 2.50,                         -    66.6 

(m.  p.i22°-i22.5°)Acetone 1.50,  —    66-7 

Methyl  ester              Carbon   disulphide-.  3.33,  -214.1 

(b.  p.  160°,  32mm.)   "                    "  1.67,  —217.0 

Acetone 3.33,  —  1 10. 2 

1  Lcwkowitsch  :  Ber.  d.  chem.  Ges.,  16,  1568. 

*  Ibid.,  33,  2385. 

*  J.Chem.  Soc.,  73,964. 

4  I.cwkowitsch  :  Ber.  d.  chem.  Ges.,  16,  1571- 

*  Ivewkowitsch  :  Ibib.,  16,  1567. 
«  J  Chem.  Soc.,  75,  753  (1899). 

7  lyewkowitsch :  Ber.  d.  chem.  Ges..  16,  is;j 
r.  phys.  Chem.,  17,  706  ff. 


ACIDS  WITH  THREE  ATOMS  OF  OXYGEN  521 

Ethyl  ester                 Superfused ^=1.1270,  -123.12 

(b. p.  1 50°, 2 1  mm.) Chloroform c  —  6.67,  [>]/>  =    -128.4 

(m.  p.  35    )                "                                        3-33,  -  I26-4 

Acetone 5.81,  -    90.62 

"      1.16,  -    87.1 

Carbon  disulphide ...            5.00,  -180.0 

"                "        ...            2.50,  —180.0 

"        ...           0.88,  -180.5 

Isobutyl  ester            Superfused d  —  1.0870,  -  100.73 

(b.  p.  159°,  19  mm. 

solid)                  Carbon  disulphide...    £  =  5.0,  —146.6 

"...            2.5,  -144.0 

j-Amyl  ester           b.p.  i66°-i67°,  17  mm.  d  =  1.0531,  [a~\D  -     -   96-46 

/-Amyl   ester             "     i66°-i67°,  17    "              1.0530,  "               -    94.02 
Acetylmandelic 

acid, methyl  ester     "    177°,           45    "                 -.1546,  "            —146.37 
Propionylmandelic 

acid, methyl  ester     "    184°,           45    "                1.1261,  "            —135-5 
Propionylmandelic 

acid,  ethyl  ester,  Superfused d  =.  1.0936,  — 113.7 

(b.  p.  1 77°, 30  mm.  Chloroform c  —  10.0  -no.8 

m.  p.  33C)                    "                                        5.0  -109.4 

Carbon    disulphide..              5.0  — 131.5 

"                         2.5  "            -126.8 
Valerylmandelic 

acid,  ethyl  ester,  b.p.  1 73°-i74°,  18  mm.  rf  =:    1.0544,     "  -    97.06 

Carbon  disulphide..    c  =  10.0,  —117.25 

"                          5.0,  —116.9 

Acetylmandelic  acid,  m. p.  56®.  Acetone-.               3.33,  —156.4 

In  addition  Walden1  gives  the  following  observations : 
^-PHENYLCHLORACETIC  ACID,   C6H5.CHC1.COOH.     From 
/-mandelic  acid.     Melting-point,  56°  to  58°. 

Benzene c  =  3.33,     [orj^^-f  132.13° 

"      5-33,  4-I3I.6 

Carbon  disulphide 4.00,  -f  131 .3 

Chloroform 5.33,  4-107.9 

Chloride,  liquid. 

b.  p.  I20J  (23mm.)     Carbon  disulphide  c  —  6.0,        \_<*\D  ==  ~^  I5^-33° 
Methyl  ester,  liquid 

b.  p.   i35°-i36°(22mm.)  d  =  1.2087  +107.55 

Ethyl  ester,  liquid 

b.  p.  162°  (45  mm.)  rff  =  i.i594,  +    25.19 

In  carbon  disulphide,  p  =  4.96,     d  =  1.2527,  -}-    26.39 

«-Propyl  ester,    b.  p.  180°,  60  mm.  1.1278,  +    23.94 

1  Ztschr.  phys.  Chem.,  17,  714  ;  Ber.  d.  chem.  Ges.,  28,  1295. 


522  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

i-Amyl  ester,          "     i67°-i68°,  20  mm.    rf=  1.0828,    [>]/>    ^.  +  23.31 
/-Amyl  ester,          "     i69°-i7O°,  24  "  1.0826,  -f  26.79 

</-PHENYLBROMACETIC  ACID,  C6H..CHBr.CO,H.  From 
/-mandelic  acid.  Melting-point,  76°  to  78°. 

Benzene c  =  8.0,     \_(X~\D  —  +  45-4°. 

Bromide,       liquid,    b.p.  I45°-I47C,  24  mm  d™  —  1.853,     [#]  D  =  -f  44-53° 
Methyl  ester,       "         "172°,  53  M42I,  +29.82 

Ethyl  ester,          "         "   164°,  20     "  1-3893,  +16.56 

Isobutyl  ester,     "         "  i67°-i68°,  19     "  1.2892,  +    9.77. 

^-ISOPROPYLPHENYLCHLORACETIC    ACID,  C3H..C6H4.CHC1. 

CO2H.     Melting-point,  75°  to  76°. 

Benzene £=--3-0,      [«]„       +23.3°. 

^-ISOPROPYLPHENYLGLYCOLUC    ACID,      C;tH7.C6H4.CHOH. 

CO.H.1 

By  crystallization  of  the  cinchonine  salt  of  the  inactive  acid. 
Melting-point,  153°  to  154°. 

Alcohol £  =  4.0568,  /  ,17°,  \a\D  =  +  134-9° • 

Quinine  salt.  m.  p.  I92°-I93°.2 

Alcohol £  =  0.9248,  /  -24°,  79-4°- 

Cinchonine  salt.  m.  p.  201°. - 

Alcohol r— 2.3014,     /=:i3°,  +136.8°. 

/-ISOPROPYLPHENYLGLYCOLLic  ACID.  By  crystallization  of 
the  quinine  salt  of  the  inactive  acid.2  Melting-point,  153°  to 
154°. 

Alcohol £^4.0916,     /-I7°,     [«]/>-    -135°. 

Quinine  salt.     m.  p.  204° -205°. 2 

Alcohol £  =  0.3800,     /=I3°,  -118.4° 

Cinchonine  salt.     m.  p.  167°.'- 

Alcohol £=1.3308,     t ---  24°,  +    83.4° 

^/-TROPIC  ACID,  C,H5.CH(CH2OH).CO2H.  Melting-point, 
127°  to  128°,  [<x\D  =•  -h  71.4.  Solvent  and  concentration  not 
given.3 

/-TROPIC  ACID.     Melting-point,  123°,  [a]D  -     -65.2°.^ 

1  Pileti :  J.  prakt.  Chem.,  [a],  46,  561  ;  Gazz.  chim.  ital.,  aa,  2,  395. 

»  Fileti  :  Loc.  cit. 

*  I^adcnburg  and  Hundt :  Ber.  d.  chem.  Ges.,  aa,  2591. 


ACIDS  WITH  FOUR  ATOMS  OF  OXYGEN 


523 


9.  Acids  with  Four  Atoms  of  Oxygen  and  Derivatives 


ACID,  CH,OH.CH.OH.CO2H. 

The  racemic  acid  obtained  by  oxidation  of  glycerol  with 
nitric  acid  has  been  resolved  by  means  of  Penicillium  glaucum* 
and  Bacillus  ethaceticus?  In  the  first  case,  the  left-rotating 
acid  remains  un  attacked,  and  the  right-rotating  in  the  second 
case. 

Here,  as  with  the  lactic  acids,   the  rotation  determinations 
are  inaccurate,  because  on  evaporation  of  the  aqueous  solutions 
a  change  into  a  left-rotating  anhydride  seems  to  take  place  : 
c  —  20,  acid  (calcium  salt  and  oxalic  acid),  f«l^=  ~h  2.14°.  3 

Salts  of  the  d-Acid.     Left  rotating. 

Detailed  observations  have  been  made  by  Franklaud  and 
Appleyard,4  who  give  the  following  figures  : 


Formula. 

c. 

t°. 

M* 

hydrated 
salt. 

anhydrous 
salt. 

I  iCC  H  O  }  .  . 

10 
10 

"•635 
io.359 
10.610 

10 
10 
10 
10 
10 
10 

II 

12 

18 

!8 
20 
17 
15 

19 

16 

19 

-11.66 
—  I0.o8 

20  66° 

Na(C  H  O  ^        'HO.. 

-  16.13 
16  46 

K7O  H  O  ^ 

KfCHO  VCHO  \.  . 

9.24 
18  o^ 

NH  (C  H  O  xi 

Oaf  C  H  O  ^      i-  -2H  O 

Sr(  C  H  O  ^     -4-  7H  O  .  . 

Jo-o4 
-  11.91 
IO  OI 

BafC  H  O  "l          2H  O 

Mg(C3H504)2        H20  
7n(C  HO1!    -     HO. 

y-w 

-  18.65 
-22.18 
—14.11 

-  20.08 

-  23.63 
-  15.29 

Cd(C3H504)2       I'^O  

Esters  of  the  d-Acid.     Left  rotating. 

Frankland  and  MacGregor5  have  investigated  the  following 
liquid  esters  : 

1  I,ewkowitsch  :  Her.  d.  chem.  Ges.,  16,  3720. 
3  Frankland  and  Frew  :  J.  Chem.  Soc.,  59,  96. 
3  Frankland  and  Frew  :  Ibid.,  59,  101. 
*  J.  Chem.  Soc.,  63,  296. 
•"•  Ibid.,  63,  511, 1410. 


524 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Methyl  ester d£ 

Ethyl  ester 

7V-Propyl   ester 

Isopropyl   ester 

yV-Butyl  ester 

Isobutyl  ester 

Sec-Euty\  ester • 

Heptyl  ester 

Octvl  ester 


.2798, 
.1921, 
.1448, 

•I3°3, 
.1084, 
.1051, 
.1052, 
.0390, 
.0263, 


15°, 
17°, 

I7°! 

i8c-i9.5c, 
19°, 
18°, 

19°, 


-    9.18 

-  12.94 

-  11.82 

-  14-23 

-  10.58 

-  11.30 

—  IO.22 


On  amyl  esters  of  af-glyceric  acid,  see  Frankland  and  Price.1 

Esters  of  d'-diacetylglyceric  acid  were  tested  by  Frankland 
and  MacGregor.- 

See  also  the  following  papers  : 

Ethereal  salts  of  active  and  inactive  monobenzoyl-,  dibenzoyl-, 
diphenylacetyl-,  and  dipropionylglyceric  acids.3 

Effect  of  the  mono-,  di-,  and  trichloracetyl  groups  on  the 
rotatory  power  of  methylic  and  ethylic  glycerates  and  tartrates.4 

Frankland  and  Aston5  give  the  following  values  for  the 
specific  rotation  of  the  methyl  and  ethyl  esters  of  ditoluyl 
glyceric  acid. 


MS. 

MS". 

\lctliyl  diparHtoluyl  jjlycera.te  

_|_   Al   21° 

+  25  OQ° 

+  42  41 

+  26  18 

_|_  26  6? 

!     17  4"* 

_j_   26  O8 

_L-   l8  O^ 

Methyl  ditnetatoluyl  glycerate  

-f  26.40 

4-  26  80 

+  16.45 

+   1  7  4O 

Methyl  diorthotoluyl  glycerate  
Ethyl  diorthotoluyl  glycerate  

+   20.19 
+21.64 

+   13.08 
+  13.80 

PHENYLDiCHLORPROPiONicAciD  (cinnamic  acid  dichloride), 
C,H6.CHC1— CHC1.CO2H.     Resolved  by  aid  of  strychnine. 

rf-Acid,  [«]/>=:  +  66.5°. 

Methyl   ester  :  Alcohol [a]  D  =  +  61.9° 

Ethyl  ester  :  Alcohol +64.1 

»  J.  Chem.  Soc.,  71,  253. 

2  Ibid.,  63,  1419. 

3  Frankland  and  MacGregor:    /bid.,  69,  104  (1896). 
«  Prankland  and  Patterson  :  Ibid.,  73,  181  (1898). 

Ibid.,.,  75,  493  (1899). 


ACIDS  WITH  FOUR  ATOMS  OF  OXYGEN  525 

/-Acid,  [«]„  =     -  65.9°.  ' 

The  following  compounds  may  also  find  a  place  here  : 
(/?)-TYROSIN.    C6Hi(OH)CH.NH,.CO2H.       Melting-point, 
235°  (Lippmantr)  ;  290°  (Erlenmeyer  and  Lippmann3). 
Rotation  in  aqueous  solution  in  presence  of  acid  or  alkali. 

From  silk  : 

21  per  cent.  HC1  •  =    4-5*,  t  --=  16.2°,  [«]  D  =   -  7.98°  * 

1  1.  6  per  cent.  KOH  .........  5.8,  20.5,                        —9.01 

1  1.  6  per  cent.  KOH  .........  11.51,  16.1,                       -8.86 

From  beet  molasses  : 
21  per  cent  HC1  .............   C     :    3.92,     /  =  20°,       [«]/>  =    -  8.oyc  5 

From  conglutin  : 
21  per  cent.  HC1 
4  per  cent.  HC1 

A  right-rotating  tyrosin  is  known,  [a~]D=  -f-  6.85,  ;  but 
whether  or  not  this  is  a  position  isomer  has  not  been  deter- 
mined. 

CYSTIN  (SC(CH3)(NH,)(COOH))2. 

Dissolved  in  ammonia  ........  P  ~~  J-OS1)      \_°^\j  ~    —  141.1°  ! 

Dilute  hydrochloric  acid  .....   c  —  0.8  to  2,  r«]Zj=  —  205.86°  9 

Dilute  hydrochloric  acid  .....  c  =  2.13,  —  214°  10 

Derivatives  : 

Bromphenylmercapturic  Acid, 

CH,.CONH.C(SC6H4Br)(CH3).COOH. 
Alcohol  ..................  p  •=  12  to  15,     \_a~\D  =    ^6.7 

Dilute  NaOH  .............  25,  -f  6.4 

PhenylmercapturicAdd,  CH3CONH.C(SC6H5)  (CH3)COOH. 


Na  Salt,  CH3CONH.C(SC6H5)(CH3)COONa. 
Alkaline  solution  ..........  p  =  8,       [o-]^  =  +  4 

Finkenbeiuer  :  Ber.  d.  chem.  Ges.,  27,  889. 
Ibid.,  17,  2837. 

Ann.  Chem.  (Mebig),  219,  173. 
Mauthner  :  Monatsh.  Chem.,  3,  343. 
I^andolt  :  Ber.  d.  chem.  Ges.,  17,  2838. 
Schulze  and  Bosshard  :  Ztschr.  physiol.  Chem.,  9,  98. 
lyippmann  :  Ber.  d.  chem.  Ges.,  17,  2839. 

Kiilz  :  Ztschr.  fur  Biologic  by  Kiihne  and  Voit,  20  [N.  F.  2],  9. 
Mauthner  :  Ztschr.  physiol.  Chem.,  7,  225. 
1C  Baumann  :  Ibid.,  8,  305. 


5*6 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Bromphenylcy stein,  (NH,) ( CH:J)C(SC6H4Br)COOH. 

Dilute  NaOH p  =  9,       [<]/>=  ~  3-7°  ! 

10.  Acids  with  Five  Atoms  of  Oxygen 
Malic  Adds,  CO,H.CH.OH.CH.,.CO2H. 

NATURAL  MALIC  ACID,  commonly  known  as  /-malic  acid. 
This  was  first  investigated  by  Pasteur  in  aqueous  solution  and 
found  to  be  left  rotating.  Later  investigations  by  Schneider' 
showed  that  the  left  rotation  decreases  with  increasing  con- 
centration, that  inactivity  is  reached  with/>  —  34.24,  and  that 
then  right  rotation  follows.  The  dependence  of  the  specific 
rotation  on  the  percentage  amount  of  water  in  the  solution  q 
is  shown  by  the  formula, 

O]#     ~  5-891  —  0.08959  q  (q  =a  30  to  92), 

which  gives,  for  example,  the  following  values  : 


Q- 

P- 

Ms- 

9- 

P- 

Ms. 

30 

70 

4-  3-203° 

70 

30 

-  o.38oc 

40 

60 

i  2.307 

80 

20 

1.276 

50 

50 

+  1.412 

90 

10 

-  2.172 

60 

40 

+  0.516 

95 

5 

-  2.620 

According  to  the  above  formula,  the  anhydrous  malic  acid 
must  have  the  rotation,  [a]D-.  -\-  5.89,  and  the  substance 
must,  therefore,  be  considered  as  right  rotating.  As  shown  in 
§63,  however,  the  right  rotation  may  possibly  depend  on  the 
formation  of  crystal  molecules,  and  as  the  ordinary  acid  shows 
left  rotation  in  other  liquids  besides  water,  acetone  and  methyl 
alcohol  for  example,  it  is  advisable  to  retain  the  old  designation 
of  /-malic  acid  to  avoid  misunderstanding. 

The  right  rotation  of  concentrated  solutions  is  diminished 
by  increase  of  temperature,  but  the  left  rotation  of  dilute  solu- 
tions, on  the  other  hand,  is  increased.  A  solution  with  per- 
centage strength/ —  28.67  is  rignt  rotating  below  15°,  but 
left  rotating  above.  For  further  details  see  §60. 

On  the  rotation  dispersion  of  malic  acid  see  §46. 

1  Baumann  :  Ber.  d.  chera.  Ges.,  15,  1731. 

-  Ann.  chim.  phys.,  [3],  31,  81. 

*  Ann.  Chem.  (Iyiehig),  307,  261. 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN 


527 


For  the  rotation  of  solutions  in  acetone  and  methyl  alcohol, 
Walden1  found  : 


Acetone 

Methyl  alcohol 


^=13-3,     [«].,,        -5-oto  — 5.34' 
30,  -  2.78 


Influence  of  Sulphuric  Acid  and  Acetic  Acid  on  the  Rotating 
Power  of  I- Malic  Acid. — According  to  the  experiments  of 
Schneider,1'  the  left  rotation  of  dilute  solutions  of  malic  acid  is 
decreased  by  addition  of  increasing  amounts  of  the  acids  named, 
and  after  passing  a  point  of  inactivity,  an  increasing  right 
rotation  follows.  The  following  figures  were  obtained,  which 
are  given  in  connection  with  the  value  of  [«]/>  for  the  pure 
aqueous  solutions  : 

I.  SULPHURIC  ACID. 


Composition    of    the 

solutions  in 

' 

1 

per  cent,  by  weight. 

Mol.  H2SO4  to  i           Found, 
mol.  C4H6O5             r/vl20 
-r  loo  mol.  HoO.          L"J^- 

M* 

without 
H2S04. 

C4H605. 

H«0. 

H2S04. 

' 

6.76 

90.77 

2-47 

\ 

-  1-33° 

—  2.46 

6.59 

88.58 

4.82 

I 

—  0.76   ;  -  2.48 

6.44 

86.50 

7.06 

\\ 

—  O.2O 

-  2.49 

6.29             84.51 

9.20 

2 

+  0.21          —  2.50 

6.15             82.61 

11.24 

A 

0.84 

—  2.52 

II.  ACETIC  ACID. 


Composition    of    the  solutions  in 
per  cent,  by  weight 

Mol.   C»H4Oo  to  i 
mol.  C4H6O5 
+  50  mol.  H2O. 

Found 

Ms. 

[«> 

without 
C2H402. 

C4H605. 

H,(  )                     QjH4O2. 

10.04             67.47 

22.49 

5 

-•1.35- 

-2.17° 

8.20            55.08 

36.72 

10 

-0.57 

-2.33 

6.00 

40.29 

53-71 

20 

0.13 

-2.53 

5-29 

35.52 

59-19 

25 

+  0.14       -2.59 

Rotation  without  Addition  of  a  Solvent. — From  the  formula 
of  Schneider,  above,  which  shows  the  dependence  of  the 
specific  rotation  of  aqueous  solutions  of  malic  acid  on  the  con- 
centration, it  follows  that  the  acid  must  be  right  rotating  in 


1  Ber.  d.  chem.  Ges.,  29,  137. 
-  Ann.  Chem.  (Liebig),  207,  279. 


528  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

anhydrous  condition,    and   show   [«]p  =  :  +  5.89°  at  a  tem- 
perature of  20°. 

Walden1  has  been  successful  in  observing  this  right  rotation 
by  rapidly  melting  the  acid  at  a  temperature  of  100°  to  110° 
and  pouring  it  into  a  glass  trough  with  parallel  end  surfaces. 
In  the  hot  condition  the  liquid  mass  rotated  to  the  left,  but 
after  cooling,  the  rotation  was  to  the  right.  The  following 
rotations,  referred  to  a  layer  i  dm.  in  thickness,  were  found  by 
the  Landolt  ray  filter  method. 

Temperature. 

90°-95°  17°  "^ 

a  for  Red —4-4°  +3-5° 

Yellow  (D) —5-5°  +5-2° 

Green —  6.  i°  +  6.8° 

Light  blue 7.0°  -f  7.7° 

The  fused  mass  when  dissolved  in  acetone  exhibits  left 
rotation,  and  the  more  strongly,  the  longer  the  heating  was 
continued  ([>]/>  =  -  8°  to  —  16°).  This  shows  the  begin- 
ning of  anhydride  formation. 

Alteration  in  the  Acid  on  Heating. — As  Walden- found,  malic 
acid,  when  heated  in  the  dry  condition  to  100°  for  twenty-four 
hours,  or  when  heated  through  a  shorter  time  to  165°  in  vacuo, 
is  converted  into  a  tribasic  anhydro  acid,  C8H10O9,  while  at  a 
higher  temperature  (i8o°),a  dibasic  acid,  C8H^O8,  is  formed. 
The  two  anhydrides  show  strong  left  rotation  when  dis- 
solved in  acetone,  amounting  to  [<*]/>  -  19  to  — »  25°,  while 
the  original  acid  shows  [#]/>  =  —  6°  to  —  7°. 

Rotation  of  Malic  Acid  in  Different  Solvents. — Experiments 
on  this  point  have  been  made  by  Nasini  and  Geunari3  and 
also,  especially,  by  Walden.4  By  help  of  ray  filters,  the  latter 
found  the  following  specific  rotations,  from  which  the  corre- 
sponding dispersion  coefficients,  DC,  referred  to  [«]red=  i» 
were  derived.  All  the  values  obtain  for  a  temperature  of  18°. 
As  usual,  c  is  the  number  of  grams  of  malic  acid  in  100  cc.  of 
solution. 

1  Ber.  d.  chetn.  Ges.,  33,  2849  (1899). 

-  Ibid.,  Ja,  2706  (1899). 

*  Ztechr.  phys.  Chein.,  19,  117. 

4  Ber.  d.  chem.  Ges.,  33,  2856  (1899). 


ACIDS  WITH   FIVK  ATOMS  OF  OXYGEN 


529 


It  was  found  that  the  rotating  power  of  /-malic  acid  is  sub- 
ject to  extremely  great  variations. 


Solvent. 

Benxyl 

alcohol. 

i  vol.  benzyl  alcohol, 
i  vol.  benzene. 

3  vols.  benzyl  alco- 
hol, 2  vols.  carbon 
disulphide. 

* 

12. 

6. 

4.8. 

[a]  Red  

2.7° 

He        I 

1-3° 

£>c  =  i 

^3  Dc=  i 

Yellow  /;.  -- 

4.0 

i-5 

2.5 

+  3-4                1.9 

Green  

5.5 

2.0 

+  4-75 

3-7 

+  4-4                2.5 

Light  blue- 

7-7 

2.85 

+  6.75 

5-2 

-   6.5               3-6 

Dark  blue.  - 

II.  0 

4.1 

+  9-7 

7-5 

4-  8.5               4-8 

In  the  above  cases,  the  /-malic  acid  exhibits  right  rotation 
with  strong  rotation  dispersion. 


Solvent. 


Cry st.  formic  acid. 


Acetone. 


c. 

7.66. 

38.3- 

23-7 

/  =  18°. 

t  23o° 

[a]  Red  . 

,    -0 

o  8° 

—  c  n°    Dr 

\  fi°    Dr 

Yellow  D- 

0-1 

-4-6 

-0.75 

—  6.0 

1.2 

-5-5 

1.2 

Green  

—  5-2 

-0.4 

-7-1 

1.42 

-6.7 

1-45 

Light  blue 

-5-9 

-r  0.6 

-7-5 

1.50 

—  7.0 

1-52 

In  these  solvents,  as  in  the  following,  the  acid  is  left-rotating. 
With  formic  acid  the  rotation  decreases  with  the  concentra- 
tion and  becomes  even  positive  for  the  blue  rays. 


Solvent. 

3  vols.  acetone,  2 
vols.  benzene. 

Phenyl-methyl 
ketone. 

;i  vol.  phenyl-methyl 
ketone,  i  vol. 
paraldehyde. 

c. 

9-44 

5- 

5- 

[a]  Red  •     .   • 

1  r>° 

i  6° 

1  0° 

Yellow  D. 

4.0 
-  4.1 

3-° 
-4.0 

J-«J 
-  3-o 

Green  

Light  blue 

-4.i 
-4.2 

—  4.0 
-4-6 

-3.0 
—  3-0 

In  the  above  liquids  we  notice  the  very  peculiar  phenom- 
enon that  the  rotation  is  nearly  the  same  for  all  rays.     Th« 
same  behavior    was     observed    by   Nasini    and   Gennari    for 
34 


530 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


aqueous    solutions  of  malic  acid  having  a  concentration  of 
c  =  8.48.' 


Solvent. 

i  vol.  acetone,  i  vol.  isobutyl 
alcohol. 

Isobutyl 
alcohol. 

i   vol.  formic 
acid,  i  vol.  ethyl 
acetate. 

r. 

11.8 

5. 

10. 

9.58. 

-5-8° 
-6.6 
-7-4 
-8.9 

DC. 

I 

1.14 
1.28 
1.50 

—  6.2° 

-6.3 
-8.4 
-8.5 
-8.6 

DC. 

•35 
•37 
•38 

-3-2° 

-3-7 
-4.1 

-4-4 
—  5.0 

DC: 

I 

1.16 
1.30 
1-37 
1.56 

DC. 
-   7.5°    i 

-      8.9           I.I9 
-       10.4       1.39 

-     12.0     1.  60 

Yellow  D. 
Green  
Light  blue 
Dark  blue  - 

In  the  above  solutions  the 
with  the  refrangibility  of  the 
consequence  is  but  weak. 


rotation  increases  but  slightly 
rays  ;  the  rotation  dispersion  in 


Solvent. 

i  vol.  acetone,  i  vol. 
paraldehyde. 

Acetaldehyde. 

Pyridine. 

c. 

1  1.  8. 

4- 

5- 

Red 

T  1   T  °     Dr  T 

?7   7°     Dr           T 

Yellow  D. 
Green  
Light  blue 

-17-6                   1.35 
-22.9                   1.75 
-27.5                     2.10 

—28.7                      1.  21 

-32.5                1-33 
-38.7                1.63 

—  30.0 
—  36.0 

1.30 
1-57 

These  three  liquids  which  are  able  to  act  chemically  on  the 
malic  acid  produce  a  very  strong  increase  in  the  left  rotation, 
while  the  dispersion  is  not  greatly  increased. 

A  substance  which  has  the  power  of  enormously  increasing 
the  activity  of  malic  acid  is,  as  Walden2  observed,  uranyl 
nitrate  with  simultaneous  addition  of  alkali.  The  specific 
rotation  with  this  addition  may  be  increased  to  158  times  that 
shown  by  a  pure  aqueous  solution  of  the  acid  of  the  same  con- 
centration. It  is  probable  that  the  high  rotation  corresponds 
to  the  alkali  salt  of  a  complex  uranyl  malic  acid.  Walden  has 
investigated  the  following  ten  mixtures  of  different  compo- 
sitions, in  which  it  is  seen  that  the  maximum  of  rotation  is 
found  in  solutions  Nos.  6  and  7.  These  correspond  to  a  relation 

i  Loc.  cit. 

1  Ber.  d.  chcm.  G«s.,  30,  2889  (1897). 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN 


531 


of  i  mol.  of  malic  acid,  4  mols.   of  potas^tum  hydroxide,   and 
i  to  4  mols.  of  uranyl  nitrate,  UO2(NO3)2-f  6H,O. 


No. 

In  100  cc.  aqueous  solution. 

<*D 

2  dm. 

M* 

Malic  acid. 
Grams. 

Potassium 
hydroxide. 
Grams. 

Uranyl 
nitrate. 
Grams.  . 

I 

0.65                     I.  08 

—  0.04° 

-      3° 

2 

0.65                      

10 

—  0.14 

ii 

3 

0.65 

0.27 

2 

-I.8o 

—  139 

4 

0.65 

0-54 

2 

-  3.60        |       —  277 

5 

0.65                     0.54 

10 

-3-13 

-  241 

6 

0.65                  i.c8 

3 

-6.17 

-475 

7 

0.65                  i.  08 

10 

—  6.09 

-470 

8 

0.65 

1.  08 

20 

-5.81 

-447 

9 

0.65 

1.  08 

34 

-5-43 

-415 

10 

0.65 

1.62 

10 

-5-86 

-451 

By  uranyl  acetate,  with  addition  of  alkali,  the  rotation  not 
only  of  malic  acid,  but  also  that  of  </-tartaric  acid,  ^-methyl 
tartrate,  /-quinic  acid,  and  /-mandelic  acid  is  greatly  increased, 
and  with  preservation  of  the  direction  of  rotation  of  aqueous 
solutions  of  these  substances.  On  the  other  hand,  uranyl 
acetate  produces  no  increase  in  activity  in  </-chlorsuccinic 
acid,  /-bromsuccinic  acid,  and  ^-amyl  acetic  acid.  The  action 
appears,  therefore,  only  when  the  acids  possess  a  free  hy- 
droxyl  group.1 

Salts  of  I- Malic  Acid 

The  specific  rotation  of  aqueous  solutions  of  these  has  been 
investigated  by  G.  Schneider. 2    He  gives  the  following  formulas 
for  the  relation  of  the  specific  rotation  to  the  percentage  con- 
tent of  water  q  holding  for  the  temperature  of  20°. 
KH.C4H405    ?  =  73-9o,      [<x]D  =  - 


K2. 

38-90, 

NaH.       " 

39-8o, 

Na,. 

34-94, 

LiH. 

50-90, 

Li,. 

60-94, 

XH4H.     ' 

72-94, 

<NH4)t.  " 

37-83, 

—  0.05562  0 
3.016    —0.1588    0  +  0.00055550* 
9.367    —0.2791     0  +  0.001152   02 
15.202  — 0.3322    0  +  0.00081840* 

8.572  —  0.3573    0  +  0.001868   02 
26.717  — 0.6821     0+0.002878   02 

3-955  —0.02879  q 

3-3I5  —0.0050420— 0.00051150* 


1  Walden  :  Ber.  d.  chem.  Ges.,  30,  2889  (1897). 

2  'Ann.  Chem.  (I,iebig),  207,  266  to  277. 


532 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


The  specific  rotations  for  a  number  of  solutions  are  accord- 
ingly : 


p 

9- 

KH. 

K.. 

Nan. 

Nas. 

UH. 

u. 

NH4H. 

(NH4)2. 

fin 

2  Ad° 

-I-  o  o^° 

J.     7  22° 

A    71° 

4U 

.    •        • 

•^•40 

T    3'** 

4'34 

5^ 

50 

.... 

-3-59 

-  I-7I 

-f  0.64 

-  4-62° 



.... 

-4.85 

40 

60 



4-51 

-3.23 

-1.78 

-6.14 

-  3.850 

— 

-5.46 

:>o 

70 

-  4-53° 

-5.38 

-4-53 

-4.04 

-7-29 

-  6.93 

-  5.97° 

-6.17 

2o 

so 

-5.08 

-6.13 

-5-59 

—  6.14 

-8.06 

-  9-43 

-  6.26 

-6.99 

10 

90 

-5.64 

-6.78 

.... 

—  8.07 

-8.45 

-11.36 

-6.55 

On  the  inactivity  point  in  the  concentration,  see  §57.* 

For  dilute  solutions  of  salts  of  malic  acid  see  §61 . 

A  series  of  observations  on  the  specific  rotation  of  neutral 
sodium  malate  has  been  carried  out  by  Th.  Thomsen.'2  Accord- 
ing to  these  experiments  the  point  of  inactivity  is  found  for  a 
strength  of  45.63  per  cent,  of  the  salt. 

Through  the  presence  of  free  alkalies,  the  rotation  of  the 
malates  is  displaced  in  the  direction,  left  to  right,  that  is,  the 
action  follows  in  the  same  direction  as  with  addition  of  free 
acids.  The  following  experiments  by  Thomsen3  show  the  ex- 
tent of  the  change  : 


p. 

28.93 
19.23 
10.94 

Ms 

Amount   of 
change. 

Of  the  pure 
Na2C4H405. 

After  addition 
of  i  mol.  NaOH 
to  i  mol.  salt. 

—  4.02° 
-6.3I 
—  7.90* 

+  0.37° 

-4-05 
-6.56 

4-39° 
2.26 

1-34 

1  In  using  the  interpolation  formula  with  three  constants,  the  composition  of  the 
solution  with  which  inactivity  must  appear,   is  most  easily  found  by  bringing  the 

Ft  n  A 


equation  A  -f  Bq  -f  Cq*  —  o  into  the  form  g*  -f  — ?  = , 

two  trigonometric  formulas : 

C        I-A 


and   then    applying  the 


tan 


1  J.  prakt.  Chem.,  [2],  35,  153. 

»  Lof.  til. 

4  Calculated  from  Schneider's  formula. 


-v: 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN 


533 


Of  the  pure 

Na,C4H,0, 


Amouut  of 
change. 


27.23         -4-84° 

i8.7i        -6.39 

9.38        -8.19! 


f  10.74° 
-L     i-99 
-    5-09 


15.58° 
8.38 
3-10 


The  alteration  increases,  therefore,  with  the  amount  of  free 
alkali  added,  and  is  the  greater  the  stronger  the  solution  is. 
Solutions  which  are  originally  left  rotating  become  in  this 
way,  easily,  right  rotating. 

The  influence  of  temperature  on  the  specific  rotation  of  the 
malates  is  shown,  as  with  the  free  acid,  in  displacing  the  rota- 
tion in  the  direction  right  to  left  for  increase  in  temperature. 
Th.  Thomsen2  has  noted  the  change  for  the  following  salts : 


K2C4H405. 

Na2C4H405. 

M.at 

[>]z,at 

p. 

10°. 

20°. 

30°. 

A 

10°.                       20°  ' 

30°. 

33-86 

-  4.48° 

-  5.22° 

-  5-85° 

42.75 

-     0.38°         -   0.89° 

-  2.04° 

23-25 

-5.18 

-5-90 

-6.57 

28.60 

-   3.41               -   4.52 

-5.58 

16.29 

5.62 

-6.35 

-  7-09 

19.51 

-   5-30            -  6.36 

-7.41 

14  46 

_   ^o                    _  o_ 

7  ofi 

' 

' 

4.994 

4.69° 


1.965 
-  2.58' 


Barium  Malate,  BaC4H4O5. 

p  -  9-383  8.505 

|>]-=  -f-8.i8°  +8.05° 

This  salt  is,  therefore,    right-rotating  down  to  a  strength  of 
the  solutions  of  about  3  per  cent.3 

Ammonium- Antimony  I    Malate,     NH4SbOC4H4O5,  shows  a 
very  high  specific  rotation  to  the  right  : 

Water.,  p  =  6.845,  t  =  17°,    [«]./  =  4-  "5.47,   [<X]D  =  +  102.64.°* 
i  Calculated  from  Schneider's  formula. 
•2  Ber.  d.  chem.  Ges.,  15,  443. 
:J  Schneider:  Ann.  Chem.  (I^iebig),  207,  277. 
4  Pasteur:  Ann.  chim.  phys.,  [3]  31,  85. 


534 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


For  the  action  of  alkali  molybdates  and  tungstates  on  malic 
acid,  see  §70,  p.  250. 

Esters  of  l-Malic  Acid 

Walden1  gives  the  following  constants  for  the  derivatives  of 
ordinary  malic  acid  : 


Boiling-point. 

mm. 

4T. 

[«]?. 

125° 
149 
152 
H7 
175 
191-192 
191-192 
230 
157 

H5 
162-163 
179 
145-147 

150 
150 
162-163 

174-175 
190-192 
140 
160 
158-160 
168 
182-183 

!95 
187-188 
182-184 
194-195 
178-182 
192-193 

195-197 
187-188 
188-190 
177-180 
(Chlorofc 
m.p.  156-158 

196  C, 
m.p.     196 
181 

"       207 
"  193-195 

10 

25 
10 

14 
15 

20 
20 
20 

35 
IO 

16 

20 

8 
9 

JO 
12 

16 

'3 

15 

10 
10 

17 

16 

37 
15 

22 
10 
17 
15 
12 
10 
12 

>rm,  c 
water 

H40, 

i      >  i 
<      t« 

1.2337 
1.1294 
1.4380 
1.0760 
1.0418 
1.0176 
1.0179 
0.9761 

1.1975 
1.1168 
1.0724 
1.0362 

1.1317 
1.0736 
1.0417 
1.0146 
1.1255 
1.0688 
1.1034 
1.0605 
i  .0263 
1.0045 
1.3062 
1.1566 
1.5072 
1.3936 
1.3150 

1.2022 
1.3325 
1.3059 
1.2850 

=  4-0) 

-  6.85° 

TO    iH 

-  11.62 
-  10.41 
-  11.14 
-    6.88 
-    9.92 
-    6.92 
-  22.92 
-  22.52 
—  22.85 
-  21.88 
-  22.94 

-   22.20 

-  22.44 

22.22 
—  22.40 
?T  68 

Dii«u~>VHitvl 

\\\_l  flTTlvl 

Dipthvl                    4< 

I  Methyl                      **            

Diethyl                     4i            

Dimethyl   isobutyrylmalate  

-  22.36 

Diethyl                     tk             

Dimethyl  isovalcrylmalate  

21.99 

Diethvl                           " 

22.39 

iMpropyl                  **               

-21.68 
-  19.91 

Diisobutyl                                

Dimethyl  chloracetylmalate  ••••••  • 

Dipropyl                                      

23.30 

Dimethyl   bromacetvlma.la.te  

*5-o* 

Diethyl 

*yy    1  *N 

Dipropvl                                      

22.24 

on  i^ 

Diethyl  a-bronipropionylmalate  .. 
Diethyl  <r-brombutyrylmalate  
Diethyl  <r  bromisobutyrylmalate  .. 
Dimethyl    nitromalate«  • 

20.30 
~  22.48 
-     24.76 
22.57 

-  18.80 
-37-6 
-38.0 
-  60.66 

»O  ££ 

Malic  acid  diatnicle  

,  t  —  4*oa 

f       8  fit: 

c  —  o.  75^1        ;>»•  "^ 

w^.w 

66    r 

C=  1.  00 

<          1.  00 

00.5 

—  70.0 

"         "    /^-naphtiniide 

5X.5 

•  Walden     /tschr.  phys.  Chem..  17,  248. 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN 

Anschiitz  and  Reitter1  find  : 


535 


Boiling-point 
at  12  mm. 

d?. 

M* 

Methyl  malate  

122° 

211J. 

—    688° 

Ethvl             '  '    . 

I2Q  2J-I2Q  6 

I28o 

—  TO  *\5 

I  ^O 

O7^6 

1  1  60 

WHntvl 

1  60  J.    I  7O  A. 

0-182 

IO  72 

ToSt 

22  86 

Fthyl                                       

jj  j  2—141  4 

•*V°o 

1  1  60 

22  60 

T  ^8  6    I  ^Q  2 

O72Q 

22  68 

0/170 

—  IQ  Q"% 

Purdie  and  Williamson2  have  obtained  nearly  the  same  re- 
sults for  some  of  these  esters. 

Frankland  and  Wharton3  have  made  the  following  determi- 
nations : 


Bp. 

mm. 

d'v 

t. 

Mi. 

Methyl 

benzoyl  ma 

late 

210-223° 

12 

1.2121 

21° 

-  5.62° 

Ethyl 

•• 

« 

210-220 

12 

I.I56I 

21             -  3.87 

Methyl  orthotoluyl 

malate..     214-225 

12 

I.I909         23             -  8.94 

Ethyl 

it 

215-225 

12            I.I39I         21             —6.25 

Methyl 

metatoluyl 

malate  •  • 

215-225 

12      '      I.I925         20 

—  6.34 

Ethyl 

•• 

"        ..;    212-220 

13            I.I37I         21             —4.67 

Methyl 

paratoluyl 

malate  •  •     200-225 

I3            I.I957         18.5 

-3.14 

Ethyl 



I.I382         20 

—  0.22 

The  densities  and  rotations  were  determined  for  a  wide 
range  of  temperatures  and  the  latter  were  found  to  vary  greatly 
with  the  temperature. 

d- MALIC  ACID.     Antimalic  acid. 

By  reduction  of  </-tartaric  acid  or  by  resolution  of  the  r-malic 
acid  from  racemic  acid  by  aid  of  cinchonine.4  Also  from 
</-asparagin  by  action  of  nitrous  acid.5 

d- Ammonium  Hydromalate. 

Water p  -=  8,     [a]/, -.---.-    6.3  (/-salt  [a]/,       —  6.2)6 

Ztschr.  phys.  Chem.,  16,  493. 

J.  Chem.  Soc.,  69,  830. 

Ibid.,  75,  337. 

Bremer  :  Her.  d.  chem.  Ges.,  8,  1594  ;  13,  351. 

Piutti  :  Ibid.,   19,   1693. 

Bremer  :  Lf>c.  cit. 


536  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

</-Malic  acid,  from  rf-chlorsuccinic  acid,  shows  according  to 
Walden  :' 

Acetone c       16,     [a] „  5.2° 

Methyl  alcohol c       30,  2.92 

</-METHOXYSUCCINIC  ACID,   CO,H.CH(O.CH3).CH2.CO,H. 

Crystals,  melting-point  88°  to  90°.  By  cinchonine  reso- 
lution of  the  r-acid  obtained  by  addition  of  methyl  alcohol  to 
fumaric  acid,2  or  by  strychnine  resolution/' 

Water £,11.208,  /  ^  18°,  !>]/>-=  +  33-3°°  )' 

11     f=     5.586,  /-=i8°,  =4-33.04) 

'•     c--~  24.65,  t--~  15°,  "      =  +  32.59 

11     ^^16.08,  /       14°,  ••      ^-  +  32.79 

"        C—      8.76,  t^   15°,  "          r   -]-  32.70 

Acetone c  -----  24.96,       /  —  11°,         "'  =          57.10 

•'      £^18.77,       t     -11°,         "      =  +  58.29 

M      c       10.30,      /=J4°,         "    -         58.03 

<  4-12,  t  14°,  "      =r    +    59.49 

c-     1.65,      /       14°,        "     =  +  60.09 

Ethyl  acetate c       20.54,       /  --  11°,         "    =-  --63.48 

"         r=  15.87,          /          12°,  M     -=  +  64.45 

"        C  8.92,         /=I2°,  "     -      •-     64.64 

Salts.—  In  the  following  data  by  Ptirdie  and  Marshall,  the 
concentrations  refer  to  the  anhydrous  salts  : 
Acid  Potassium  Salt,  crystalline.6 

Water c  =     4.010,     /  -.=  18.5°,     [«],,  -.      t    23.46° 

"      c-^    8.150,     /     :  18°,  "      ^  +  23.26 

Normal  Potassium  Salt,  crystalline/ 

Water £==    5.019,     /       14.5°,     [«]/>=+    9.36° 

*==  12.162,     /  -=  15.5°,         "      -+9-54 

Acid  Ammonium  Salt,  crystalline.* 

Water c  --    6.064,     t       M0,         [«]/>  -----    •    25.86° 

Normal  A miuon htm  Salt,  crystalline.'1 

Water c         2.823,     t  -    14°,         [a]/,  12.22° 

"      C     '    5-762,     /       14°,  =  +  12.32 

Her.  d.  chem.  Ges.,  39,  137. 

Purdie  and  Marshall :  ].  Chem.  Soc..  6j,  217. 

I'urdie  and  Bolain  :  Ibid.,  67,  946. 

I'tirdieand  Marshall. 

Purdie  and  Itolam. 

I'urdic  and  Marshall. 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN  537 

Calcium  Salt,  crystalline.1 

Water c         5.308,     /        18°,         |>]/>        -10.10° 

Barium  Salt,  C,H6O,.Ba  +  4H2O,  crystalline.1 

Water,  c       26.125  (anhydrous),  /  =  18°,  [or]"/)  -14.27° 

"        £-=12.416  /=i8°,  "    r  -    7.36 

"        c     -    5.746  /  —  18°,  "    =  -    2.21 

c=-    1.149            "  *—  18°,  "    -           3.16 

Cinchonine  Salt,  C-H>O-.C19H.,,N.)O.     Crystals,  melting-point 
171°  to  173°. 1 

Water c    -4,     '        17°,     [«]/>= -^-  154.89° 

Methyl  Ester,  d\*  —  1.1498,    \a]D  =     -f  52.51.'-' 

AMETHOXYSUCCINIC  ACID.     Crystals,  melting-point  89°. 

Water £  =  10.806,     /  =  18°,     [a~\D=  —  32.94°  J 

"    =s  —  32.70      ~)* 


Acetone ' c  —  25.588,  /=n°,  -56.25 

"     r=  15.614,  /  =  13°,  -58.18 

Ethyl  acetate ....  ^^=25.511,  /  —  11°,  -61.90 

"      ...r=  19.077,  /  -    13°,  "    =     -62.93 

Salts.1 

Acid  Potassium  Salt,  crystalline. 

Water c  =  4.046,     /  =  18°,  [a]i,=  -  23.59° 

"      ^^4.083,     /  =  i7-5,  -23.49 

Acid  Ammonium  Salt,  crystalline. 

Water c  =  8.774,     /  =  18°,  [0-1^^-25.85° 

Calcium  Salt,  crystalline. 

Water r  ^  5.482,     /  --=  13°,  [a]^^ -f-  10.03° 

"      c  =  2.210,     /=I4.5,  "  =  -|-    4.30 

Some  esters  have  been  investigated  by  Purdie  and  William- 
n.4 

Ethyl    ester a? J8  =  1.0705,     [»  —    —  50.11° 

Propyl  ester ^^5^1.0419,  —45.21 

jV-Butyl  ester dlt>  ~  1.0419,  —  41.63 

1  Purdie  and  Marshall. 

'-'  Purdie  and  Williamson  :  J.  Chein.  Soc.,  67,  971. 

1  Purdie  and  Bolam. 

4  J.  Chem.  Soc.,  67,  971. 


538  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


ACID,    CO,H.CH  (O.C2H5)  .CH2.C(XH. 
By  resolution  of  the  r-acid  by  Penicillium  glaucum?  or  with 
strychnine.8     Crystals,  melting-point  76°  to  80°. 

Water  .......  r=u.i7,          /=I7°,  [«]z>=  4-  33-02° 

.......  c=--    5.56,          /=I9>  "  =  +  32.54 

"       .......  c=-    8-22.5,      /  =  12-17,  "  =  +  34.4-34.7 

Chloroform  ..  t  =  11.61,         /  —  12,  "  =  +  47.75 

..  *=:    4.80,          /=I2,  "=-  +  45-55 

..   f  s:    4.52,  /=•  II,  f  44-17 

..  <:=:    i  .60,  *  =  ii,  "  =  +  39-4o 

Ethyl  alcohol  <:  =  11.81,  /  --  n,  "  =  +  60.57 

Ethyl  acetate  r  =    5-20,  t  •—  18,  "  =  +  69.9-70.5 

Acetone  .....  c  --    9.57,  /  =  14,  "  =  —  63.39 

"      .....  c=    3.83,  /==i4,                            -64.87 

"  .....     r=:       1.53,  ^=    M,  -    66.48 


y4«W  Potassium  Salt,  KC6H9O5  +  H,O,  crystalline.    Melting- 
point  1  60°. 
Water  .........   c  -  3.93  (contains  water)  ,     t  =  19°,     [a\D  —  +  26.49° 

Add  Ammonium  Salt,  NHtC6H9O3  +  H2O,  crystalline.4 

Water  .........   c    -  8.  13  (contains  water)  ,  t  =  15°,     [or]/?  =  +  28.65° 

11     .........  ^-4-59        "  *  =  i6,  =  +  29.08 

"     .........  6-  =  2.58        "  /=i7,  =  +  28.48 

Normal  Ammonium  Salt,  (NH4).,CfiH8O5,  crystalline. 
Water  ...........  £  —  5.22  (anhydrous),     /  =  14.5°,     [«]/>=+  18.29° 

''     ...........  <:=.-:  i.  48  /^i2,  =+18.93 

Calcium  Salt,  CaC4H8O5,  crystalline. 

Water  ..............  ^  =  3.04,     /  =  15°,     [a]/?~  -*-    8.39° 


Barium  Salt,  BaC6H8O5  (at  160°),  crystalline. 

Water  ..............   ^-4.56,     /  =  18°,     [«]/>-  +  6.37° 

"      ..............  c~  10.77,     /  —  18,  =  +  2.46 

"       ..............    ^^25.08,      is    19,  -4-37 

Estcn.* 

Methyl  ester  .............   rf»3  =  1.1055,     [>]/>  =  +  59-86° 

Ethyl  ester  ..............  ^  =  1.0418,  =  +  55-29 

Purdie  and  Walker  :  J.  Chem.  Soc.,  63,  229. 

Purdie  and  Williamson  :    Ibid.,   67,  963. 

Purdie  and  Walker  :  IMC.  cit. 

Purdie  and  Walker. 

Purdie  and  Williamson  :  J.  Chem.  Soc.,  07,  971. 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN  539 

/-ETHOXYSUCCINIC  ACID.     Solutions  in  water.1 

Acid  ammonium  salt p    =  2.5  \_OL\D—  —26.05°- 

Methyl   ester d™  —  1.0996,        "  —  60.92   ]  -1 

Propyl  ester d\    --1.0226,         "  —51.20 

^V-Butyl  ester d\     =1.0045,        "  —46.43 

Ethyl   ester ^»°  =  1:1045,        "  •    '-44  * 

Ethyl  Ethoxysuccinate.     See  Purdie  and  Pitkeathly." 

PROPOXYSUCCINIC  ACIDS,  CO,H.CH(O.C3H7).CH2.CO,H.' 

rf-Acid.     Water c       7.56,  t  =  12°,  |>]/>  =  -  36.04° 

rf-Acid,  potassium  salt. .  £  =  3.815,  /  =  18,  "  =  4-  32.30 

^/-Normal  salt £==  3.665,  /  =  18,  "  ==  -f  17.26 

"     £^1.833,  t  —  18,  "  =  -[-18.69 

/-Acid.     Water £  =  7.760,  /  =  12,  -  36.40 

"      £  =  3.104,  /  =  12,  —36-24 

/-  Acid.     Acetone r=  5.688,  /  =  12,  —  63.29 

"          £=2.275,       /  =  12,  -64.39 

/-Barium  salt.     Water.-  £  =  3.649,     /  =  18,  —  10.00 

"          "  "     ••  £=1.460,     /  =  18,  -10.45 

Propyl  Propoxysuccinate.     For  the   preparation  and   optical 
behavior  of  this  ester  see  Purdie  and  Lander.7 

^-CHLORSUCCINIC  ACID,  CO2H.CHC1.CH2.CO,H. 
From   ordinary  malic  acid  by  action  of   phosphorus  penta- 
chloride.     Melting-point  174°. 

1.  Water t  =  21°,         c=        16  6.4  3.2 

[ct]D^=  -f  20.6     —  20.8   -+-  21. 3° 8 

2.  Water c—    6.66     "    =  +  20.2^ 

Ethj-1  acetate c  =  10          "    =  +  52.70 

£=    6.66     "    =-^52.85 

Derivatives 


Anhydride,  CO  CHC1.CH2.CO.     Melting-point  80°. 

Ethyl  acetate c  =  10,     [»  =  -f  30.85  ) 

11       c=    5,      "    "   =  +  33-6oj 

Purdie  and  Walker  :  J.  Chem.  Soc.,  63,  238. 

Purdie  and  Walker. 

Purdie  and  Williamson  :  J.  Chem.  Soc.,  67,  972. 

Walden  :  Ztschr.  phys.  Chem.,  17,  252. 

J.  Chem.  Soc.,  75,  157. 

Purdie  and  Bolam  :  J.  Chem.  Soc.,  67,  949. 

J.  Chem.  Soc.,  73,  288  (1898). 

Walden  :  Ber.  d.  chem.  Ges.,  26,  225. 

Walden  :  Ztschr.  phys.  Chem.,  17,  253. 


540  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Chloride,  COC1.CHC1.CH2.COC1.    Boiling-point   91°  to  93' 
(iimm.),  d*'    •  --  1.5002,  |>]/,=:  +  29.53.' 


Dimethyl  ester..  B.  p.  114-115(170101.),  d?f  = 

Diethyl  ester "     130-131(20     "    ),  «'     = 

Dipropyl  ester ...     "         148      (20     "    ),  " 
Diisobutyl  ester.     "     162-164(17     "    ),  "     = 
Diamyl  ester "         190     (25     "    ),   "     = 


•  2555,  [«]/>=  4- 41- 42° 2 

•  1493,  ^7-5° 
.0925,    "    =+25.63 
.0524,    "    =  +  21.57 
.0319,    "    =  +  21.56 


/-CHLORSUCCINIC  ACID.  By  action  of  nitrosyl  chloride  on 
/-asparagin.  Melting-point  i740.n 

Water ^  =  9-3,     /  =  19°,     M/'  =    -19.67°. 

</-BROMSUCCINIC  ACID,  CO2H.CHBr.CHrCO2H. 

From  ordinary  malic  acid  and  phosphorus  pentabromide.* 

Dimethyl  ester...   B.  p.      129      (231001.  ),</=      ?      ,  [»=  +  50.83°  5 

Diethyl  ester "         143      (29     "    ),d=       ?      ,       "     =-(-40.96 

Dipropyl  ester. ..      "     153-154  (18  mm.),  d=  1.3010,      "     =  -j-  38.05  6 

/-BROMSUCCINIC  ACID.  By  action  of  nitrosyl  bromide  on 
/-asparagin.  Melting-point  i73°.7 

Ether ^=5.33,  [«]^=  —  67.92° 

Ethyl  acetate c  =  6.66  to  5.33,  =—72.71072.6 

Monamide,  CO,H.CHBr.CHrCONHa. 

Alcohol £  =  6.66,     [or]/?  =  — 67.12° 

Ethyl  acetate c  =  6.66,          "   =  —  67.57 

20  per  cent,  aqueous  H2SO4 c=  3.00,          "    =  —  44.3 

</-ASPARTIC  ACID,  CO,H.CH.2.CHNH.(.CO,H.  From  d- 
asparagin.  In  hydrochloric  acid  solution,  left  rotating. 

/-AsPARTic  ACID.     Ordinary  acid.     From  /-asparagin. 

i .  Solutions  in  water  are  right  rotating  at  the  ordinary  tem- 
perature, at  75°  inactive,  and  above  that,  increasingly  left 
rotating/  See  §60.  For  /=  20°  and  c=  0.5°,  [>]„  =  + 
4.36°.  Stated  earlier  by  Becker1  to  be  left  rotating. 

'  Walden  :  Loc.  cit. 

2  Walden  :  Loc.  cit.;  and  Ber.  d.  chem.  Ges.,  28,  1289. 

Tilden  and  Marshall  :  J.  Chem.  Soc.,  67,  494. 
*  Walden  :  Ber.  d.  chem.  (ies.,  28,  1290. 
i  Walden  :  IMC.  cit. 

6  Walden  :  Ztschr.  phys.  Chem.,  17,  254. 
'  Walden  :  Ber.  d.  chem.  Ges.,  a8,  2769. 
'  Cook  :  Ibid...  30,  204. 
b  Ibtd.,  14,  1035. 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN 


541 


2.  Solutions  in  aqueous  acids  exhibit  right  rotation.  *   Becker 

investigated  the  following  solutions  which  contained  : 
I 

FOR  i  MOL.  OF  ASPARTIC  ACID. 


i.      54  to  64  mol. 
water 
+  »  mol.  HC1 

[«]/>. 

2.       302  mol. 
water 
+  n  mol.  H2SO<. 

M*. 

n  —  i                     30.0° 

«  =  0-5 

+   21.8° 

1-5                      >2-6 

0.6 

+  24.2 

2                           ^3-4 

0-75 

-f  28.6 

3 

-f-  34-0 

i 

+  28.8 

\i 

+  33-9 
-34-0 

3 
5 

-f  31.5 
-f  32.0 

.... 

10 

—  33-5 

3.  Solutions  in  aqueous  alkalies  are  left  rotating.3  Becker* 
found  for  solutions  which  for  one  molecule  of  aspartic  acid  con- 
tained : 


b.  302  mol.  water  -f-     i 

"       "  "     +    3 

14       "  "     -f    5 

"      "  "    +  15-1 

"          "  "              20-2 


mol.    NH3  :  [V]=o 


—    9.2 
--    9-4 


"  "       =  —  12.1 

,  CONH2.CH2.CHNH2.CO2H. 

For  formation  see  Bischoff  and  Walden.  ' 

Water  ...........    [a]D  =  -f  5.41  (/-Asparagin  =  —  5.43)-6 

/-^8-AsPARAGiN.     Ordinary  asparagin. 

In  aqueous  and  alkaline  solutions,  left  rotating,  in  acid  solu 
tions  right  rotating.7 

The  following  determinations  were  all  made  by  Becker.1 
a.  Solutions  in  water  : 


p  =  0.705  d^1  =  i.ooio 
1.049  1.0025 
1.409  1.0043 

Pasteur:  Ann.  chim.  phys.,  [3],  31,  81  ;  34,  30. 

Ber.  d.  chem.  Ges.,  14,  1038. 

Pasteur :  Loc.  cit. 

Ber.  d.  chem.  Ges.,  14,  1037. 

"Handb.  d.  Stereochemie."  1894,  p.  220. 

Piutti  :  Ber.  d.  chem.  Ges.,  19,  1693. 

Pasteur  :  Ann.  chim.  phys.,  [3],  31,  75. 

Ber.  d.  chem.  Ges.,  14,  1030. 


-  5-95 
-5-42 
—  5-30 


542  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

b.  Solutions  in  dilute  acids  : 

TO  I  MOI,.  ASPARAGIN  -f-  300  MOI,.  WATER 


Mol.  HC1. 

Ms- 

Mol.  HjS04. 

Ms- 

Mol.  C2H4O2. 

MS. 

I 

+  26.4 

0-5 

+  23.1 

I 

-3.49 

1-5    !  +  30.4 

o.75 

+  27.3 

2 

-3-10 

2    ;  +  31-5 

i 

+  29.5 

5 

-i.45 

3 

4-31-9 

3 

-f  32.0 

7 

-0.59 

5 

-f-32-3 

5 

+  34.3 

10 

0.00 

10 

+  33-3 

10 

+  35-5 

15 

+  I.  II 

15 

+  33-7 

.. 



20 

+  2.63 

20 

4-34-3 

.... 

•• 

.... 

While  hydrochloric  and  sulphuric  acids  produce  strong 
right  rotation,  small  amounts  of  acetic  acid  produce  left  rota- 
tion. This  last  decreases  with  added  acid  and  is  finally 
changed  to  right  rotation.  That  the  addition  of  acetic  acid 
under  certain  conditions  of  concentration  may  cause  the  rota- 
ting power  of  asparagin  to  disappear  was  noticed  by  Champion 
and  Pellet.1 

c.  Solutions  in  dilute  sodium  hydroxide. 


In  100  parts  of  solution. 

Mol.  proportions. 

dy. 

Ms. 

Asparagin. 

NaOH. 

H20. 

Asparagin. 

NaOH. 

H20. 

10 

3 

87.0 

I 

I 

63-8 

1.0584 

-8.64 

10 

6.1 

83.9 

I 

2 

6l-5 

1.0915 

-6.69 

10 

9-1 

80.9 

I 

3 

593 

1.1232 

-6.35 

ACID,  C^2>CH.CH2.CH2.CO2H. 

Water c  =  2,  /  =  21°,     [a]/»=  +  10.2° 

"     <:  —  4   (supersaturated),     /  —  23,  "  =  +  10.6 

Dil.  nitric  acid c  —  4,  t  =  22,  "  =  -f-  29.9 

Calcium  Salt,  CaC5H7NO4.     Left  rotating. 

Water c  =  5.03,     /  ==  20°,     [a~\D=  -3-7° 

Hydrochloride,  C6H,NO4.HCL 

Water c  —  4,     /  =  21°,     (»=  +  20.4°- 

1  Compt  rend.,  8a,  819. 

*  Scheibler:  Ber.  d.  chem,  Ges.,  17,  1728. 


ACIDS  WITH  FIVE  ATOMS  OF  OXYGEN  543 

/-GLUTAMINIC  ACID.  From  the  racemic  acid  by  means  of 
Penidllium  glaucum.  In  100  cc.  9  grams  HC1  +  5  grams 
glutaminic  acid,  [<*]/>  -  -31.1.* 


flT-GLUTAMINE,    CQI  >CH  '  CHr  CH2'  CO' 

In  100  cc.  0.45  grams  H2SO4  -f  5     grams  glutamine,  [or]>  =  -f  30.0  2 

14  loo  "    0.3        "     H2C204  +  2.7       "  "  "  ==  -f  18.3 


^-PYROGLUTAMINIC  ACID,  c^     >CH.CH2.CH2.CO. 

Water  ...............   c  =  2.665,     *  =  25°,     [a]/,  =  -f  y03 

l-Acid  .................    \a\D  =  -  6.1  + 

SHIKIMIC  ACID,  C7H10O5.  Cyclic.  Needles.  Melting- 
point  184°.  The  following  observations  were  made  by  Eyk- 
man.5 

Water  ......  £  =  36.26,    [or]g  -    -  204.4°-,  *=  11.19,  [a\%=  -187.9° 

30-73,  -  201.5,  7-53  -  186.7 

21.71,  -  195-5,  5-93  -  184.7 

13.12,  -  190.0,  4.03  -  183.8 

From  which  is  calculated  :  [a],y  =   —  183.3  —  °-65  c 

Solutions  in  acetic  acid,  and  especially  in  50  per  cent,  sul- 
phuric acid,  exhibit  increasing  rotation  ;  but  tellurous  acid  de- 
creases the  rotation  in  marked  degree,  while  selenous  acid 
leaves  it  unchanged. 

Ammonium  Salt,  (NHjC.H9O5.     Rhombic  prisms. 
Water  ......................   £  =  32.00,     [<*]/>=   -189.7° 

5.23,  —172.1 

Triacetylshikimic  Add,  C.H7O5(C2HSO)3.     Amorphous. 
Absolute  alcohol  ............  c  =  5.496,     [<*]/>  =  —  170.0° 

"    ............  3-482,  -  169.6 

"    ............  I-45I,  -170.2 

Benzene  ....................  7.255,  —191.1 

"       ....................  4-230,  -  191-7 

....................  2.392,  -192.1 

Chloroform  .................  3.482,  —189.7 

.................  4-222,  -189.2 

1  Schulze  and  Bosshard  :  Ztschr.  physiol.  Chera.,  10,  143. 

2  Schulze  and  Bosshard  :  Ber.  d.  chem.  Ges.,  18,  390. 

3  Menozzi,  Appiani  :  Rend.  Ace.  I,inc.,  1893,  II,  421. 
*  Menozzi,  Appiani  :  Gaz.  chim.  ital.,  aa,  II,  105. 

5  Ber.  d.  chem.  Ges.,  34,  1278. 


544  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Tripropionylshikimic  Acid,   C7H7O5(C3H-O)3.      Amorphous. 

Absolute   alcohol c=  7.361,     [«]/>=  —  159.1° 

"     3-680,  -159-0 

Benzene 7.125,  -172.8 

"      5.36o,  -173-3 

Triisobutyrylshikimic  Acid,   C7H7O5(C4H7O)3.     Amorphous. 

Absolute   alcohol c  —  9.314,     [«]/>  =   -146.1° 

Benzene 7.247,  -157-9 

Shikimic   Acid  Bromide,  C-H9BrO5.     Hemimorphous,  hex- 
agonal needles.     Melting-point  235°   (uncorr.). 

Water c  —  8,     [a]/,  =  4   22° 

Hydroshikimic     Add,     C7HlaO:>.        Monosymmetric  prisms. 
Melting-point  175°  (uncorr.). 

Water  ..  p  =  16.515,  d**  =  1.054,  /  =  23°,   [or]/,       --  35.8° 

After   dilution    with   an  equal  volume  of   water,    [<*]/> 
-  18.2°. 

Hydroshikimic     Acid     Dibromide,     C7H10Br2O5.        Rhombic 
sphenoids. 

Water c  -.=  14.263,     t  ^  16°,     [a]D    --  58°  * 

"-ISOTRIOXYSTEARIC  ACID,  C17H32(OH)3COOH. 

Glacial  acetic  acid- . . .   c  --=  10  to  15,     [a]z>  -- --  —  6.25  to  6.0 a 

ii.  Acids  with  Six  Atoms  of  Oxygen 
For  the  aldehydes,  see  group  16  (oxyaldehydes,  sugars). 

; 

ARABONIC  ACID,  C5H10O6.     Left  rotating. 
In  solution  passes  gradually  into  the  lactone.     On  the  change 
in  rotation,  see  §75. 

Strontium  Salt,  Sr(C5H9O6)a  +  5H,O.     Crystals. 

Water  . .     c  =  4-353  (at  100°),     /  =  20°,     [or]z>^  -f-  1.96°  3 

Anhydride,  C5H8O5.     Crystals.     Melting-point  89°. 
Water...  [or]i>=  -63.37* 

Water.. .        p  =  9.45,  d™  =  1.0316,  /  »  20°,  [a\D--      -  73.9°* 
Kykman. 

Walden  :  Her.  d.  chem.  Ges.,  37,  3471. 
Allen  and  Tollens :  Ann.  Chem.  (I^iebig),  a6o,  313. 
Bauer  :  J.  prakt.  Chem.,  [a],  34,  47. 
Fischer,  Piloty  :  Ber.  d.  chem.  Ges.,  34,  4215. 
Fischer  and  Piloty. 


ACIDS  WITH  vSIX  ATOMS  OF  OXYGEN  545 

RIBONIC  ACID,  C5H10O,(. 

Cadmium  Salt,  Cd(C6H9Os)s  (at  100°).     Fine  needles. 
Water /   -20°,     [a]/,        ;    0.6°  [ 

Anhydride,  C5H8O5.     Crystals.     Melting-point  72°  to  76°. 

Water c   ----9.34°,     t  =  20°,     [«]/>  =   -i8.o02 

The  rotation  remained  twelve  hours  unchanged. 

XYLONIC  ACID,  C5H10O8.     See  §75. 

Strontium  Salt,  Sr(C5H9O6)2  +  6H2O.     Crystals. 

Water. ...  c  -^  4.305,  (at  100°),  t  =  20°,  [«]/,  =  +  12.14°  :t 
The  rotation  remained  constant. 
LYXONIC  ACID  I^ACTONE,  C5H8O5. 

Water  . .  p  —  9,783,  d  =  1.035,  /  =  20°,     [«]/,  =  -f  82.4°  * 

GLUCOSACCHARINIC  ACID  ANHYDRIDE,  SACCHARiN,C6H10O3. 
Made  from  dextrose  by  heating  with  lime.5  Rhombic  prisms. 
Melting-point  160°  to  161°. 

Water.-..  [«]/>=  +  93.i0(i 

Water..-.  /        12.077,  </'7.5-.-_-  1.0365,  /  =  17.5°,   [ 
Water....   c       4.257(100°),     /  =  20°,     [a]/,  -f  93.05° 
3-688      "      ,          "       ,  --93-" 

On  standing,  the  rotation  is  decreased  because  of  change  into 
the  acid.  See  §75.  The  rotation  diminishes  also  on  elevation 
of  temperature.9 

The  salts  rotate  to  the  left.  Scheibler  gives  for  the  sodium 
salt  [<*]/>  =  -  17.2°,  and  for  the  calcium  salt  [a~\D=  —5.7°. 

MALTOSACCHARINIC    ACID    ANHYDRIDE,    ISOSACCHARIN, 
CCH10O5.     Monoclinic  crystals.     Melting-point  95°. 
Water.,  p       9.471  (air  dry),    d*'  -•-  1.0302,  t—  20°,    [«]/)------ 61.88°  10 

Water.,  c       10  (air  dry),     t    =  10°,     [a]/>  =  -j-  62.97° ll 

Shows  no  multirotation. 

1  Fischer  and  Piloty. 
-  Fischer  and  Piloty  :  Loc.  cit. 
Allen  and  Tollens  :  Loc.  cit. 
4  Fischer,  Bromberg  :  Ber.  d.  chein.  r.es..  29,  583. 

•  Kiliani :  Ibid.,  15,  2954. 

6  Pel  i  got :  Conipt.  rend.,  90,  1141. 

'  Scheibler  :  Ber.  d.  chera.  Ges.,  13,  2216. 

-  Herrmann,  Tollens  :  Ibid.,  18,  1333. 

•'  Schnelle  and  Tollens  :  Ann.  Chem.  (I.iebig),  271,  66. 
111  Wehmer.  Tollens  :  Ib id.,  243,  323 
"  Schnelle  and  Tollens. 

35 


546  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

METASACCHARINIC    ACID  ANHYDRIDE,  METASACCHARIN. 
CSH,0O5.     Rhombic  crystals.     Melting-point  141  to  142°. 
Water p       7.846,  d  •-  1.026,  /        14°,   [«]/>         -  48.4°  ' 

7.o,         "  ~  46.96°  '-' 

Shows  no  multirotation. 

The  parasaccharinic  acid  of  Kiliani3  is  left  rotating. 

RHAMNONIC  ACID  (Isodulcitonic  acid),   C6H12OK.     See  $75. 

ISORHAMNONIC  ACID  LACTONE,  CBH10O-.  Melting-point 
150°  to  152°. 

Water p       8.903,     d       1.032,     [«]-;;  62.02°  4 

After  twenty-four  hours  by  change  into  the  acid,  [<*] 
—  5.21. 

DIGITALONIC  ACID,  CnH14O(i.  From  the  mixture  of  sugars 
which  result  from  the  resolution  of  pure  digitalin. 

Anhydride,   rhombic  crystals.     Melting-point  138°  to  139°. 
Water p       3.3327,  d       1.0084,  /       28°,   [a]/,        -  79.4°  * 

Tartaric  Acids,  CO.H.CHOH.CHOH.CO.H. 

</-TARTARIC  ACID. — The  following  formulas  have  been  given 
to  show  the  relation  of  the  specific  rotation  in  aqueous  solution 
to  the  concentration  c  or  to  the  percentage  strength  p  of  acid, 
or  finally  to  the  percentage  amount  of  water  q  in  the  solutions. 

i.  Arndtsen.6  Determined  by  the  Broch  method  for  dif- 
ferent Fraunhofer  lines. 

\oi\c  ^  +  2.748  n  0.09446  q 
\a\D—  -f  1.950  +  0.13030  q 


=  ^-0.153  +  0.17514  q 
=  —  0.832  -f  0.19147  q 


for  q       50  to  95, 

and  /  =  24°. 


[«]/•  3-598    i    0.23977  q 

OL  9.657  H    0.31437  q 

The  formula  for  [ar]  /,  according  to  Sonnenthal7  obtains  even 
for  a  0.2  per  cent,  solution. 

Kiliani':  Her.  d.  chem.  Ges.,  16,  2627. 
Schnelle  and  Tollens. 
Bcr.  d.  chem.  Ges.,  a6,  1649. 
Fischer,  Herhorn  :  Ibid.,  39,  1964. 
Kiliani  :  Ibid.,  35,  2116. 

Ann.  chiin.  phys.,  [.?],  54,  403;  PoKK.  Ann.,  105,  3t2. 
'  Wiener  Akad..  100,  Ahtli.  II  b,  s?^. 


TARTARIC    ACID  547 

2.  Hesse.1 

[a]/?  —  14.90  —  0.14  c  holds  for  c  —  5  to  15,     /     -15° 
15.11  —  0.14*:     4t         "  5  "   15,  20 

15.22  —  0.14^     "         "          5  "   15,  22.5, 

in  which  the  middle  formula  was  calculated  from  the  other  two. 

3.  Landolt.-' 

[«]/)•--   15.06  —  O.I3I  C,      C  —  0.5  tO  15,       /  :—  20° 

4.  Pribram.3 

[<X]D=  14-770  —  0.1321  /»,    p  =s  i  to  5,     /=  20° 

5.  Th.  Thomsen.4 

[a]/>  =  +  14.154  —  0.1644 p       p  —  20  to  50) 

-  2.286  J   0.1644  q        ^  =  soto8o) 
14.615  —  0.1588  p       p  =  20  to  50  ) 

1.265  —  0.1588^        ^  =  50  to  80) 

15.050  -  0.1535  P  P  =  20  tO  50 

-  0.300  -f  o.  1535  q        q  =  50  to  80 

-f   15.429  —  0.1480  /  /=  20  tO  50) 

0.629  4-  o.  1480  q    q  =  50  to  80  \ 
+  15.784  —  0.1429  p   p  =  20  to  50) 

1.494   0.1429^    ^  =  50  to  80  j 

From  these  constants  we  have  the  general  formula: 
[«]/>  =  (l3-°96  +  o.ii39/  —  0.00081  f2)  —  (0.1756  —  0.001135  t)P 

With  reference  to  the  concentration  c  we  have 

[or]/)  ==  13.436  —  0.1187  c ;  for  c  =-  22  to  63  and  /  =  20° 

The  value  of  the  specific  rotation  of  tartaric  acid  at  a  number 
of  different  temperatures  and  percentage  strengths  according 
to  the  Thomsen  formula,  is  shown  in  the  following  table. 

/=  10°  15°  20°  25°  30° 

/>       5<J,    O]/>=  +5-93  —6.69  4-7-38  ^-8.08  +8.64° 

40  7.58  8.28  8.91  9.55  10.07 

30  9.22  9.86  10.45  11.02  11.50 

20  10.87  11.45  11.98  12.49  I2-93 

On  the  variation  of  the  specific  rotation  of  aqueous  solutions 
of  tartaric  acid  with  the  temperature,  see  §60. 

1  Ann.  Chem.  (I^iebig),  176,  120. 
-  Ber.  d.  chem.  Ges.,  6,  1073. 

a  Math,  naturw.  Ahh.  d.  Berl.  Akad.,  1887,  p.  248. 
J.  prakt.  Chem.,  [2].  32,  213. 


548  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Salts  of  Dextrotartaric  Add 

On  the  rotation  of  tartrates  in  dilute  solutions,  see  §61. 
Potassium  Add  Tartrate,  KC4H5O,;. 

£  =  0.615,      t=^  20°,      [a]/,       22.61°  ' 

In  the  following  observations  by  Sonnenthal,'  T  is  the  time 
between  the  preparation  of  the  solution  and  the  observation. 


p. 

d-. 

T. 

[*}*• 

0.4116 

1.0044 

At  once  and  after  48  hours 

22.119° 

0.3001 

1.0041 

At  once 

20.  192 

0.2407 

I.OOII 

At  once 

22.241 

t  < 

" 

48  hours 

22.379 

(( 

it 

80  hours 

23.025 

120  hours 

23.025 

Sodium  Add  Tartrate,  NaC,H5O6  -f  H2O. 

i.  According  to  Thomsen3  the  specific  rotation  decreases 
with  decreasing  concentration,  but  increases  slightly  with  the 
temperature. 


Hydrate. 


L"J  r>  . 

L"J/>  •    I 

L"J  />  • 

L    J  '/' 

p. 

c. 

12.70 

13.50 

.... 

.... 

.... 

22.47 

10.  16 

10.65 

.... 

.... 

22.12 

22.19 

8.89 

9.26 

21.84 

21.85 

22.07 

7.62 

7.89 

21.85            21.88 

22.  IO 

22.29 

6-35 

6.54 

21.56            21.84 

21.77 

21.88 

2.  c==  4.409,    [or]2/,'  ==  23.95°   anhydrous  (21.67  hydrate)/ 
Lithium  Add  Tartrate,  LiC,H,(),.  +  H2O. 

Anhydrous /•       7.998.     [<r];°        27.43' 

Ammonium  Add  Tartrate,  NH4C4H5OH. 

Anhydrous t        1.712,      ['»];,'        25. 65° 4 

1  I<amlolt. 

D    Akail.,  100,  II,  510. 
a  Thomscn  :  J.  prakt.  Chem.,  [a|,  34,  NS. 
<   I.andolt. 


TARTARIC    ACID 


549 


Thallium  Add  Tartrate,  TlHC4H4O6. 

.*===!,       [a]*°          12.02°  j 

Potassium  Tartrate,  K,C4H4O6  -f  £  H2O. 

1.  Krecke2  found  for  the  hydrated  salt,  c  —  20  and  /  =  25° 
for  different  rays  : 

[a],  =  22.04,  [«V  =  26.84,    O!U  --32.95,   M*  =  34.96,  tar]  r  =  39-9*° 
The  influence  of  temperature  is  slight. 

2.  Anhydrous  c—  11.597,    [flr]/>=  28.48°  (hydrated  27.39). 3 

3.  Experiments  by  Schiitt4  gave  : 


Hydrated  salt. 

Anhydrous  salt. 

^  =  40 

[«]  ~  =  28.46° 

c  =  38.47        [ 

aft  =  29-59° 

30 

28.08 

28.85 

29.20 

22 

27.76 

21.  l6 

28.87 

20                                     27.51 

19.23 

28.61 

10                           26.94 

9.62 

28.01 

Tliis  formula  follows  for  the  anhydrous  salt : 
[<*]*"  =  27.14  -f  0.0992  c  —  0.000938  c* 

On  the  effect  of  addition  of  KC1  and  NaCl  on  the  rotation  of 
potassium  tartrate,  §70,  p.  245. 

4.  Th.  Thomsen5  found  these  values  referred  to  the  anhy- 
drous salt  : 


p. 

c. 

M* 

Ma 

Ms- 

54-54 

79.24 

30.70° 

30.67° 

30.57° 

36.39            46.55            30.07            30.06 

30.01 

18.09 

20.38 

29.02       29.19 

29.26 

9.07 

9.62 

28.34 

28.49 

28.65 

From  these  observations  we  have  the  following  interpolation 

formulas  : 

[or]  %  =  27.56  +  0.0925  p  —  0.00065  p 
[a]^  =  27.62  +  0.1064^  —  o.  00108  f- 
[flf]aj  =  27.86  -f  0.0951  p  —  o.  00099  /> 

1  Long :  Am.  J.  Sci.,  [3],  38,  267. 

2  Arch.  N£erl.,  VII,  1872. 

3  I^andolt. 

4  Ber.  d.  chem.  Ges.,  ai,  2586. 
^  J.  prakt.  Chem.,   [2],  34,  89. 


550 


CONSTANTS  OF  ROTATION  OK  ACTIVE  BODIES 


Sodium  lartrate,  Na2C4H4O6  +  2H.O. 

1.  Hydrated  c  ==  5  to  15,  /=  22.5°,  \ot]D  =  27.85  -  0.17  cl 

[a]c     [«]/>     [«]/•     [or]*    |» 

2.  Hydrated^^  20,  /=  25°.   20.82  25.79  31.67  32.70  38.49" 

3.  Anhydrous  c=  9. 946,  [or]  £  =  30. 85  (hydrated  =  26.O2).3 

4.  Th.  Thomsen*  investigated  the  following  solutions: 

HYDRATED  SAI/T. 


p- 

c. 

W3- 

\«\™- 

M* 

[<r]f. 

36.77 

45.51 

24.25 

24.28 

24.38 

32.25 

38.90 

— 

24.66 

— 

22.69 

25.87 

... 

25.34 



18.40 

20.46 

25-54 

25-63    i   25.76 

25.90 

13.60  . 

14.69 

.... 

25.82 

— 

9.20 

9.69 

26.01 

26.06       26.28 

26.22 

3.07 

3-n 

26.19 

26.35 

26.31 

.... 

From  this  we  have  for  Na,C4H4O6  -f  2H..O  the  interpolation 
formulas : 

M/f  ~  26-4I  —  0.03615 />  —  0.00061 7  p- 

r«1"  —  26-3°  —  0.02020  ^  —  0.000963  /^ 
[«]^f  —  26.65  ""  °- 03686  p  —  0.000693  p'1 

Potassium  Sodium  Tartrate,  KNaC4H4O8  +  4H,O  (Rochelle 
salt). 

i.  Th.  Thomsen5  has  experimented  with  solutions  made  by 
saturating  sodium  acid  tartrate  with  i  mol.  KOH  and  addition 
of  V,oo  mol.  NaOH  : 


KNaC4H406. 


p. 

c. 

33-68 

25.27 
16.84 
8.41 

42.35 
29.99 
18.86 
8.89 

29.31 
29-46 

29-59 
29.47 

29-33 
29.51 
29.77 
29.52 

29.41 
29-55 
29.80 
29.46 

I 

1  Hesse:  Ann.  Chem.  (Mebig),  176,  122. 
!  Krecke :  Arch.  Neerl.,  VII,  1872. 

*  I^andolt. 

«  J.prakt.  Chem.,  [2]  34.79- 

*  Ibid.,  [2],  34,  90. 


TARTARIC    ACID 


551 


From  this,  calculated  by  Schiitt,    [>]£  =  29.73  —  0.0078  c 
for  c  =-  8  to  43. 
2.  J.  H.  Long.1 


5 

22.14 
29.73 


15 

22.16 
29.76 


25 

22.12 
29.70 


35 

22.13 
29.72 


45 

22.06 
29.62 


[a]* 
27.67 


32.08 


hydrated 
^  anhydrous 

From  this,  calculated  by  Schiitt,  [a]™  =  29.77  —  0.0026  c 
(anhydrous)  for  c  =  5  to  45. 

3.  Krecke2  determined  the  specific  rotation  of  a  solution 
with  c  =  20  for  different  rays  ;  /  =  25°. 

[«]c       [>]/>       WE 
Hydrated       c  —  20       18.52       22.42       26.49 

4.  Anhydrous  c=  10.77,    [«]2^  =  29.67°. 
Lithium  Tartrate,  Li2C4H4O6. 
Anhydrous  c=  8.305,  [or]  3  ='35.84°.' 
Ammonium  Tartrate,  (NH4)tC4H4Ot. 

1.  r  =9.433,  [«]Sf  =  34.26.' 

2.  Krecke4  found  for  different  rays  : 
Anhydrous  ........    [«]?      [«]-5      [^pj 

^=20  ............   31.08        37.09       43.05 

Potassium  Ammonium  Tartrate,   KNH4C4H4O6. 

c=  10.515,     [ci]^  =  -f  31-  "3 

Addition  of  NH4C1  and  of  NaCl  decreases  the  rotation,  while 
that  of  KC1  increases  it,  but  apparently  irregularly  and  notjin 
proportion  to  the  amount  of  salt  added.5 
*  =  2o,      «£=  30.85°. 


45-27       53-76 


In  100  cc.  along  with  20 
grams  of  tartrate. 

C«]s. 

A. 

"\  crams  NH  Cl  . 

70  66 

c  grams  KC1  

10  80 

0.25 
+  O  OA 

10      "           " 

ou-°y 

o1^^ 

2Q  06 

tag 

10      "           " 

^9-9° 

/jQ    rr 

u.oy 

20.51 

2.34 

i  Am.  J.  Sci.,  36,  353- 
-  Arch.  N£erl.,  VII. 
J  I^andolt. 
4  Arch.  N£erl.,  VII. 

Am.  J.  Sci.,  [3],  40,  282. 


552  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Sodium  Ammonium    Tartrate,  NaNH4CtH4O,.  4-  4H,O. 
Rhombic  columns. 

<-  =  9.690  (anhydrous),     [«]^       32.65°  ! 

Magnesium  Jartrate,  MgC4H4O6. 

*  =  8.8i8,     [«]-;;      35.86° ' 

Borohydrotartratc ,       Boryltartrate,         Borotartaric        Acid, 
BO.H.C4H406    See  §70. 

Potassium  Borotartrate,  KBOC4H4O6. 

Obtained  in  aqueous  solution  by  addition  of  i  mol.  of  boric 
acid  to  i  mol.  of  potassium  acid  tartrate. 

1.  c==  2.744,      [«]£  =  5I-48)1 
r=  5.488,      [*]£  =  58.35) 

2.  c  =      5  (dried  at  100°)  '         /  =  20°,      [a]/,  =  58.10' 

f==   20   (       "         "         ";.)  "  •;"-.- 7=5  68.29 

f  ==  10  (dried  over  H8SO4)  -  59.06 

r  =  10  (     "       "         4<      )    /=  29  "   -57-29 

From  the  observations  of  Long  there  follows  according  to 
Schiitt  : 

[a]D=  50.67  -f  1.688  t:  —  0.04036  <*,  for  r  =  5  to  20 

Addition  of  alkali   salts   (especially  potassium  acetate)  in- 
creases the  specific  rotation.3 

Sodium  Borotartrate,  NaBOC4H4O6. 

From  equal  molecules  of  HSBOS  and  NaHC4H4O6  in  aqueous 

solution  : 

c=   2.538,  [«]£>  ^  55.02°  1 ' 
c=-    5.075,  -63.48 

c=  10.151,  =  71.47   j 

Arsenyl  Tartaric  Acid,  AsOC4H5O6. 

Made  in  solution  by  heating  two  molecules  of  tartaric  acid 
with  one  molecule  of  arsenous  oxide. 

c=  12.304,     [a] £  =  16.91°  ' 

1  J.andolt. 

1  Ix>ng  :  Am.  J.  Sci.,  38,  264. 

a  Ix>ng:  Ibid..  [3],  38,  271. 


TARTARIC    ACID  553 

Potassium  Arsenyl  Tartrate,  KAsOC4H4O6. 
Made  by  heating  two  molecules  of  cream  of  tartar  with  one 
molecule  of  arsenous  oxide  to  complete  solution. 
r  =  0.563,     [«]£  =  21.13°  * 

Sodium  Arsenyl  Tartrate,  NaAsOC4H4OH. 
Made  in  solution  from  As2O3  and  NaHC4H4O6. 
*  =  3-358,    O]£  =  20.64°  T 

Potassium  Antimonyl  Tartrate,  Tartar  Emetic,  2(KSbO 
C4H406)  +  H20. 

1.  c  =  5t  t=2$°   [>]<;        [a],,        (XU          M*  [<U 
Hydrated  salt         111.82     138.66     180.39     187.39     21  8.74°.' 

2.  Anhydrous  c  =  5,  t  —  20°,  \ct\D  =    -f  141.  27°.  3 

3.  Anhydrous  r  =  7.982,      [«]£  ==  142.76°,  from  which 
Hydrated  [oc]%  ==  I38.89.1 

On  the  effect  of  addition  of  alkali  salts  on  the  rotation  of  tar- 
tar emetic,  see  experiments  by  Long.4 

Thallium    Tartrate,  2T1,C4H4O6  +  H,O. 
^  =  5  .....  [ar]S  =  4.5820,     [«]~  =  4-758°,     [«]*•«  =  5.704° 

The  specific  rotation  increases  with  rising  temperature  and 
also  by  addition  of  potassium  and  sodium  salts,  especially  by 
potassium  carbonate.5 


Thallium  Potassium  Tartrate,  T1KC4H4O6. 

]D=  10.057° ^ 
=   8.840    I 
"    =    8.173   J 


C=~-     5  =  20 

C  —  10  t  =  20 

C  =  20  /  —  20  "    =  =     8.173 

f  ^=  10  /  =  30  "    ==  10.092  T 


Potassium    and  sodium  salts    increase,  but   thallium   salts 
diminish,  the  rotation. 

1  I^andolt. 

2  Krecke  :  Arch.  N£erl.,  VII. 

3  IX>ng  :  Sill.  Am.  J.  Sci.,  [3],  38,  264. 

«  /Aid.,  [3].  38,  264  ;  40,  275.    See  §70,  p.  245. 

6  lyong  :  Am.  J.  of  Sci.,  [3]  38,  266. 

6  From  this  according  to  Schiitt  :  £  Ot\  ™  =  1  1.672  —  0.3788  c  —  0.01025  c-,  c  —  5  to  20. 

"  Z,ong  :  Loc.  cit. 


554  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Thallium  Sodium   Tartrate,  TlNaC4H4O6  +  4H2O. 
r—    5  (hydrated)      /  =  20     [<*]/?-- 9.07° 

C—  20  "  /=  20  "  =  6.49 

c  =  10  (anhydrous)  /  =  20          "  =  8.60 
r  =  10  "  t  —  28          "  =  9.491 

Sodium  sulphate  increases  and  thallium  sulphate  diminishes 
the  specific  rotation. 

Thallium  Ammonium  Tartrate,  T1NH4C4H4O6. 


\a]%  =  7.S6l 

Increase  of  temperature  and  addition  of  potassium  salts  in- 
crease the  specific  rotation. 

Thallium  Lithium  Tartrate,  TlLiC4H4O6  +  H2O. 
£  =    5  (hydrated)     [a]  £^9.46° 

£=20  "  "       ^6.69' 

Lithium  salts  increase  and  thallium  sulphate  diminishes  the 
specific  rotation. 

Thallium  Antimonyl  Tartrate,  TlSbOC4H4O6  -f  H2O. 

£  =  2  /=20°  [«]/>=  100.44° 

£  =  2  t  =  28  =     99.64  T 

Acetates  produce  a  decrease  in  the  specific  rotation. 
Ethylene  Diamine  Ditartrate,  C2H8Nr2C4H6O6. 


Water  ...........  ^  =  0.36  "       -  1  70.83  2 

On  the  rotation  of  certain  tartrates  in  glycerol  solution,  see 
experiments  by  Long.3 

rf-Tartaric  Acid  Esters 

Monomethyl  Tartrate  (Methyl  Tartaric  Add},  HCH3C4H4O6. 
Sirup. 

Water  ...............   £=2.073     [«r]z>—  18.1° 

Alcohol  .............  ^=1.037         "    —    3,22 

The  salts  of  methyl  tartaric  acid  are  crystalline. 


:  Loc  cit. 
-  Colson  :  Compt.  rend.,  115,  729. 
'*  ).  Am.  Cheir.  Soc.,  33,  813. 


TARTARIC    ACID   ESTERS 


555 


Anhv- 

[#]/> 

f. 

/. 

ar/?.1 

drous. 

.     . 

Water 

2  IA8 

26  «;° 

Alcohol      o  1612 

O   T>4O 

J-/          O<* 

•VJTT      4  t 

4  i 

_    OflT 

28  o 

4  4 

V 

* 

,  • 

*  *  *  * 

K« 

C  C*7 

22  7 

"              o  0088 

S-    j  ^^ 

*OO  / 

**•  / 

Na      "  .. 

(1 

2   151 

21   O 

fi  rim 

n  o/l 

Monoethyl  Tartrate  (Ethyl   Tartaric    Add},   HC,H5C4H4O«. 
Sirup. 


Water.. 
Alcohol 


c  =  2.252     [a}D  =  21.8° 
r  —  1.126         •'    rr=    7.10 


Tartaric  Acid  Salts.     Crystalline.1 


c. 
Anhy- 
drous. 

[«]/>. 

c. 

/. 

or/). 

Li  salt     •  •  .       Water 

2   72Q 

28  8° 

Alrohol 

n  87° 

Nfl     "                            " 

*•$&} 

0.7052 

K      "  " 

•'•OO1 
27  1O 

•'/•J 
21  6 

4  , 

Ca     4>  .                    " 

2  /1CX3 

24  ^ 

Ba     "  

•4-^fVVJ 
3IO7 

2O  "? 

1 

.  AVJ/ 

•"-'•  J 

Dimethyl    Tartrate,     (CH3),C4H4O6.      Crystals.       Melting- 
point  48°;  boiling-point  158.5°  (12  mm.),  280°  (760  mm.)." 

Liquid,  d*  =  1.3403  [«]^  =  1.83°  3 
rf20  =1.3284  [o']^0  =2.14°* 
f/100  =  1.2500  [o:]^0  =6.00 


Diethyl     Tartrate,    (C2H3)2C4H4O6. 
280°  (760  mm.). 


Liquid,    boiling-point 


==    7.47* 


1  Fayollat :  Compt.  rend.,  117,  630. 

'-'  Anschiitz  :  Ber.  d.  chetn.,  Ges.,  18,  1399. 

•'  Anschutz,  Pictet :  Ibid.,  13,  1117,  1538. 

4  Pictet  :  Arch.  sc.  phys.  nat.  [3],  7,  82;  Jahresbericht,  1882,  p.  856. 

5  Anschiitz.  Pictet :  l*oc.  cit. 

e  Pictet  :  Jsb.  Chem..  1882,  p.  856, 


556  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

in-n-propyl  Tartrate,    (C3H.)2C4H4O6.     Liquid,    boiling-point 
303°  (760  mm.). 

</«7  =1.1392    [a]  J?  *=  12.09°  ' 

rf20  =  1.1344    [arj™  =  i2-44 

d™  =  1.0590     [flfjE0  =  17-11  2 

Diisoptopyl  Tartrate,  (CH3.CH3.CH)2C4H4O6.     Liquid,  boil- 
ing-point 275°  (760  mm.). 

</*>  ^^.1300      [«]£   =  14.89° 
d™  =  1.0537      [a]£°  =  18.82  * 

Diisobutyl  Tartrate,  [(CH3)2CH.CHJ2C4H4O6.     Solid,  melt- 
ing-point 68°,  boiling-point  323°  to  325°  (760  mm.). 
arioo  —.  I-OI45    [a]^°  =  19.87°  2 

Potassium  Ethyl  Tartrate,  KC2H5C4H4O6- 


Barium  Ethyl  Tartrate,  Ba(C2H5.C4H4O6)2. 

Water  .....  £=12.586     [«]»  —  25.68°  3 

d-Diacetyl  Tartaric  Acid  Compounds 

d-Diacetyl     Tartaric  Acid, 

COOH.CH(OC2H3O).CH(OC2H3O).COOH. 

(Also  with  3H2O.  )     Left  rotating  in  water,  methyl  alcohol  and 
ethyl  alcohol  (Pictet),  also  in  ether  and  benzene.4 

Water          c=       17-947     U-357     11.486      9.189      7.351       4.705      3-7&4 

"     [**]£  =  —23.04  —  22.48—22.16—21.50—21.33—20.07  —  19.32° 

Alcohol  ....................  c=         7.367  4.911  3.274 

11     ....................    [«]"=    ~23-63         -23.14         -21.52° 

Methyl  alcohol  (d  =  0.824)  ..  ^=4.681      [«]^  =-  23.74°  5 

The  sodium  and  barium  salts  are  also  left  rotating.6 

d-Diacetyl  Tartaric  Acid  Anhydride,   (C2H3O.O)CH.CO)aO. 
Right  rotating.   Prismatic  crystals.   Melting-point  125°  to  129°. 

Anschiitz,  Pictet  :  Loc.  cit. 

Pictet  :  Loc.  cit. 

I^andolt. 

Colson  :  Compt.  rend.,  114,  175. 

Pictet  :  Jsb.  Chem.,  1882.  p.  856,  857. 

Anschiitz,  Pictet  :  Ber  d.  chem.  Ges.,  13,  1178. 


TARTARIC    ACID    ESTERS  557 

In  benzene.  In  acetone. 


f  2.091  1.045  11.656  4.403 

[a]/,  58.69  63.05°  59-7o  62.04°  ! 

The  esters  of  diacetyl  tartaric  acid  may  be  distilled  at  the 
ordinary  temperature  without  suffering  a  change  in  their  rota- 
ting power." 

Dimethyl  Ester,  (CH3)2(C2H3O),C4HA-  Rhomboidal  prisms. 
Melting-point  103°.  According  to  Pictet*  left  rotating. 

Alcohol  (d  =  0.826) £  =  3.566     [a~\$=   -  14-23°  ' 

^  =  3-254     [<*]£  =    -14-29 

Diethyl  Ester,    (C2H5)2(C2H3O)2C4H,O(i-      Triclinic    prisms. 

Melting-point  66.5°,  boiling-point  291°  to  292°.      [of]y)  for  the 

superfused  ester  =  :  -f  5.o°.4 

Alcohol  (d  =  0.826) c  =  23.644    [«]$  =  +  1-02°  ' 

On  the  rotation  in  chloroform  solution  see  §57. 

N-Dipropyl  Ester,  (C3H.)2(C2H3O),.C4H,O6.  Crystals,  melt- 
ing-point 31°,  boiling-point  313°. 

Alcohol  (d  =  0.826) c=  7-855     [a]#  =  +  7-04°   * 

c  =  3-253     [or]]!?  =  -  6.52 

According  to  Freundler,5  the  ester  is  liquid  at  the  ordinary 
temperature,  [or]/,  =  13.5°.  Its  specific  rotation  changes 
greatly  with  solution  in  different  liquids.  See  §59. 

N-Dibutyl Ester,  (C4H9)2(C2H3O)2C4H2O6.  Liquid.  f  =  2o°, 
lai]D=:  +  17.8°. 4 

Diisobutyl  Ester,  (C4H9)2(C2H3O)2.C4H2Ofi.   Liquid.    Boiling- 
point  322  to  326°.     /  =  about  20°,  [<*]D  =    +  11.3°.  4 
Alcohol  (d  =  0.826) ....  c  -=  13-559     [0]%  =  +  10.51°  ! 

••••   c=    7-953     |>]'J  =  ~   IO-29 
Compounds  of  diacetyl  tartaric  acid  with  ethylene  diamiue. 

Neutral  Salt,  C2HSN2.2C8H10O8.     Crystals. 

Water ^=11.5     \CC\D—   --12.74° 

1  Pictet. 

2  Freundler;  Compt.  rend.,  115,  509. 

3  Loc.  cit. 

4  Freundler. 

5  Compt.  rend..  117,  556. 


on  : 

[a]  %  =  -  110.91 

[«]/?=  -112.05 

[#]  £  =  -  1  16.30 


558  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Add  Salt,  C,H6N.,.C8H10O8.     Crystals. 

Water  ..........   r^u.5     [«]/>  =   -17.05°* 

Numerous  further  determinations  of  rotation  of  esters  of 
dipropionyl,  dibutyryl,  di-w-valeryl  and  di-rc-caproyl  tartaric 
acid  have  been  made  by  Freundler.2 

For  the  rotation  of  the  esters  of  di-monochloracetyl  tartaric 
acid,  see  Franklin  and  Turnbull.3 

See  McCrae  and  Patterson'  for  other  derivatives  of  diacetyl 
tartaric  acid. 

Compounds  ofd-Dibenzoyl  Tartaric  Acid. 
Dibenzoyl    Tartaric  Acid,     COOH.CH.O(CTH5O)  — 
CH.O(CTH5O).COOH  -f  HaO.     Crystals.     Melting-point  90°. 

With  Water  of  Crystallization  : 
Alcohol  (d      0.818)  .........  <r«=  8.933 

"'      .........  c  =  4-994 

Methyl  alcohol  .............   c=  4.857 

Anhydrous  : 

Alcohol  (d  =  0.818)  .........  £  ^  8.506  f  at]  %  1  16.47°  :> 

.........  c  -  -4-755  [or]  J?  -117.68 

Methyl  alcohol  .............  £--4.625  [«]$--  -122.14 

Dibenzoyl  Tartaric  Acid  Anhydride,  (C7H5O.O.CH.CO)2O. 
Crystals.     Melting-point  174°. 

Acetone  ..........  c  =  4.644     [#]  Jf  =  H-  142.94° 

..........  c—  1.572     [«]  *      -f  143-22  G 

[«]/»  IJ47 

Dibenzoyl   Tartaric  Acid  Dimethyl  Ester,   (CH3)2(C7H5O)2- 
C4H,Ofi.     Crystals.     Melting-point  132°. 

Alcohol  ..........  c—    0.245      \_df\  7,'        —  96.61  ° 

Chloroform  ......  c       11.612     [a]J_?        —88.24 

......  C*=   8.598     [a]^=   -  88.78  6 

Dibenzoyl  Tartaric  Acid  Diethyl  Ester,  (C0H5).XC.H5O)2 
C4H206.  Liquid. 

1  Colson  :  Compt.  rend.,  115,  729. 

-'  Compt.  rend.,  115,  509,  556;  Bull.  soc.  chim.,  [3],  9,  680;  n,  366,  470;  13,  1055. 
Ann.  Chim.  Phys..  [7],  3,  433  ;  4,  244. 

*  ].  Chem.  Soc.,  73,  203  (1899).      . 
4  Ibid.,  77,  1096  (1900). 

I'ictet  :  Jsh.  Chem.,  1882,  p.  857. 

•  Pictet. 

'  Freundler  :  Hull.  soc.  chim..  [3]  7,  804. 


TARTARIC   ACID    ESTERS 


559 


Alcohol  (d       0.815) 


C  9-J75 
£  =  5-733 
c  =  2.693 


Dibenzoyl  Tar taric  Acid  Diisobutyl  Ester,  (CJIJ.XCH.O).,. 
C4H.,OK.  Liquid. 

Alcohol  (d  r.=  0.818)  c  =  14.085  [#]£  =    -  48.86° 

*==   4.922  [or];?-   -42.94 

<:==    2.880  [a]  jj  =   -41-95  ! 

Diphenyl  Acetyl  Tartaric  Acid  Anhydride,  (C7H..CO.,.CH. 
C0)20.  [«]„==  +  58°.-' 

Diphenyl Propionyl  Tartaric  Add  Anhydride,  (C,Hf(.CO9.CH. 
C0)20.  '  [«]*  =  +  38V 

Frankland  and  Wharton4  and  Frankland  and  McCrae5  have 
given  the  following  determinations  : 


Kb. 

Dicthvl  Tnonofocnzovl  tHFtratc                     •        • 

-7/1° 

24 

20.71° 

38 

4-  20.18 

63 

4-    19.02 

79 

4-  18.43 

99-5 

-f   17.69 

135.0 

+   16.36 

- 

IOO 

137 

-  66.84 

183 

-  58.94 

Diethyl  dibenzoyl  tartratc  

TQ 

—  _       ,*£• 

10 

—     59-36 

38 

-     61.70 

44 

-     62.05 

53-5 

-     62.28 

60 

-     62.28 

IOO 

-     60.77 

^T/*      f^Q 

I4 

12.  OO 

. 

20 

+    11.82 

32.5 

11.74 

65 

11.20 

IOO 

-f-    10.88 

136.5 

4-    10.62 

'  Pictet. 

-  Freundler  :  Bull.  soc.  chim.,  [3],  7,  804. 
3  Freundler. 

*  J.  Chem.  Soc.,  69,  1309,  1583  (1896). 
5  Ibid.,  73,  307  (1898). 


560 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


t. 

M  . 

1 

14.5 

20 
54 

100 

136 

100 

109 

138 

180 

12 
19 
33-5 
54-5 
70 
100 

136 

100 

136 

183 

100 

135.5 
183 

II 

30 

49 
70 

100 

135 
20.5 

24.5 

44-5 
50 

100 

136 

100 

137 
183.5 

+  13-63 
-f  13-59 
+  13.28 
+  12.57 

-f  11.92 

+  15.85 

4-  15-44 
+  H-59 
+  I3-38 

-   77  82 

//.CM 

78.42 

-  77.00 

-  74-23 
-  72.02 
-  68.10 
-  61.28 
-  79.02 
-  70.58 
>  60.96 

IO2  82 

76.90 
60.37 
-  60.33 

-  59-53 
-  57-96 
-  54-73 
-  50.37 

°9-3I 
-  68.87 
69.16 
69.00 
-  63.74 
-  58.71 
-  89.98 
-  81.46 
-  69.50 

The  observations  were  made  in  tubes  44  to  50 mm.  in  length, 
and  specific  gravity  determinations  were  made  over  a  suffi- 
ciently wide  range  of  temperature  to  allow  the  calculation  of 
the  specific  rotation. 


TARTAKIC    ACID    ESTERS  561 

I  m  ides  of  d-  Tartaric  Add  and  Benzoyl  Tartaric  Acid 
The  following  data  are  from  Ladenburg.1 

Methyl  Tartrimide.     Made  by  heating  methylamine  bitar- 
trate,  by  which  partial  racemization   followed.     Melting-point 
178°. 
CO 


Water,  /  7.31       </==  1.0242 


"       /          12.94      rf-  1.0445  "        +192.6 

From  which  [a]  />=  196.30  —  0.2877  p  for  /  —  7  to  13. 


By  heating  methyl  tartrimide  with  2  mols.  of  benzoyl  chlo- 
ride there  result  : 

a-Dibenzoyl  Methyl  Tartrimide.     Melting-point  56°. 
Ethyl  acetate  ................  p  =    7.93     [a]/>=  +  183.9° 

"     ................  />-  15-83  -  +  185.7 

ft-Dibenzoyl  Methyl  Tartrimide.   Melting-point  106°  to  108°. 
Ethyl  acetate  ................  p         7.93     \a\D  =  +  188.8° 

"          ................      />•:--    15.84  "==+189.8 

Ethyl   Tartrimide,   C4H4O4.NC.,H5.      Melting-point  171°   to 

174°. 

Water  .......................  p  5.76  [«]/>=  +  164.9° 

"       .......................  p  -7-32          "    =-+165.6 

>(       .......................  />  8.57                  =.f  166.2 

Changes  in  the  Specific  Rotation  of  d-  Tartaric  Acid  in 
Presence  of  Inactive  Substances 

If  different  bodies  are  added  to  aqueous  solutions  of  tartaric 
acid,  the  degree  of  its  electrolytic  dissociation,  as  explained  in 
§  61,  is  altered,  and  as  the  latter  is  reduced,  the  specific  rota- 
tion is  lowered.  This  follows  on  addition  of  acids,  alkalies, 
alcohols  and  other  bodies  and  the  decrease  in  the  right  rotation, 
so  caused,  may  extend  in  certain  cases  to  inactivity,  or  even  to  a 
change  to  left  rotation.  When  an  increase  in  activity  is  ob- 
served, as  by  addition  of  boric  acid,  molybdic  acid,  or  alkalies, 
this  depends  on  the  formation  of  complex  compounds  of  tar- 
taric acid,  as  referred  to  also  in  §61. 

1  Bcr.  d.  chem.  Ges.,  29,  2710. 
36 


562  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Of  the  many  observations  bearing  on  this,  a  number  have 
been  referred  to  in  the  general  part  of  the  work  (see  §§59,  61, 
70)  ;  in  regard  to  others,  it  is  sufficient  here  to  refer  to  the 
original  papers.  Most  of  these  have  a  limited  value  only,  be- 
cause they  are  based  on  determinations  with  but  few  concen- 
trations, and  the  corresponding  data  concerning  the  degree  of 
dissociation  are  lacking. 

Inorganic  and  Organic  Acids  (see§6i).  These  produce  a 
decrease  in  the  right  rotation.1  Amido-acetic  acid  and  amido- 
propionic  acid  increase  the  activity. 

Alkalies  bring  about  a  decrease  in  the  right  rotation  of  alkali 
tartrates,  which  may  extend  to  left  rotation.- 

Alkali  Salts  produce  sometimes  an  increase,  sometimes  a  de- 
crease in  the  rotation  of  the  tartrates.  §70.' 

Molybdates  and  Tung  states.  Increase  in  rotation  to  a  maxi- 
mum point.  §70. 

Alcohols.     Decrease  in  rotation . 4 

Acetone.     Decrease.5 

Benzene  and  Homologues,  mixed  with  alcohol,  produce  left 
rotation.  §59." 

Organic  Haloid  and  Nitro  Compounds.  Decrease  in  the  right 
rotation  or  change  to  left  rotation.  §5Q.7 

Inactive  Organic  Bases  (aniline,  pyridine).  The  right  rota- 
tion increases  to  a  maximum  and  then  decreases.8 

Amido  compounds  (urea,  glycocoll,  alanin)  produce  increase 
in  the  rotation.  Urea,9  glycocoll,  alanin.10 

/-TARTARIC  ACID.  i.  Water  p  =  35.7,  t  =  17°  ;  Biot'sred 
ray[«]r=  -8.43°. 

1  Biot  :  Mem.  del'Acad.,  16,  229.  l,andolt  :  Ber.  d.  chem.  Ges.,  13,2331.  Th.  Thom- 
«cn  :  J.  prakt.  Chem.,  [2],  32,  219;  Pribram  :  Sitzber.  Wien.  Akad.,  97,  II,  13. 

s  Th.  Thorosen  :  J.  prakt.  Chem.,  [2].  35,  145.    Aignan  :  Compt.  rend.,  112,  1009. 

«  F.  Schutt :  Ber.  d.  chem.  Ges..  ai.  2586  (KC1  and  NaCl).  Long  :  Sill.  Am.  J.  Sci., 
[3].  36,  351  ;  38,  264  ;  40,  275.  Th.  Thomsen  :  J.  prakt.  Chem.,  [2],  34,  83. 

4  Biot :  Mem.  de  1'Acad.,  15,  240.  I«andolt  :  Ber.  d.  chem.  Ges.,  13,  2332.  Pribram: 
Sitzber.  Wien.  Akad.  97,  II,  468. 

•  Landolt :  Ber.  d.  chem.  Ges.,  13,  2332.    Pribram  :  Sitzber.  Wien.  Akad.,  97,  II,  463. 

•  Pribram  :  Ber.  d.  chem.  Ges.,  aa,  6. 
'  Pribram:  Ibid.,  aa,  7. 

•  Pribram  :  Ibid.,  aa,  9. 
'  Pribram  :  Ibid.,  aa,  8. 

10  Pribrnni  :  Sitzber.  Wien.  Akad.,  97,  II,  479. 


TARTARIC   ACID   ESTERS 


563 


For  right  tartaric  acid  under  the  same  conditions,    [a~\r  = 

+  8-58 

2.  The  review  of  Pasteur's1  observations  by  a  committee  con- 
sisting of  Biot,  Dumas,  Regnault,  and  Balard  furnished  the 
following  values  :' 


A 

rff.      /. 

< 

ar.            [<*]  r. 

Levotartaric  acid  .  . 
Dextrotartaric  acid 

42.06 
41-97 

1.21785     5.198 
1.21765     5.198 

20.5° 
20.5 

-21.485° 
+  21.452  > 

i 

—  8.070° 
+  8.082 

Addition  of  boric  acid  increases  the  left  rotation  in  the  same 
degree  that  it  increases  the  right  rotation  of  dextrotartaric 
acid.  The  committee  named  cite  the  following  parallel  experi- 


ments : 


3 


Tartaric 
acid. 

Boric 
aci, 

Water.            rf 

/. 

/. 

ar. 

Wr* 

Levotar- 

taric acid 

23.89 

4.76 

71.35       1.13181 

5.198 

23.2 

—  52.12° 

-  37.08° 

Dextro- 

tartaric 

acid...,    23.78 

4.80  ;     71.42        1.13158 

5-1935 

23-2 

-f  53-07 

+  37-97 

Salts  of  I-  Tartaric  Acid 
l-Ammonium  Tartrate,  (NH4)2C4H4O6. 
Water  p=  12.16,   /=  18.2,    [a]j  =  —  38.20*  from  which 

by  multiplication  with  --we  have   [oi]r  = — 29.29.     For  the 

^/-salt  Biot  found  [<*]r  =  -f  29.0. 

/-Sodium  Ammonium  Tartrate,  NaNH4C4H4O6  -f  4H2O. 

Water/ =33.33,  /=  16.5,  [flf]y  =  — 26.0°  * 

The  solubility  is  the  same  as  with  the  d- salt. 

Levotartar  Emetic,  KSbOC4H4O6  +  ^H2O. 

Water p=  6.80,  /  =  19°,  [«]y  = — 156.2°.     Asimilarsolu- 
tion  of  the  af-salt  gave  [a]y=  +  156. 2°. 6 

Ann.  chim.  phys.,  [3]  28,  77. 
Ibid.,  [3],  28,  101  to  105. 
Ibid.,  [3],  28,  no  to  112 
Pasteur:  /bid.,   [$,  28,  84. 
Pasteur  :  Ibid.,  [3],  28,  90. 
Pasteur  :    Ibid.,  [3],  28,  87. 


564  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

/-Calcium  Tartrate,  CaC.H.O,  +  4H2O,  dissolved  in  hydro- 
chloric acid  shows  right  rotation.  A  solution  of  20  grams  of 
the  salt  in  63  cc.  of  hydrochloric  acid  (containing  7.09  grams 
HC1)  showed,  for  /=  3.9  dm.,  or,  =  =  -f-  6.7°.  If  ^/-calcium 
tartrate  is  dissolved  in  hydrochloric  acid  the  solution  shows 
left  rotation.1 

Combinations  of  d-  and  I-  Tartrafes  with  d-  and  l-Malates 

Right  ammonium  acid  tartrate  and  left  ammonium  malate 
form  a  crystallizable  combination  which,  when  dissolved  in 
aqueous  ammonia,  shows  the  same  rotation  as  a  mixture  of 
equal  molecules  of  the  two  salts. 

<•       4,     [<b        T-  I4.50" 

^-Ammonium  acid  tartrate  and  /-ammonium  acid  malate 
form  no  combination  with  each  other. 

Combinations  of  d-  and  /-tartramide  with  /-malamide. 

d-Tartramide,  [>},.  =  +  i33-9°- 

I- Tartramide,  \oi\j  -     -  134. 15°,  for  c  =  =  1.305. 

l-Malamide,       [«]_,-  =          47-5°. 

d-  Tartramide  and  I- Mai  amide  >  dissolved  in  equal  molecular 
proportions,  yield  an  easily  crystallizable  compound  : 

d-  Tartro-l- malamide,  \a\  j  —  -f-  43 . 02  ° . 

I- Tartramide  and  I- Malamide,  dissolved  in  equal  molecular 
proportions,  yield  also  a  crystallizable  compound  which  is  more 
soluble  than  the  last : 

/-  Ta rtro-l-  mala m ide ,  [a]j  =     -  9 5 . 7 1  ° . :t 

</-Tartaric  acid  forms  with  asparagin  an  easily  crystallizable 
compound,  but  /-tartaric  acid  does  not.4 

/-QuiNic  ACID,  C7H12O6. 

1.  Water,         c-  2  6  10 

I>]B=     -44-09      -43-84      -43-755 

2.  Water,  c  ==  8.9  to  53.03,  [>]',•  =     -  43.8  to  43.9." 

3.  Water,  c  =  =  1.57  to  12.71,  [ar]*  =      -  45.5  to  45.7. 7 

Pasteur  :  Ann.  chim.  phys.,  [3],  a8,  78. 
Pasteur:  Ibid.,  [3],  38,  464. 
Pasteur  :  Lac.  «/.,  p.  465. 
Pasteur :  Loc.  cii.,  p.  437. 
Hesse:  Ann.  Chem.  (I.iehig),  176,  124. 
Eykman  :  Ber.  d.  chetn.  Ges.,  34,  1297. 
Oudemans:  Rec.  trav.  chim.  Pays.-Bas.,  4,  166. 


ACIDS  WITH  SEVEN  ATOMS  OF  OXYGEN  565 

4.   Water,/       9.931029.50,  \_a]™=    -43-47      -  0.0230^. ' 

Quinates.  The  rotation  decreases  somewhat  with  increasing 
dilution,  and  finally  reaches  nearly  the  same  value  for  all.2 
See  $6 1.  Addition  of  free  alkali  produces  an  increase  in  the 
specific  rotation  in  consequence  of  a  decrease  in  the  extent  of 
dissociation/1 

12.  Acids  with  Seven  Atoms  of  Oxygen 
See  the  aldehydes  under  group  16  (oxyaldehydes,  sugars). 

</-GLUCONIC  ACID  (Dextronic  acid,  Maltonic  acid),  CH..OH. 
(CH.OH)4COOH  ==  C6H1S07- 

The  free  acid  is  a  sirup,  which  by  long  standing  over  sul- 
phuric acid  is  partly  converted  into  the  lactone,  C6H10O6 ;  a 
complete  conversion  follows  by  prolonged  heating  to  iooV 
On  the  reciprocal  transformation  of  the  acid  and  lactone  in 
aqueous  solution  at  the  ordinary  temperature  see  Multi rotation, 
§75- 

Calcium  Salt,  Ca(C6HuOT),  +  H,O  (from  dilute  alcohol). 

Water c  —  1.8176,  after  10  minutes  [«]/>     =  -f-  7.92° 

Water c  -  i  hour  —  5.94°  to  4.8° 

Exhibits  multirotation. ' 
Ca(C6HnO7)2  +  2H..O  (from  water). 

Water c   -  10  (anhydrous),      [<*]}?  6.66°  K 

•'       c       10          "  "  7°  ' 

Shows  no  multirotation/ 

Anhydride,  C6H10O6.     Crystals.    Melting-point  130°  to  135°. 
Water p       8.32,  dv>  =  1.032,  /  —  20°,  [<*]/>  =  +  68.2° 

At  the  end  of  twenty-four  hours  the  rotation  had  fallen  to 
64.2°,  but  the  solution  had  an  acid  reaction,  evidently  because 
free  acid  had  been  formed." 

i  Thomstn  :  J.  prakt.  Chem.,  [2],  35,  156. 

-  Oudemans  :  Loc.  cit. 
•'•  Thonisen  :  IMC.  cit. 

4  Fischer  :  Ber.  d.  chem.  Ges.,  23,  2625. 

•"•  Herzfeld  :  Ann.  Chem.  (L,iebig),  220,  345. 

1-i-cher  :  Ber.  d.  chem.  Ges.,  23,  2614. 
7  Schnelle,  Tollens. 

-  Fischer. 

-  her  :  Ber.  d.  chem.  Ges..  23,  2626. 


566  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

/-GLUCONIC  ACID.  The  mixture  of  acid  and  lactone  rotates- 
strongly  to  the  left.1 

Calcium  Salt,   Ca(C6HHO7),  (dried  over  H2SO4).     Needles. 

Water p=  10.298,  rfj°=  1.049,  t=2o°,  [«]/?=  -  6.64°  - 

Anhydride.  The  rotation  was  determined  in  a  hydrochloric 
acid  solution  of  calcium  gluconate. 

c  =  6.9  (anhydride),     t  =  20°,       [«]/>,  =   —  22.0°  T 

</-MANNONIC  ACID,  C6H12O7. 

Anhydride,  C6H]0O6.     From  </-mannone  by  oxidation  with 
bromine.     Glittering  needles.     Melting-point  149°  to  153°. 
Water ^  =  9.99,     </^°  =  1.0381,     /  =  20°,     [>]/>--= -f-  53.81°  :; 

/-MANNONIC  ACID  (Arabinose  carboxylic  acid). 
Anhydride,  C6H10O6.     From  arabinose  and  hydrocyanic  acid. 
Rhombic  crystals  which  soften  between  145°  and  150°. 

Water p  —  9.1807,     rf=  1.0329,     [«]/>=  —  54.8°  * 

</-Guix>Nic  ACID,  C6H12O7. 

Anhydride,  C6H10Q6.  From  ^-saccharic  acid  by  reduction. 
Trimetric  crystals.  Melting-point  178°  to  180°. 

Water. . . .  p  =  10.219,     d  —  1.0373,     t  =  20°,     [a]/,  ==  -f  55.1°  5 
From  glucoronic  acid  : 

Water c=  2.157,     t  =  19°,     [«]„--=+ 56.1°  «   • 

Calcium  salt [a]z>  =    —14.45° 

/-GuLONic  ACID  (Xylose  carboxylic  acid). 
Anhydride,   C6H10O6.     From  xylose  and  hydrocyanic  acid. 
Trimetric  prisms.     Melting-point  185°  (cor.). 

Water. . . .  p  =  9.15,  d  —  1.034,  /  =  20°,  [a]/,  =    -  55.3°  ' 

^-GALACTONIC  ACID,  C6H12O7. 

On  the  multirotation  of  the  free  acid,  separated  from  the  cal- 
cium salt  by  aid  of  hydrochloric  acid,  through  change  into 
the  lactone,  see  §75. 

Fischer. 

Fischer  :  Her.  d.  chem.  Ges.,  33,  2614. 

Fischer,  Hirschberger  •  Her.  d.  chem.  Ges.,  22,  3218. 

Kiliani  :  Ibid.,  19,  3034. 

Fischer,  Piloty  :  Ibid.,  34,  521. 

Thierfelder  :  Ztschr.  physiol.  Chem.,  15,  71. 

Fischer,  Piloty. 


ACIDS  WITH  SEVEN  ATOMS  OF  OXYGEN  567 

Calcium  Salt,  Ca(CtiHnO7),  -f  5H..O.      Monoclinic  crystals. 
Water  -j-  HC1,  c  =  0.76°,     /  =  15°,     [a]  />  =  about  +  2.85° 

But  if  the  calcium  salt  is  decomposed  by  oxalic  acid,  two 
crystalline  substances  result  :  i,  C6H12O7  (=C6H10O6+  H2O), 
with  melting-point  65°,  and  2,  C6H10O6,  with  melting-point  90° 
to  92°.  The  first  is  not  the  true  galactonic  acid,  but  the  hy- 
drate of  the  anhydride.1 

TALONIC  ACID,  CtiH12O7.  Made  by  heating  ^/-galactonic 
acid,  pyridine  and  water  to  150°.  The  mixture  of  acid  and 
anhydride  is  strongly  left  rotating.2 

</-!DONIC  ACID,  C8H12O7- 

Double  Salt,  (C6HnO7)2Cd  -f-  CdBr2. 

p  =  n.  14,     d—  1.078,    t  =  2Q°,     [a\D  =  -r  3-41°  3 

/-IDONIC  ACID. 

Double  Salt,  (C6HHO7)2Cd  +  CdBr.,. 

^    —    10.562,        </   1.076,         /  =   20°,         [<*]/>     =       —   3.250    * 

RHAMNOHEXONIC  ACID  (Isodulcite  carboxylic  acid),  CH3. 
(CH.OH),.COOH  =zC7H14O7- 

Anhydride,  C7H12OB.     Crystals.     Melting-point  168°. 

Water ^=10.034,     t  =  20°,     [a~\D  - -  —  83.8° 

Shows  no  multirotation.5 

/-TRIOXYGLUTARIC  ACID,  C.HSO7. 

By  oxidation  of  arabinose  with  nitric  acid.  Microscopic 
plates.  Melting-point  127°. 

Water p  ^=9.59,    rf  =  1.0441,  t  =  20°,   [a-]/>  =    —22.7° 

The  rotation  remained  unchanged  after  twenty-four  hours.6 

Potassium  Salt,  K2C5HBO7.     Monoclinic  plates  or  prisms. 

i .   From  rhamnose  : 
Water p       10.863.     rt^0  =  1.0685,     '  =  16°,    [a}D  —  -f  9.35° 

"  />  9.192,  "       r=    1.0569,        /=I3°,  "       =  9-50 

/»-=29.49S,  "        =1.1935,        ^-=14°, 

1  Schnelle  and  Tollens  :  Ann.  Chem.  (I^iebig),  271,  82. 

-  Fischer  :  Her.  d.  chem.  Ges.,  24,  3623. 

'•'  Fischer,  Fay  :  Ibid.,  28,  1982. 

4  Fischer.  Fay  :  Ibid.,  28,  1977. 

'  Fischer,  Piloty  :  Ibid.,  23,  3104. 

«i  Fischer:  Ibid.,  24,  1836.  2686. 


568 


CONSTANTS  OF  ROTATION  OF  ACTIYK  BODIES 


2.   From  arabinose. 
Water />         3-"74i.</?'        1.0186,  /       19°,  [<v]/>  ••-} -9.13°  ' 

GLUCURONIC  ACID,  COOH(CH.OH)4.CHO  =  C,H10O7- 
Potassium  Salt,  KC8H!(O.  (at  100°),  needles. 

Water p       3.85.       /        18°,     [a]/,         ,21.25° 

••      />       1.925.     /  —  18°,          "  21.82 

The  specific  rotation  increases  on  dilution.  The  potassium 
salt  rotates  as  strongly  as  does  the  amount  of  anhydride  con- 
tained in  it. 

Anhydride.  From  euxanthinic  acid.  Monoclinic  crystals. 
Melting-point  175°  to  178°  (with  decomposition). 

Water f>        14.14       ,/  '8        1.06201,      [«]#-••-  19.15° 

9-575,  -  1.04125,  19.26 

7.719,     "          1.03307,  19.35 

7.07,  "  =       20.06 

4.787,  19-22 

'       "=-    3-86,  19.89 

-    3-54,  20.93 

2.39,  21.80 

11      "          1.93,  21.66 

Effect  of  temperature  r 

p.  [<|z?at 
5°                     18°  28°  34° 

Water j       14.14         +17.61°     -f  19.15°  j    >    20.83°      +21.00° 

9-575  17-63  19-26  20.37  21.10 

7.719  17.72  19-35  20.47  21.27 

Water c       3,     /       21°,     [cr]/,.  =  19.4°  :t 

OXYGLUCONIC  ACID,  C6H10O7  +  2H2O.     Sirup. 

Water p       2,     [>]„         -14.5°  ' 

SACCHARONIC  ACID,  COOH.C.OH.CH3(CH.OH  X.COOH- 
C.H1007. 

Anhydride  (Saccharon),  CBHKO6  +  H2O.  Formed  by  the 
oxidation  of  saccharin  with  nitric  acid.  Triclinic  plates. 
Melting-point  156°. 

Water  ....  />  =  12.41,     d       1.0451.     /        18°,     [a]/,  6.1°' 

Will,  Peters:  Ber.  d.  chem.  (ies.,  22.  1697. 

Thierfelder  :  X.tschr.  physiol.  Chem     i , 

Kiilz  :  Ztschr.  f.  niol.,  aa,  478. 

Boutroux  :  Ann.  chim.  phys.,  [6],  ai. 

Kiliani:  Bcr.  d.  chem.  O**.,  15,  2959. 


ACIDS  WITH  EIGHT  ATOMS  OF  OXYGEN  569 

13.  Acids  with  Eight  Atoms  of  Oxygen 

LKVULOSECARBOXVLIC  ACID, 

CH,(OH).C(OH.eOOH)(CH.OH),CH,OH  ==  C:HMO,- 
AnJiydride,    plates  or   prisms,    C-H12O7.      Softens    at    126°  ; 
melting-point  130°. 

Rotates  strongly  to  the  right  in  6  per  cent,  aqueous  solution.1 

^-GLUCOHEPTOXIC  ACID  (Dextrose  carboxylic  acid ),CH.,OH. 
<  CH.OH)..COOH  =  C7HH(X. 

Anhydride,  C7HI2O7.      Rhombic  crystals. 

Water...  p  =   3-3<Sl7,  rf  =  1.0144,  /        17.5°,   [«]/>  =        55-3° '' 
/?-GLUCOHEPTONIC  ACID. 

Anhydride^  C.H^O..  Colorless  needles.  Melting-point  151° 
to  152°  (uncor. ). 

Water  .../>- 10.049.     d     ^1.0372     /   -  20°     Multirotation. 

After  20  minutes [a]/7  —    —79.1° 

After  24  hours  constant —  67.7 

The  multirotation  is  not  caused  here,  as  with  the  other  lac- 
tones,  by  transformation  into  the  acid,  since  at  the  end  of  the 
experiment  the  solution  is  found  perfectly  neutral. :; 

^-GALACTOSECARBOXYLIC  ACID,  CH,OH.rCHOH)5CO2H. 
vSmall  needles  ;  melting-point  145°. 

The  rotation  of  aqueous  galactose  solutions,  to  which  hydro- 
cyanic acid  has  been  added  in  excess  at  the  ordinary  temper- 
ature, decreases  gradually,  and  finally  becomes  o.  The  amide 
of  galactose  carboxylic  acid  is  formed,  which  on  boiling  with 
water  is  decomposed. 

The  acid  is  inactive  in  5  per  cent,  aqueous  solution  (/  = 
2  dm.).* 

Barium  Salt,  Ba<  CH^OJ,.  From  the  amide  on  boiling 
with  baryta  water. 

Water c       12.01,     /  =  20°,     [a~\D  ---  5.50° 

*/-MANNOHEPTON'ic  ACID  (Mannose  carboxylic  acid), 
CHaOH.(CH.OH;5.COOH.  Melting-point  175°.  Rotates 
slightly  to  the  left  in  aqueous  solution. 

1   Kiliani  :  Ber.  d.  chem   (",es.,  19,  1915. 
-  Kiliani  :  Ibid.,  19,  770. 

Fischer  :  Ann.  Chem.  (Liebig),  270,  84. 
4  Maquenne  :  Conipt.  rend..  106, 


570  CONSTANTS  OF  ROTATION  OF  ACTIVE   BODIES 

Anhydride,  C7H12O7-     Crystals.     Melting-point  148°  to  150°. 

Water c  =  10.009,     t       20°,     [<*]/>       74.23° 

Slight  decrease  later.' 

/-MANNOHEPTONIC  ACID. 

Anhydride,  C.H12O_.     Crystals.      Melting-point  153°  to  155°. 
From  /-mannose  by  the  cyanhydric  reaction   and  saponifi- 
cation. 

Water    ..  p  =.-.  5.27,     d™  =  1.02,     /  =  20°,     [a]/,  *=  +  75.15°  - 

RHAMNOHEPTONIC  ACID,  CH3(CHOH),..COOH.  From 
rhamnohexose  by  hydrocyanic  acid. 

Anhydride,  C8H14O7.     Crystals.     Melting-point  160°. 

Water c=  10.036,     /  =  20°,     [or]/,  =  -f  55.6° 

After  six  hours  the  rotation  was  still  unchanged. 

Saccharic  Adds,  CO2H.(CHOH)4.CO2H  =  C.H10O8. 

</-SACCHARIC  ACID. 

Anhydride,  Lactone,  CgH8O7.  Needles.  Melting-point  130° 
to  132°. 

The  right  rotation  observed  by  Clergets  has  been  confirmed 
by  Sohst  and  Tollens.4  The  latter  found  that  aqueous  solu- 
tions of  the  anhydride  exhibit  increased  rotation  ;  but  if  the 
saccharic  acid  is  thrown  out  from  its  solutions  by  aid  of  acids 
the  phenomenon  of  decreasing  rotation  is  noticed.  In  both 
cases  a  constant  value  of  about  22.5°  is  reached,  in  the  one 
instance  by  a  gradual  decrease,  and  in  the  other  by  a  gradual 
increase  in  rotation.  See  §75. 

The  observations  of  Sohst  and  Tollens  on  the  gradual  change 
of  the  specific  rotation  of  saccharic  acid  have  been  already  given 
in  §75. 

Add  Ammonium  Salt,  NH4C6H9O8. 

Water c       20.029,     [«]/>  =  -f  5.84° 

Multi rotation  could  not  be  detected.5 

The  specific  rotation  of  /-saccharic  acid  has  not  yet  been 

1  Fischer,  Passmore  :  Ber.  d.  chem.  Ges.,  23,  2226. 

Smith  :  Ann.  Chem.  (Liebig),  371,  183. 
'  Compt.  rend.,  53,  343- 
4  Ann.  Chem.  (lyiebig),  345,  9. 
*  Sohst  and  Tollens  :  Ibid.,  345,  15. 


ACIDS  WITH  EIGHT  ATOMS  OF  OXYGEX  571 

determined.     Its  crystalline  potassium   salt,    KC6H,,O0  rotates 
slightly  to  the  left.1 

ISOSACCHARIC  ACID.    Rhombic  crystals.  Melting-point  185°. 

Water-.  />  F?  4.266,     </;"   =  1.01689     t  —  20°     [a]/,  =  —  46.12° 

The  specific  rotation  of  the  aqueous  solution  is  not  changed 
even  after  heating  three  hours  to  200°  to  220°." 

Water />  =  4.7  after  heating,     [a]/)        +  48.93°  :{ 

Isosaccharic  Acid  Diethyl  Ester,  (C2H5).,C6H,OS.  Crystals. 
Melting-point  73°  ;  boiling-point  250°. 

Water c  =--  5,     [<]z>  --=  -  35-5°  4 

Isosaccharic  Arid  Diamide,  CfiHHO-(NH2)2,  Crystals.  Melt- 
ing-point 226°. 

Water ^  =  5,     M/>  =  ~r  7-i6°  4 

NORISOSACCHARIC  ACID,  (C6H10O8).  Calcium  salt  (p  =  5) 
and  HC1.  After  heating  : 

[a]/,  =  +  51.73°  • 

flf-MANNOSACCHARIC  ACID. 

Anhydride,  CfiH6O6  -f-  2H.,O.  Crystals.  Melting-point  1 80° 
to  190°.  In  fresh  aqueous  solution  : 

p  =  3.432,      d  =  1.0176,     t  =  23°,     [a]/>  =  +  201.8°  6 

Mucic  ACID,  (CHOH)4(CO2H)a.  Crystals.  Melting-point 
213°.  This  acid  is  inactive  from  the  symmetrical  arrangement 
of  its  molecule,  and  former  observations  of  rotation  must  be 
referred  to  impurities.7  For  this  reason  the  efforts  of  Ruhe- 
mann  and  Dufton8  to  split  up  the  acid  into  two  active  compo- 
nents by  aid  of  quinine,  cinchonine,  or  strychnine  failed. 

TALOMUCIC  ACID,  C6H10OS.  Microscopic  plates.  Melting- 
point  158°  (with  decomposition). 

For  freshly  prepared  aqueous  solutions,/  =  3.84,  ^= 

1  Fischer  :  Her.  d.  chem.  Ges.,  33,  2621. 

-  Tieniann  and  Haarmann  :  Ibid.,  19,  1260. 

3  Tieniann  :  /bid.,  27,  137. 

4  Tieinann  and  Haarmann. 

5  Tieniann  :  Ber.  d.  chem.  Ges.,  27,  137. 

-  Fischer  :  /bid.,  24,  539. 

7  Fischer,  Hertz:  /bid.,  25,  1247. 

-  J.  Chem.  Soc..  59,  750. 


5J2  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

/— 20°,  [«] />^- about  29.4°.     On  heating  the  solution,   the 
rotation  diminishes  on  account  of  lactone  formation.1 

14.  Acids  with  Nine  Atoms  of  Oxygen 

"-GLUCOOCTONIC       ACID,       CH.,OH(CH.OH)8.COOH  = 
C,H16Oa- 

Anhydride  (From  or-glucoheptose),  CH14OS.  Melting- 
point  145°  to  147°  (uncor.). 

Water-.  />  =fc  10.405,     d       1.0417,     /       20°,     [a]/,  ==  -j    45.9°  - 

yfl-GLUCOOCTONic  ACID. 

Anhydride,  By  product  in  the  formation  of  the  <r-acid. 
Crystals;  melting-point  186°  to  188°  (uncor). 

Water p -—  1 1.399,     d  —  1.042,    t       20°,      [«•]/>  :=  -j-  23.6° 

The  rotation  remained  unchanged  after  twelve  hours. :! 

rt'-MANNOOCTONIC  ACID,  C^H]6O9. 

Anhydride,  C8HUOM.  From  mannoheptose.  Crystals  ;  melt- 
ing-point 167°  to  170°. 

Water-,  p       9.8534,  J*>  =  1.0394,  t  ±  20°,   [a\D  43-58°  4 

RHAMNOOCTONIC  ACID,   CH3(CH.OH)..COOH  =  C,,HlwOy. 

Anhydride,  C,H16O8.    From  rhamnoheptose.    Needles.    Melt- 
ing-point 171°  to  172°. 
Water..  />  =  4.762,  d         1.0163,  t  —  1.0163,  '  ^  2O°»  [«]/>        -  5O-8°  s 

GALAOCTONicAcio,  lactone,  C8HI4O,.  Melting-point  220° 
to  223°. 

P  —  4.26,       rf  =  I.OI7,       t  ~  20°,       [O-]/,  =   -     64.0°  (1 

"-PENTOXYPIMELIC  ACID,  COOH(CH.OH)..COOH  — 
C.H12O9.  From  <r-glucoheptonic  acid. 

The  anh>'dride  C7H10OM  is  inactive  in  10  per  cent  aqueous 
solution*7 

)8-PENTOXYPiMELic  ACID.     From  /^-glucoheptonic  acid. 

1  Fischer  :  Bcr.  d.  chem.  Ges.,  34,  3622. 

-  Fischer  :  Ann.  Chem.  (Liebig),  370.  92. 
:t  Fischer  :  Ibid.,  370,  100. 

4  Fischer,  Passmore :  Her.  d.  chem.  Ges.,  33,  2233. 
} •i-.cher,  Piloty  :  Ibid.,  33,  3109. 

•  Fischer:  Ann.  Chem.  (Iviebig),  388,  149. 

<-r  :  Ibid.,  27 • 


ACIDS  WITH  TEN  ATOMS  OF  OXYGEN  573 

Anhydride,  CTH1((O,.     Crystals.     Melting-point  about  177°. 
Water />       9.972,  d  =  1.0433,  t       20°,   [a]/)  —  68.5°  l 

TANNIC  ACID,  TANNIN,  CUH10O9  -f  2H..O. 

Water  .  - .  p  —  i,     t       20°,     aD  (for  2  dm.)  1.50°  (?)- 

This  acid  was  formerly  supposed  to  be  inactive,  but  Giinther 
and  also  H.  Schiff  :<  recognized  it  as  strongly  right  rotating. 
The  latter  found  for  pure  commercial  preparations  in  aqueous 
solutions  with  c  =  i,  a  rotation  varying  from  [<*]/,  =  ;  -f  14° 
to  -f  67°  for  different  preparations.  This  stands  in  contra- 
diction to  the  constitutional  formula  proposed  by  Schiff  for 
tannin,  according  to  which  there  is  no  asymmetric  carbon  atom 
present,  and  which  is  supported  by  the  fact  that  the  synthetic 
tannin  obtained  from  gallic  acid  is  optically  inactive,  also  by 
the  fact  that  the  products  obtained  from  natural  tannin  by 
hydrolysis  with  weak  hydrochloric  acid  (gallic  acids)  are  like- 
wise inactive.  To  clear  up  this  point,  Wai  den*  has  under- 
taken some  experiments  on  the  separation  of  different  compo- 
nents from  commercially  pure  tannin  ( (/*J />  = : -f-  67.5°, 
in  water,  c  =  i )  by  means  of  dialysis,  and  also  by  fractional 
precipitation  from  solutions  in  ethyl  acetate  by  addition  of  ben- 
zene, etc.  By  such  methods  he  found  it  possible  to  sepa- 
rate the  tannin  into  fractions  with  unequally  strong  rotations. 
Walden,  therefore,  considers  it  probable  that  the  rotating  powrer 
of  the  natural  tannin  is  due  to  admixture  with  small  amounts 
of  highly  active  substances  of  unknown  composition. 

Rosenheim  and  Schidrowitz5  have  also  examined  the  acid 
anew  and  come  to  conclusions  somewhat  opposed  to  Wai- 
den's.  They  conclude  that  the  larger  portion  of  the  commercial 
acid  is  a  single  homogeneous  body  of  high  rotation,  and  that 
the  formula  of  Schiff  must  be  wrong. 

15.  Acids  with  Ten  Atoms  of  Oxygen 

<*-GLUCONONONIC  ACID,  C9H,HO10.     From  tf-glucooctose. 
Anhydride,  C9H16O9.     Has  not  been  obtained  crystalline. 
Water c  •-—  about  10,     t  —  20°,     [a]/?  =  -f  33°  fi 

1  Fischer  :  Loc.  cit. 

-  Giinther  :  Ber.  d.  deutsch.  Pharm.  Ges..  5,  297,  1895. 
«  Chem.  Ztg.,  (1895),  p.  1680;  (1896),  p.  865. 

4  Ber.  d.  chem.  Ges.,  30,  3151  (1897). 

*  J.  Chem.  Soc.,  73,  878. 

15  Fischer  :  Ann.  Chem.  (Liebig),  370,  102. 


574  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

</-MANNONONONIC  ACID,  C9H18Oi0.     From  mannooctose. 
Anhydride,  C9H16OH.     Crystals  ;  melting-point  175°  to  177°. 
Water  ...........   £--10.002,     /  -----  20°,     {_cc\D  —    —  41.0°  l 

16.  Oxyaldehydes,  Aldoses,  Aldehyde  Sugars 

ARABINOSE,  CHO.(CH.OH)3.CH2OH  ==  C5H10O5. 
d-Arabinose.     Formed  by  degradation  of  ^-glucose.     Rhom- 
bic crystals. 

Water  .....  p=  lo.ir,  d'M  =  1.0402,    t  =  20°,  [«]/>  =  —  104.1° 

Compound  of  d-Arabinose  with  Acetamide,  CH2OH. 
(CHOH)3CH(NH.C2H30),.  Fine  white  needles;  melting- 
point  187°. 

Water  .....  p  .—  10.03,  ^20  =  i-O455>  '  =  2O°.   [**]/>  -    —  9.5°  2 


l-Arabinose.  From  cherry  gum,  exhausted  beet  cuttings, 
exhausted  beermash,  wheat  bran,  gumarabic,  gum  tragacanth, 
quince  mucilage,  gedda  mucilage,  etc.  Glittering  trimetric 
prisms  ;3  melting-point  160°  ;4  152°  to  153°  ;5  158°  to  i6o°.6 

Water  .....  c  —  10,  t  —    5°,  [or]  D  =  -f  104.4°  7 

Water  .....  c  =  10,  t  =  18,  "       =  +  104.4°' 

Water  .....  £=10.369,  *  =  20,  "  =+105.4°,     [a]y=  +  ii809 

Water  .....  c=    8.740,  "  =  -f-  105.1°  10 

Water  .....  c  =-    9.730,  /  =  20,  =  -f  104.55°  n 

Water  .....  c—  10.201,  t  =  20,  "  =  +  104.64°  n 

Water  .....  c=    9.016,  /  =  20,  "  =  -f-  103.87°  12 

/-Arabinose  exhibits  the  phenomenon  of  multirotation.  The 
beginning  rotation  for  c  =  9.73  is  about  157°.  13  See  §72. 
Ammonia  immediately  destroys  the  multirotation.14  The  rota- 

Fischer,  Passmore  :  Her.  d.  chem.  Ges.,  33,  2236. 

Wohl  :  Ibid.,  a6,  740. 

O'Sullivan  :  J.  Chem.  Soc.,  45,  41. 

Scheibler  :  Ber.  d.  chem.  Ges.,  i,  108  ;  v.  I^ippmann  :  Her.  d.  chem.  Ges..  17,  2239. 

Frankland,  MacGreger  :  J.  Chem.  Soc.,  61,  737. 

Conrad,  Guthzeit  :  Ber.  d.  chem.  Ges.,  18,  2907. 

Bauer  :  Ibid.,  33,  Ref.  835. 

Scheibler:  Ibid.,  17,  1731. 

v.  I^ippmann  :  Ibid.,  17,  2239. 

10  Kiliani  :  Ibid.,  19,  3031. 

11  Parcus,  Tollens  :  Ann.  Chem.  (lyiebig),  357,  173. 

12  Allen,  Tolleus  :  Ibid.t  360,  300. 
18  Parcus  and  Tollens  :  Loc.  cit. 

11  Schulze,  Tollens  :  Ann.  Chem.  (Uebig),  371,  49. 


OXYALDEHYDES,  ALDOSES,  ALDEHYDE  SUGARS 


575 


tion  decreases  with  increasing  temperature.     For  example  : 

[flr]#    -  +  106.0°,  [«]£  =  -  104.5°  l 

Arabinosazone,  C3HBO3(N.NHC6H5).,.  Crystals  ;  melting- 
point  157°  to  158°  ;2  159°. 

Alcohol,  95  per  cent. c  =  3.40,     t  =  20°,     [«]/>  =  +  18.90° 

The  rotation  gradually  disappears.*     Compare  Fischer.5 

i-Arabinose.  An  aqueous  solution  which  contained  10  per 
cent,  of  each  of  the  active  components  rotated  in  a  i  dm.  tube, 
after  fifteen  minutes,  4°  to  the  right  ;  after  one  hour  -f-  0.2°, 
and  after  two  hours  it  was  inactive.  Wohl6  refers  this  to  the 
birotation  of  the  /-arabinose. 

XYLOSE,  CH,OH(CHOH)3CHO  =  C6H10O6.     White  needles 
or  orthorhombic  prisms  ;  melting-point  144°  to  145°. 
Water  .  -  c  =  10.664,  t  =  20°,  \_oc]D=  -f  19.31°  \" 

Water..   £=11.070,  /  =  20,         "    =  -f  19.22    ( 

Water..  c=  10.108,  /  =  22,         "    =+19.39 

Water  ..  /=    9.940,      d™  =  1.0359,     t  =  20°,     !>]/>  +  18.99°  8 
(Mean  of  about  50  readings.) 

The  effect  of  concentration  on  the  specific  rotation  of  aqueous 
solutions  of  xylose  was  investigated  by  Schulze  and  Tollens.* 
All  the  solutions  were  tested  after  standing  twenty  to  twenty- 
four  hours,  the  61  per  cent,  solution  after  a  quarter  of  an  hour. 


>• 

d?. 

My- 

3.115 

[.00977  • 

-f  18.425° 

5.376 

.01814 

18.547 

9.706 

.03481 

18.773 

21.744 

.08299 

19.610 

34.355 

•13750 

20.495 

46.395 

.19266 

21.429 

56.229 

.24205 

22.681 

61.747 

.27258 

23.702 

Parcus,  Tollens. 

Scheibler. 

Allen  and  Tollens. 

Allen  and  Tollens:  Ann.  Chem.  (I^iebig),  260, 

Fischer  :  Her.  d.  chem.  Ges.,  23,  385,  note. 

Ibid.,  26,  740. 

Parcnsand  Tollens  :  Ann.  Chem.  (Uebig),  257 

Wheeler.  Tollens  :  /bid.,  254,  310. 

/bid.,  271,  40. 


300. 


175. 


576  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

From  these  figures,  interpolation  formulas  for  the  tempera- 
ture of  20°  may  be  calculated  : 

I C=;    31034,     [ a] />  ---  18.095  +  0.06986 />, 

II ^-^341061,  -  23.089  —  0.1827;!)  +  0.0031 2  A" 

The  temperature  has  no  marked  effect  on   the  rotation  be- 
tween 15°  and  20°,  but  above  20°  a  change  takes  place  which 
must  be  considered  in  any  exact  investigations. 
Water p  =-  10.0829,     d™  —  1.0362 


-f  18.898° 

20  18.909 

25  19.248 

30  19.628 

I 

Xylose  exhibits  multirotation.      §72. 

Observations  of  Wheeler  and  Tollens1  gave  : 

Water  . .  c  ~  10.236,     t  c=  20°,  after    5  minutes  [«]/>  =i  -f-  85.86° 

Water-,  c  =  10.236,     ^=20,       "      10        "  =  +  70.14 

Water  ..  £=  10.236,     t  =  20,       "      16  hours  constant       "    -  -  -f  18.59 

Parcus  and  Tollens2  found  the  beginning  rotation  lower  : 

Water C=  10.664,     t  =  20°      after    5.1  minutes  [a]D  =  -f  77.87° 

constant       "     24    hours  =  -f  19.31 

Water r       11.070,     /  =  20°,        "       4^  minutes       "    -  =  -f  78.61 

constant       "     24    hours  =  -f-  19.22 

From  this  [«]/>  two  tninutes  after  solution       about    91° 
"         "         "     immediately     "  about  100 

Ammonia  of  about  o.  i  per  cent  strength  brings  about  the 
end  rotation  immediately.  If  more  than  o.  i  per  cent,  is  pres- 
ent the  rotating  power  is  very  greatly  decreased.  See  §73." 

Xylosazone,     C5H8O3(NaH.C6H5)2.        Bright     yellow     silky 
needles;  melting-point  159°  to  160°. 
Alcohol,  95  per  cent. p       2.815,     d      °-85,     [<*]/>        ~  43-36° 

After  more  than  a  week  the  solution  showed  approximately 
the  same  end  rotation.4 

1  Ann.  Chem.  (I,iebig),  354,   311. 

*  Ibid.,  357,  175. 

"  Schulze,  Tollens  :  Ibid.,  371,  49. 

*  Allen,  Tollens:  Ibid.,  360,  295. 


OXYALDEHYDES,  ALDOSES,  ALDEHYDE  SUGARS     577 

FUCOSE,  CH3.  (CHOH)4CHO  ==  C6HWO5-  Fr<>m  s^a  weeds. 
Crystals;  melting-point  116°  to  140°. 

Water..  £  =  9.1375  (dried  at  65°),     /  ^  20°,     [«!/>=    —75.96° 
Fucose  shows  marked  multirotation.     An  aqueous  solution 
clarified  with  alumina  cream  gave  the  following  rotations:1 
c  =  6.9155,     /  —  20°,  after    n  minutes  [a~\D  =  —  111.8° 
"        14         "  106.8 

"  21  "  97.8 

31  "  90.0 

71  "  79.0 

ioi         "  77.8 

"         146  "  76.8 

On  the  following  day  constant  =     -    77.0 

RHAMNOSE  (Isodulcite,  rhamnodulcite),  CH3.(CHOH)* 
CHO  +  H20  =  C6HU05  +  H20. 

Ordinary  Rhamnose.  Monoclinic  crystals ;  melting-point 
93°  to  94°.  (On  the  three  modifications  of  the  substance,  see 
§72.)  The  following  numbers  hold  for  the  final  constant 
rotation  and  the  hydrate  : 

From  quercitrine,   water c  =  18.076,     t  =  17°,     [a]^  =  -J-  8.04°  2 

From  xanthorhamnine,  water  c  •—  26.04,  t  =  17°,  [«]z>  =  -f  8.07°  3 
From  xanthorhamnine,  water  c  =  12.390,  /  —  18°,  [«]/>  =  -j-  8.83°  4 
From  naringenine  (citrus  decu- 

mana)  water <:=25.i66,     t=ij°,     [a]n  =  -+-  8.2°  5 

Effect  of  concentration  : 

c  =          5  9  18  22  40 

[a]/,  =  H-  8.48°,     +  8.52°,    +  8.50°,     +  8.51°,     -  8.65° 

The  rotation  is,  therefore,  influenced  but  little  by  the  con- 
centration. With  elevation  of  temperature,  the  rotation  de- 
creases and  vice  versa.  For  /  —  6°  to  20°  this  formula  holds  : 
[<*]/>  =9.18°  —  0.035  /6 

Rhamnose  exhibits  multirotation  as  described  in  §72. 
Freshly  prepared  solutions  show  left  rotation  which  changes 
gradually  to  right  rotation  : ' 

1  Giinther.  Tollens  :  Ann.  Chem.  (I^iebig),  371,  86. 

'-  Berend  :  Ber.  d.  chem.  Ges.,  n,  1354. 

a  Liebermann,  Hormann  :  Ibid.,   n,  956;  Will :  Ibid.,  ao,  1186. 

*  Stohmann,  I«angbein  :  J.  prakt.  Chem.,  [2],  45,  308. 

'•>  Will  :  Ber.  d.  chern.  Ges.,  20,  294. 

6  Schnelle,  Tollens  :  Ann.  Chem.  (l,iebig),  27i,  62. 

'•  Jacobi:  Ibid..    272,  175. 

37 


578  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Water p  -     10,     df  =  J  -O236>     '  r     2O° 

After   i  minute O]/1        -  5-6° 

After  8  minutes "  o.o 

Constant  after  i  hour "  8.3 

Water c       TO,     /       19.51020.5° 

After  5 i  minutes [«]/>"    —  3-ii° 

After  9£  minutes "  o.o 

Constant  after   57  minutes "       =  +  8.56 

In  another  series  of  experiments,  the  beginning  rotation  was 
-4-5°.' 

The  decrease  in  rotation  takes  place  regularly  with  gradually- 
diminishing  rapidity.2 

When  rhamnose  is  heated  to  the  melting-point,  the  end  rota- 
tion is  reached  immediately/ 

A  small  addition  of  ammonia  destroys  the  multirotation.4 

Water,  c       10.052  /  =  20°,  [a]/)  after  20  hours  =  -+-  7.86° 

Water  with  o.i  per  cent  ammonia,  t  —  20°,  [<*]/.> after    7  min.    ==-f  7-95 

For  further  observations  on  rhamnose  see  Gerne/.1  and 
Tanret." 

On  the  rotation  of  rhamnose  in  alcoholic  solution,  see  §64. 

Anhydrous,  Amorphous  Rhamnose,  Isodulcitan,  CHHK,O-. 

Water p       9.238,     d^     1.0281,     /       20°,     [>]/,     =-{-8.7° 

This  shows  no  multirotation  in  water  solution  :! 

Water />       27.982,     d'*  1.1002,     /  20°,     (>]/>  -j     6.36° 

Water />       21.519.       "  1.0765,     /  20,  =+    9.43 

Water />     -14.419,      "  ^1.0507,     /  20,  s'+    9.34 

Methyl  alcohol   (97.94  p.  c.), />  19.06,^"  0.8842,  [a ]/>  -10.59 

In   alcoholic  solution  the  rotation   may   be  either  -j-  or 
according  to  the  concentration  and  the  percentage  of  water  in 
the  alcohol.     Ray  man  and  Kruis7  obtained  the  following  num- 
bers : 

1  Schnelle  and  Tollens  :  IMC.  at. 

*  I'arcus  and  Tollens  :  Ann.  Cheni.  (Iyiebig),  257,  160. 

*  Jacobi. 

*  Schul/.e,  Tollens:  Ann.  Chem.  (I^ebig),  371,  49. 
•'•  Compt.  rend.,  121,  1150. 

••  //>/</.,  laa,  86. 

:  Bull.  soc.  chim..  [2],  48,  635. 


OXYALDEHYDES,  ALDOSES.   ALDEHYDE  SUGARS  579 

Ethyl  alcohol  (  5.31  p.  c.),  p       17-579,  d"4"       LO534,    O]/>  =   J      8.96° 

"       (10.91   "")  16.694  1.0432  -f    8.18 

"       (29.84  "  "  )  -17.690  1.0170  4.14 

"       (43-57  "  "  )  18-621  0.9960  3.28 

"       (38.27  "  ")  11.177  0.9767  2.35 

"       (66.09  "  "  )  12.669  0.9482  0.84 

(94.00  "  "  )  10.445  0.8502  9.23 

(96.11  "  "  )  7.028  0.8292  -  10.04 

"       (97-36"")  4-875  0.8159  -10.69 

"       (99-33  "  "  )  9-368  0.8176  -  10.65 

Rhamnose  Oxime,  C6H,,O4:NOH.  Crystals  ;  melting-point 
127°  to  128°.  Does  not  show  multirotation.  See  §72. 

Rhamnose  Phenylhydrazone ,  C6H12O4.  ( N2H . C6H5) .  Colorless 
scales  ;  melting-point  159°.  Dissolved  in  water  by  gentle  heat 
and  quickly  cooled: 

p     -  i. oil,     d*'     =  1.0091,     /       20°,     [a]/>  =         54-3°  ' 

It  does  not  show  birotation.  The  rapidity  of  hydrazone 
formation  may  be  followed  by  the  polariscope.' 

GALACTOSE,  (Lactoglucose),  CH.,.OH.(CH.OH)4.CHO. 
d-Galactose.     Found  in  three  modifications.     See  §72. 
Ordinary  Galadose.     Granular  crystals  ;  melting-point  1 68°  ;3 
161°  to  162°  ;4  162°. :> 

For  the  constant  form  there  has  been  found  : 
Water,  c        10  to  15°,     [a]/>  ~-  81. 4  to  81.7°  '' 
Water,  p       10,     dts        1.0385,     /  =  18°,     [«]/>  81.2°  T 

Water,  c       9-973,     t       *5°<     [<r]/.  -=  +  81.01°  * 
Water,  p  . -.-.  10.182.     d*'        1.0395,     t       20.5°,     [cr]/,    -: - --   80.5     ' 
Water,  p        10,  d*"       1.0379,   f       20°,    [n-] />•---  — 8i.5°,;[<v]  /       -    92.0°  10 

From  /f-galactan  : 

Water c        10.078,     /        15°,    [a]/,  -     —  81.54°  1! 

For  the  dependence  of  the  specific  rotation  of  aqueous  solu- 

1  Fischer,  Tafel  :  Ber.  d.  chem.  Ges.,  20,  2574. 
-  Jacobi  :  Ann.  Chem.  (Liebig),  272,  174. 

v.  Lippmann  :  Ber.  d.  chem.  Ges.,  18,  3335. 

Miintz  :  Jahresber.,  1882,  p.  1125. 

Schulze,  Steiger  :  I<and.  Vers.  Stat.,  36,  423. 

Kent,  Tollens:  Ber.  d.  chem.  Ges.,  17,  668. 

Scheibler  :  Ibid.,  17,  1731. 

Steiger  :  Ztsch.  physiol.  Chem.,  n,  373. 

Tollens,  Stone  :  Ber.  d.  chem.  Ges.,  21,  1573. 

v.  Lippmann  :  Ibid.,  17,  2239. 

Schulze.  Steiger:  Land.  Vers.  Stat.,  36,  423. 


580 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


tions  on  the  percentage  strength  and  temperature,  Meissl  has- 
found1 

[«] D  =  83.883  +  0-0785  P  -  0.209 ', 
which  formula  holds  for/  —  5°  to  35°  and  t  =  10°  to  30°. 

Rindell2  gives  the  formula 

[a] '„  ^=83.037   i  o.i99/>    -  (0.276  —  0.0025  p)  /, 

holding  for/  =  11°  to  20°  and  /  =  4°  to  40°. 

The  two  formulas  lead  to  the  following  specific  rotations  : 


A  


20 


/=  io°      20°      3°°         I0°     20°      3°°        I0°      20°      30° 

(Meissl    82.58  80.49  78-40    82.97  80.88  78.79    83.36  81.27  79.18 
D  I  Rindell  82.52  80.01  77.50    83.64  81.25  78.87     84.76  82.50  80.24 

Galactose  possesses  multi rotation.  For  the  beginning  rota- 
tion Meissl  found  130°  to  140°,  v.  L,ippmann  134.5°,  Koch^ 
132.5°,  133.8°,  137.4°.  Parcus  and  Tollens4  give  the  follow- 
ing observations  : 


£  =  11.0810.    /  = 

=  20° 

C  =  10.2045.      /  =  2C 

)°. 

Time  after  solution. 

r«]«. 

Time  after  solution. 

[«]/.. 

117  27° 

117  48° 

8         •«       

1  16  14 

Q             «« 

1  16  47 

1  14  27 

JQ                      "                 

1  14  41 

20         "       

IO7  71 

10         " 

AVJ/./l 

IO2  87 

70                " 

QQ    Qr 

3° 

oS    77 

50         "       

95  88 

1°                 

9°.  33 
94  26 

8 

S      H 

4        " 

81  02 

7            «          

Si    7.7 

"OU 

1 

80  27 

6     ••      ^ 

80  70 

24      "      )   ' 

4  ••  i 

00.39 

! 

1  J.  prakt.  Chem.,  [2],  23,  97. 

»  Scheibler's  N.  Z.  Rbz.-Ind.,  4,  170. 

»  Pharm.  Ztg.  f.  Russl.,  1886. 

<  Ann.  Chem.  (I4iebig),  357,  168. 


OXYALDEHYDES,  ALDQSES,  ALDEHYDE  SUGARS  581 

From  the  curve  constructed  from  this  we  have : 

[  a]  r>  after  2  minutes  =  about  122° 

"  at  moment  of  solution  =       "      127° 

o.i  per  cent  ammonia  destroys  the  multirotation.1 

d-Galactose  Oxime,  C6H12O5:NOH.     Crystals  ;  melting-point, 
175°  to  176°.     Multirotation  shown. 

Water p  =  5.1056,     rf~  =  1.017,     /  =  20° 

After  10  minutes [  oC\r>  —  +  20.6° 

"     20  hours  constant "       -+14.75 

On  account  of  the  slight  solubility  in  cold  water,  solutions 
up  to  a  strength  of  5  per  cent,  only  could  be  investigated.2 

d-Galactose Phenylhydrazone,  C6H12O5:(N2H.C6H5).  Crystals; 

melting-point,  158°. 

Dissolved  by  aid  of  gentle  heat  in  water  and  quickly  cooled : 
p  =  1.980    d™  =  1.0065,    t  =  20°,    [a]/>  =  -  21.6° 

Multirotation  could  not  be  observed.3     See  also  Fischer  and 
Tafel.4 

d-Galactose  Anilide,   C6HnO5.NH.C6H5.     Triclinic  crystals  ; 
melting-point  about  147°. 

Ethyl  alcohol  (90  vol.  per  cent.)  : 

p  =  2.289,     ^-  =  0.8366,     ^  =  20°  to  23°,     [a]0  =    -31-33° 
p  ==  2.099,      "    ==  0.8334,     t  =  20°  to  23°,  -  31.44° 

Methyl  alcohol  (4^°  =  0.7907^; 
^  =  1.699,     d?  =  0-7997,     /  =  20°  to  23°,     [<*]/>  =    -  33-I2° 

d-Galactost-p-toluide,     C6H11O6.HN(CH1).C6H4.       Crystals ; 
melting-point,  139°. 

Methyl   alcohol  (as  above)  : 
p  =  0.6167,     ^4°  =  0.7952,     t  =  20°  to  23°,     [a]/,  =    —  33.99° 

Ethyl  alcohol  (50  per  cent.)  : 
p  =  0.9832,     d™  —  0.9316,     t  =  20°  to  23°,     \oi\D  -     -  10.91°  5 

d-  Galactose  Pentaacetate -,  C6H.O6(  C2H3O)5.     Glistening  rhom- 
bic plates  ;  melting-point,  142°.     Right-rotating.6 

l-Galactose.     Formed  in  the  fermentation  of  z'-galactose  by 

1  Schulze,  Tollens:  Ann.  Chem.  (Liebig),  271,  49. 
-  Jacobi :  Ber.  d.  chem.  Ges.,  34,  698. 

3  Jacobi  :  Ann.  Chem.  (Liebig),  272,  173. 

4  Ber.  d.  chem.  Ges.,  20,  2568. 

5  Sorokin  :  J.  prakt.  Chem.,  [2],  37,  295  and  309. 

6  Fudakowsky  :  Ber.  d.  chem.  Ges.,  u,  1071 


582  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

beer  yeast.     Crystals  ;  melting-point,   162°  to  163°  (not  cor.). 
Exhibits  multirotation. 

Water  ..........   c       10;     [<*]/>  after  8  minutes        —120° 

"      constant  73-6° 

These  values  may  be  looked  upon  as  approximate  only  as 
the  preparation  used  was  not  sufficiently  pure.1 

SORBIN     (Sorbinose,      sorbose),      CH2OH.(CH.OH);rCO. 
CH2OH.     Rhombic  crystals. 

Water  ..........   c       23,  OL        —46.9°- 


Shows  no  birotation. 
GLUCOSE  (Glycose). 

d-Glucose  (Dextrose,  grape-sugar,  starch  sugar),  CH2OH. 
(CHOH)4CHO  +  H,O.  On  the  three  modifications  of  ^-glucose 
see  §72,  p.  260. 

Ordinary  Glucose.  Hydrate  d  :  monoclinic  crystals  ;  anhy- 
drous :  rhombic  hemihedral.  The  constant  specific  rotation 
of  </-glucose  has  been  determined  by  many  observers.  The 
most  reliable  determinations  in  respect  to  purity  of  substance 
as  well  as  to  accuracy  in  measurements,  are  those  of  Tollens,4 
and  they  have  shown  that  the  specific  rotation  increases  to  an 
appreciable  extent  with  the  percentage  amount  of  glucose  p 
in  the  solution.  The  increase  may  be  expressed  by  the  follow- 
ing formulas"'  which  hold  from  the  weakest  to  the  strongest 
solutions  : 

I.  Anhydrous  Glucose,  C6H12O6.     t  ==  17°  : 

O]/>       52.50  ~j   0.018796  />  r  0.0005  1683  />-' 
59.55  —  0.12216    q  -f-  0.0005168   q* 

II.  Hydrated  Glucose,  C.HWO.  +  H2O  : 

M"       47-73  +  0.015534  p  -f  0.0003883  pl 

According  to  this,  we  have  the  following  specific  rotations 
for  solutions  containing  different  amounts  of  anhydrous  glu- 
cose : 

1  Fischer,  Hertz  :  Ber.  d.  chem.  Ges.,  35,  1247. 

•  Berthelot  :  Ann.  chim.  phys.,  [3],  35,  222. 

*  Wehmer.  Tollens:  Ann.  Chem.  (I,iebig),  243,  320. 
4  Ber.  d.  chem.  Ges.,  9,  487,  1531  ;  17,  2234. 

'   I  hid.,  17,  2238. 


OXYAUDEHYDES,  ALDOSES,  ALDEHYDE  SUGARS 


583 


10 

15 

20 

25 

30 

52.74 

52.90 

53-08 

53-29 

53.53° 

40 

50 

60 

70 

80 

54.08 

54.73 

55-49 

56.35 

51-31° 

and    the   reply    of 


[a]/,       52.61 

/>          35 
!>]/>        53-79 

Compare  with  reference  to   this,  Ost, 
Tollens.' 

Solutions  freshly  prepared,  without  heat,  show  birotation 
(see  §72).  Among  the  many  experiments  on  the  change  in 
the  rotation  of  glucose,  it  will  be  sufficient  to  quote  those  of 
Parcus  and  Tollens  as  the  most  exact.'  These  were  made 
with  glucose,  prepared  according  to  Soxhlet's  method  from 
cane-sugar,  and  dried  at  60°  to  70°. 


/  =  20°,      C  =  9.0970. 

t  =  20°,      C  =  5.5255- 

Time  after  solution. 

' 

Time  after  solution.                  [fO^- 

rr^c   T£° 

i  mimit*»c.  .                                           ir\A    "y(-\° 

sVi 

minutes  105.  16°         7  minutes  .  .  . 

104.26° 

61 

, 

"       104.59           8         "       ••• 

103.64 

10 

101.55           9         "       ... 

103.01 

12 

"       100.03         I0         " 

102.38 

U 

>l       97-94         12         "       ... 

101.13 

20 

"       92-42         13         "       •••• 

100.50 

30 

83.86         14         "       ... 

99-88 

50 

72.26         15         "       ... 

98-63 

I 

hour  68.27         25 

92-35 

I1 

4 

hours  63.33         3°         " 

88.61 

[' 

1 

"     59.71           i  hour  

73.58 

6 

%'      constant.-         52.49           7  hours,  constant  52.60 

The  end  rotation  appears  immediately  when  the  glucose  has 
been  heated  to  melting/  or  when  the  solution  is  heated  for 
some    time.1     The    addition    of    o.i    per  cent,    of   ammonia 
destroys  the  multirotation,"  but  if  more  ammonia  is  added  the 
specific  rotation  is  much  decreased. 
c  —  about  10,     /  =  20°  :  Directly  after  solution  .........    [a]/>        49.82° 

'  '  50.00 
'*  =  49.65 
"  46.36 


After  30  minutes 
After    i1  .,  hours 
After  24  hours 
1641. 


1  Ber.  d.  chem.  Ges  ,  24 

-   Ibid.,  24,  2000. 

3  Ann.  Chem.  (Uebig),  257,  164. 

•»  Schmidt  :  Ibid.,  119,  95. 

;'  Hesse  :  Ibid.,  192,  172. 

';  Schulze  and  Tollens  :  Ibid.,  271,  49. 


584  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Influence  of  Inactive  Substances  on  the  Rotation  of  Glucose 
Pribram1  has  determined  the  effect  of  addition  of  the  follow- 
ing substances  on  the   specific  rotation  of  glucose,    the  end 
rotation  reached  in  each  case  after  long  standing  being  finally 
measured  : 

1.  Ammonium  Carbonate. 

Solutions  which  contained  in  100  cc.  16.46  grams  of  anhy- 
drous glucose  and  p  grams  of  the  salt  gave  : 

/>  o  2  46  8  10 

[<*]£=  52.83      52.40      52.22      51.36      51.11      50-85° 
There  is,  therefore,  a  slight  decrease  in  the  specific  rotation 
of  the  glucose. 

2.  Urea. 

The  solutions  contained  in  100  cc.,  15.797  grams  of  anhy- 
drous glucose  and  p  grams  of  urea  : 

P  —-.    o  4  8  12  16 

[a]£  -  52.91        52.84       52.61        52.23       51.95° 
There  is  also  here  a  decrease  in  the  specific  rotation,  but 
it  is  slight.    According  to  Neumann  Wender,2  neither  urea  nor 
any  other  substance  in  urine  has  any  effect  on  the  rotation  of 
glucose. 

3.  Acetone. 

The  solution  contained  in  ioocc.,  15.  68  grams  of  anhydrous 
glucose,  c  grams  of  acetone  and  water  : 

r          o  4  8  12  16          20          24         40         50 

[or]»       52.89     53.29     53.63     53.94     54.23     54.53     54.81     56.19     57-03° 

The  specific  rotation  of  glucose  increases  in  rather  marked 
degree  with  increase  in  the  acetone  content  of  the  solutions. 

Alkalies  and  also  lime  bring  about  a  gradual  decrease  in  the 
rotation,  and  its  final  disappearance  by  decomposition  and 
production  of  salts  of  saccharinic  acid  (left-rotating),  glucinic 
acid,  and  humus-like  bodies. 

Derivatives  of  ^/-Glucose 
Glucoseamine 


1  Sitzungsber.  d.  Wien.  Akad.,  p7,  II  375. 
*  Ber.  d.  chera.  Ges..  24,  2200. 


DERIVATIVES   OF   </-GLUCOSE.  585 

COH.HC1.      Monosymmetric  crystals.      From  lobster  shells. 

Water p    -5.158,     </»-:  1.01865,     /  ^  20,     [»  =  + 74.64' 

"     p       2.593,        "  :      1.00853,     t-=20,         "       =  -f  70.61 

Glucoseamine    Hydrobromide,     C6H13NO5.HBr.       Monosym- 
metric crystals. 

Water p       22.555,     ^=1.1146,     t  =  20°,     [a]/,  =  59-37° 

"     p       12.505,       "    =  i.  0601,     t=20,  =  59.63 

"      P         5-312.       "    =1.0237,     *  =  2o,  =60.23 

The  specific  rotation  increases  therefore  with  the  dilution 
according  to  the  formula : 

[«]/'     55-21  -  0.053  q- 

Glucoseoxime ,    C6H12O3:NOH-      Colorless  prisms;   melting- 
point,  136°  to  137°  ;3  135°- 4     Shows  multirotation. 

Water p  ~-  9.367,     d  =  1.0295,     t  =  20°  i  5 

[a]/)  after  15  minutes =  —  5.5  \ 

"       "      1 8  hours,  constant =     —  2.2  J 

Glucose  Trisulphuric  Acid,  C6H9O3(HSOJ3. 

Water £=11,     \a\D  =  +  43-2°  6 

Glucose     Tetrasulphuric    Acid    Chloride,     C6H.OC1(HSO4)4. 
Square  prisms. 

Water £--^4.4,     [a]/)^=  +  71.8°  7 

Acetochlorhydrose       (  Glucose-monochlorhydrin-tetracetate ) , 
C6H7(C2H30)A-C1. 

Acetonitrose(  Glucose-  tetracetate-mononitrate ) ,  C6H.  ( C2H3O )  4. 
XO3.O5.     Crystals  ;  melting-point,  145°. 

[«]/=+ i59°  9 

Octacetyl  Diglucose,  CiaHu(C2H3O)  Ai- 
I.   Crystals:  melting-point,  39°  to  40°. 

Water /  =  16°  to  17°,     [a]/)  =  +  54-62°  10 

Wegscheider:  Ber.  d.  chem.  Ges.,  19,  52. 

Tiemann,  I^andolt :  Ibid.,  19,  155. 

Jacobi. 

Wohl :  Ber.  d.  chem.  Ges.,  24,  995. 

Jacobi :  Ibid  ,  24,  697. 

Claesson  :  J.  prakt.  Chem.,  [2],  ao,  26. 

Claesson. 

Colley  :  Compt.  rend.,  70,  401. 

Colley  :  Ibid.,  76,   436. 

Demole  :  Ber.  d.  chem.  Ges.,  la,  1936. 


586  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

II.  Cauliflower-like  groups  (from  ether)  ;  melting-point, 
128°  to  133°. 

Benzene £—2.415,     [t*]^  = -f  22.50°  ! 

Glucose  Phenylhydrazone,  C6H12O5(N2H.C6H5). 

Exists  in  two  isomeric  forms  ;  the  pure  white  crystals  only, 
with  melting-point  113  to  115,  were  investigated  optically. 
They  show  strong  multirotation. 

p          9.l8l,       d™          1-0257,       t  =  20° 

[<rl/>  after  10  minutes —  15.3° 

"        ".    12  to  15  hours,  constant.         —  46.9 

The  multirotation  is  not  due  to  the  fact  that  the  substance 
had  passed  into  the  isomeric  modification,  because  the  crystals 
again  obtained  from  the  solution  melt  at  114°.-' 

Glucose  Anilide,  C6HnO5-HN.C6H5.  Sheaves  of  needles  ; 
melting-point  about  147°. 

Methyl  alcohol  (^=°       0.7907): 
p  =  5.029,     d™       0.8065,     t       20°  to  23°,     [«]/>  =    —48.32° 

p  3.326,  "     -   .  0.8055,        /  20°   tO   23°,  r-  49.15 

Ethyl  alcohol  of  90  vol.  per  cent.  (d2°      0.8294) : 
P       4-697,     d™      0.8453,     t       20°  to  23°,     [>]/>        -  44.08°)  ! 
p       3-269.  0.8407,     t       20°  to  23°,         "  44-15    j 

Glucose Paratoluide,  C6HUO,.HN.  (CH:!)C6H4  -f  !/,H,O.  Crys- 
tals ;  melting-point,  106°. 

Methyl  alcohol  (as  above)  : 

P       7.879.     d*1      0.8243,     t       22°  to  26°,     [n:]/,^  -43.88° 
p=  4.082,       "       0.8061,     /       22°  to  26°,         "  42.55 

p  —  2.6l3,  "          0.8007,       t          22°  tO  26°,  "  38.23     \ 

Ethyl  alcohol  (as above): 
P       6.658,     d™      0.8513,     t       22°  to  26°,     [>]/,.      -38.80°] 

Glucose  Ethylmercaptal,  C8H12O5(SC2H,),.     Crystals. 
Water p       4.878,     d=°      1.002,     t      50°,     [<r]/>        -29.8°^ 

/-GLUCOSE. 

From  /-gluconic  acid  anhydride.  Crystals  ;  melting-point, 
141°  to  143°. 

1  Herzfeld:  Ann.Chem.  (Iviebitf),  230,  219. 

2  Jacohi  :  I  bid.,  aya,    171. 

3  Sorokin  :  J.  prakt.  Chem.,  [2],  37,  295. 

4  Sorokin  :  I  hid.,  [2],  37,  308. 

6  Fischer  :  Ber.  d.  chem.  r.es.,  37,  675. 


MANNOSE  587 

Water /       4.114,     ^=°-.-i.oi6,     t=-    20°  j1 

[a]/)  after  7  minutes -  94-5  /• 

"     7  hours,  constant -   51.4! 

MANNOSE  (Seminose),  CH,OH.(CH.OH)rCHO.2 
d-Mannose. 

I.  From  mannitol  by  oxidation.     Crystals. 

Water />       about  10,     ^ -.-  1.0416,  /       20°,     [«]/>        r  12.96°  :! 

II.  From  nut  shells  : 

Water c       about  10,     /       20°,     \oi\o       ~   H-36° 

The  small  difference  is  due  to  the  amorphous  nature  of  the 
latter  product.4 

d-Mannose  Oxime,  C6H12O5:NOH.  Crystals;  melting-point 
176°  ;5  176°  to  184°  (not  constant).6 

Exhibits  multirotation.  On  account  of  the  difficult  solu- 
bility, a  5  per  cent,  solution  only  could  be  investigated. 

Water p  =  4.798,     d       1.016,     t   -  20° 

[«]/>  after  10  minutes =  =  4"  7'5 

"       "        6  hours,  constant =-(-3.2! 

l-Mannose.  From  /-mannonic  acid  anhydride.  Sirup. 
In  aqueous  solution  rotates  to  the  left.* 

The  phenylhydrazone,  melting-point  195°,  is  right-rotating 
in  hydrochloric  acid  solution  ;  the  phenylglucosazone,  melting- 
point  205°,  is  strongly  right-rotating  in  glacial  acetic  acid 
solution.9 

RHAMNOHEXOSE,     Methylhexose,    CH3.(CHOH)5.CHO  = 
C7HUO6.   From  rhamnohexonic  acid.     Crystals  ;  melting-point, 
1 80°  to  181°.     Shows  strong  multirotation. 

Water p  =  9.675,     d™  =  1.0347,     '       2O°  ]  10 

After  ]  2  hour [«]/,--     -  82.9  j. 

After  12  hours,    constant "  —61.4! 

1  Fischer  :  Ber.  d.  chem.  Ges.,  23,  2618 
'-  Fischer,  Hirschberger  :  Ibid.,  23,  1155. 
;i  Fischer,  Hirschberger  :  Ibid.,  22,  365. 
4  Fischer  and  Hirschberger  :  Ibid..  32,  3218. 
•"'  Reiss  :  Ibid.,  32,  611. 

6  Fischer  and  Hirschberger:  Ibid.,  32,  1156. 
'  Jacobi  :  Ibid.,  24,  698. 
8  Fischer  :  Ibid.,  33,  373. 
'-'  Fischer. 
10  Fischer,  Piloty :  Ber.  d.  chem.  Ges.,  33,  3102. 


588  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


CH2OH.(CH.OH)5.CHO  -=  C7HUOT- 
From  ar-glucoheptonic  acid.     Rhombic  plates  ;   melting-point, 
1  80°  to  190°.     Shows  weak  birotation.      For  a  solution  made 
by  gently  warming  with  water,   c  =  10,   t  =  20°,  [<*]/?  = 
19.7°  at  once,   and  after  fifteen  minutes  with  greater  dilution 

[«]„  =  -  25°.- 

fi-Glucoheptose,  not  yet  investigated. 

^-MANNOHEPTOSE,  C.HUO.  (at  104°).  Crystals;  melting- 
point,  134°  to  135°  (notcorr.  ).  From  ^-inannoheptonic  acid. 
Exhibits  multirotation. 

Water  ..................  p=  10.807,     d*  =  1.0397,     /  =  20°  1  - 

After  10  minutes  ..........................    [or]  />  =  -f-  85.05  \ 

After  24  hours,  constant  ...................         "    =  -j-  68.64 

l-Mannoheptose,  from  /-mannoheptonic  acid,  could  not  be  ob- 
tained in  a  crystalline  condition,  but  is  characterized  by  its 
phenylhydrazone,  melting  at  196°,  with  complete  decom- 
position.3 

£-GALAHEPTOSE,  C.HUO7.  Melting-point,  190°  to  194°. 
Shows  multirotatiou. 

Water  ......  p  —  9.2,  10  minutes  after  solution  [a]^  =  —  22.5° 

After  24  hours  [«]=£=  —  54.4°  4 

RHAMNOHEPTOSE,     C8H16O7.     From  rhamnoheptonic    acid. 
Water  .......   c   =  9.40,     t  =  20°,     [a]/,  ==  -f  8.4°  (about) 

a-GLUCOOCTOSE,   C8H16Ob  +  2H2O.      From  «-glucooctonic 

acid.     Needles  ;  melting-point,  93°  (uncorr.).  Shows   multi- 
rotation. 

Water  .........  p—  6.496,     d  =  1.0213,     ^  20°  '"'                     • 

Hydrat«d.          Anhydrous. 
After  a  short  time  ..........    [<^]/>  61.5°  70.8° 

After  6  hours,    constant  .....  43.9  50.5 

^-MANNOOCTOSE,  C8H16O8.  From  ^/-mannooctonic  acid. 
Colorless  sirup. 

[a]«(approx.)  =    -  3.3°  (i 

Fischer:  Ann.  Chetn.  (Uebig),  370,  64. 

Fischer,  Passmore  :  Ber.  d.  chem.  Ges.,  33,  222*. 

Smith  :  Ann.  Chem.  (Liehig),  373,  183. 

Fischer  :  Ibid.,  288,  155- 

Fischer  :  Ibid..  270,  64. 

Fiacher,  Passmore:  Ber.  d.  chem.  Ges.,  33,  2234. 


OXYKETONES  589 

GALAOCTOSE,  C8H16O,  +  H2O.     From  galaoctonic  acid  lac- 
tone.     Thin  plates;  melting-point,  109°  to  m°. 
[a]  „  ;     -  40°  ' 

</-MANNONONOSE,    C9HleO,,.     From    </-mannonononic    acid. 
Crystals  ;  melting-point  about  130°. 


17.  Oxyketones.    Ketoses 

^-FRUCTOSE,  levulose,  fruit-sugar,  CH2OH.(CH.OH)3.CO. 
CH.,OH  =  C6H,,O6.  This  body  shows  left  rotation  in  aqueous 
solution,  which,  as  first  shown  by  Dubrunfaut,3  decreases 
rapidly  with  elevation  of  temperature.  Besides  this,  the  freshly 
dissolved  fructose  shows  multirotation  (§72).  The  numerical 
data  given  below  hold  for  the  constant  end  rotation. 

On  the  production  of  pure  levulose  from  inulin,  see  Wohl.* 
Earlier  investigations  by  Herzfeld,5  Winter,6  Herzfeld   and 
Winter7  gave  specific  rotations  which,   for  example,  forp  = 
20°    and    t  =  20°,     varied    between     [ac]D=    -70.59°    and 
-71-47°. 

The  following  observers  found  a  much  higher  value  : 
i.   Honig  and  Jesser.*     They  give  the  formulas  : 

a.  For  the  influence  of  temperature  : 

For/>=    9,       for]^=   —  103.92 -[-0.671 /,     for  t=  13°  1040° 
"  p  =  23.5,         "  =  —  107.65+0.692  t,      "  /=  9°  to  45°  : 

b.  For  the  effect  of  the  percentage  amount  of  water  q  in  the 
solution, 

[a]™  =    -  113.96  -r  0.258  q,     for  q  ~  60  to  95  per  cent.. 

from  which  follows  : 

For  loo  —  q=p=  5  10  20  30  40 

[a]-  -.=   -89.42     -90.72     -93.30     -95.88     -98.47° 

According  to  Honig  and  Jesser,  the  lower  values  of  Herz- 
feld depend  on  this,  that  in  the  conversion  of  inulin  into  sugar 

Fischer:  Ann.  Chem.  (Liebig),  388,  150. 

Fischer,  Passmore. 

Compt.  rend.,  43,  901. 

Ber.  d.  chem.  Ges.,  33,  2107. 

Ann.  Chem.  (lyiebig),  344,  287. 

Ibid.,  344,  300. 
"  Ber.  d.  chem.  Ges.,  19,  393. 
»  Ztschr.  fiir  Riibenzucker-Ind.,  (1888),  p.  1028. 


590 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


dextrines  are  always  formed  which,  by  the  method  of  puri- 
fication with  ether-alcohol  employed  by  the  latter,  cannot  be 
completely  removed. 

2.  Jungfleisch  and  Grimbert1  combine  the  following  deter- 
minations, made  for  different  concentrations  and  temperatures  : 


•  c  =  9-75- 

c  =  48.75- 

/  =  17°. 

/. 

WD. 

[<k 

c. 

["]/>. 

7° 

~  97.31 

QI   ^5 

o° 

,  TOC  76 

9nc  .  . 

QI    £1 

T  7 

lU^./U 

—  102.20 
Q7  62 

•/o  *  • 

y^-oo 
-  92.72 

y^-oo 
-  89.90 

/ 

16 

Ayo 

28  

y/.u^ 

-    90.39 

82   r-i 

oV-u 

yj-ou 
-  97.07 

02-53 

under  the  general  formula  : 

[a\lD  =  -  [101.38  —  0.56  /  -  0.108  (c  —  10)]. 
Ost'2  investigated   fifteen  solutions,   the  strength  of  which 
varied  between  i  and  30  per  cent,  of  levulose,  at  20°,  and  cal- 
culated this  formula  : 

M/?=   -  (91-9°  +  o.iu/0 

4.  Parcus  and  Tollens:i  found 

for/>  =  10,     /  —  20°,     [or]/,        —  92  to  92.5° 

5.  Wohl  found4 

for p  -^  10.17  or  c  =  10.57,     /       20°,     [a]/,        —91.8° 

According  to  the  above  five  observers,  the  specific  rotation 
of  a  10  per  cent,  solution  at  the  temperature  of  observation 
varies  between  [«]/>-  -  90.2°  and  93°. 

In  alcoholic  solution,  levulose  has  about  two-thirds  the 
rotation  shown  in  water. 

With  reference  to  the  multirotation,  or  decrease  in  the  rota- 
tion of  freshly  prepared  solutions,  we  have  the  following  ob- 
servations : 

i .   Parcus  and  Tollens  :  ' 

1  Corapt.  rend.,  107,  390. 
-  Her.  d.  chem.  Ges.,  34,  1636. 
1  Ann.  Chem.  (Uebig),  257,  160. 
4  Her.  d.  chem.  Ges.,  33,  2090. 
'•  Ann.  Chem.  (Liebig).  357,      6. 


INVERT   SUGAR  591 

c-     10,     /       20°,     First  rotation  after  6  mi n.  [a]/)        -104.0° 
End  rotation     "25    "         "          —92.3 
and  i  hour [«]/>       —92.1 

2.  Schulze  and  Tollens  :' 

c  =  10,     /  =  20°,      First  rotation  after  15  min.  [a]/)        —  92.3° 
End  rotation       "     20  hours     "          —90.9 

Iii  o.  i  per  cent,  ammonia  the  constant  end  rotation  is  reached 
in  five  minutes. 

3.  Jungfleisch  and  Grimbert2  give,   among  others,   the  fol- 
lowing observations  : 

c  =  1.779,    t  =  »'  c  =  9.75,    t  =  7°. 


After  10  min.  [a]o=   -106.02°  After    35  min.  [or]/>=  —97.33° 

"     20     "  "     =  —    99.32  "      55     "         "     =  —  96.11 

45     "  -    93-83  75                           -95-11 

"     90     "  -    92.00  105                           -94-77 

If  the  levulose  solution  in  water  is  heated,  a  further  gradual 
reduction  takes  place  according  to  Jungfleisch  and  Grimbert, 
and  to  avoid  this,  the  temperature  should  not  go  above  40°. 
But  Ost3  did  not  observe  this  decrease. 

According  to  their  strength,  acids  affect  the  specific  rotation 
of  levulose  in  different  ways  (Dubrunfaut,  Jungfleisch  and 
Grimbert,  Ost). 

Levulose  anilide  is  characterized  by  a  very  high  rotation. 
Sorokin4  found : 

In   ethyl   alcohol  p  =  0.712 [a~\D  =  —215.7° 

p  =  2.016 "  -185.5 

In  methyl  alcohol  p  —  1.436 "  -181.5 

1 8.  Invert  Sugar 

The  rotating  pow?er  of  the  invert  sugar  solutions  obtained  by 
the  action  of  acids  on  cane-sugar  solutions  has  been  investi- 
gated mainly  by  Gubbe/'  Ost,B  Wohl,7  and  others.  AsGubbe, 
and  later  Ost  found,  the  inversion  is  most  conveniently  accom- 
plished by  heating  100  parts  of  cane-sugar  with  i  part  of  oxalic 

1  Ann.  Chem.  (lyiebig),  271,  53. 

'-'  Compt.  rend.,  107,  390. 

:i  Her.  d.  chem.  Ges.,  34,  1643. 

4  J.  prakt.  Chem.,  [2],  37,  195. 

•"'  Ber.  d.  chem.  Ges.,  18,  2207. 

(-  Ibid.,  34,  1640. 

7  Ibid.,  23,  20^7. 


592  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

acid,  in  aqueous  solution,  for  several  hours  to  50°  or  60°.  No 
modification  of  the  rotation  of  the  invert  sugar  takes  place 
here  as  is  the  case  on  heating  with  hydrochloric  or  sulphuric 
acid. 

The  rotation  of  this  sugar  mixture  is  subject  to  many 
changes,  and  the  following  conditions  have  especial  influence. 

a.  Concentration. — From  careful    experiments,    Gubbe   de- 
duces the  following  formulas,  based  on  a  temperature  of  20°  : 

(I)  [or]*°  =  -  19.447  —  0.06068 p  -\-  0.000221  p- 

(II)  —  23.305  —  0.01649  q  -f-  0.000221  g*, 

holding  for/>  =  9  to  68,  or  q  =  32  to  91  ; 

(III)  [«]£=  -  19-657   -  0.0361  c, 

holding  for  c  up  to  35. 

Ost  gives  the  expression 

[a]£=    -  19-82  —  0.04 />, 
holding  for/>  =  2  to  30. 

b.  Temperature. — This  formula  was  given  by  Tuchschmidt,1 
for  c  —  17.21  and  /  =  5  to  35, 

{*}'„=  -  27.9 -f  0.32 /. 

Lippmann  found  nearly  the  same  in  a  series  of  experiments 
extending  to  /  =  8oV 

More  accurate  formulas  deduced  by  Gubbe  from  his  experi- 
ments are  these  : 
(IV)  For* ^=  o°  to  30°:  [or]',,  =  [<r]£  +  0.3041  (/  -  20)  +  0.00165  (/      20)-' 

(V)       "    t=-20°  "  100°:       "     a  "      +  0.3246(^  —  20)  —0.00021  (/  — 20)2 

If  we  calculate  the  values  for  different  percentage  strengths 
and  temperatures  of  invert  sugar  solutions  according  to  Gubbe' s 
formulas,  I  and  IV,  we  obtain  this  table : 


<-5- 

c  =  10. 

c  =  15. 

C  =  20.              C  =  25. 

c  —  3* 

,\  for 

'  —  5° 

-24.03 

-  24.21 

-  24.39 

-   24.58 

-  24-75 

-  24-93 

10 

-  22.72 

22.90 

-  23.08 

-   23.26 

-  23.44 

-  23.62 

I-3I 

15 

21.32 

21.50 

-21.68 

-21.86 

22.04 

—  22.22 

1.40 

20 

-  19.84 

-  2O.O2 

20.20 

20.38 

-  20.56 

-  20.74 

1.48 

25 

18.28 

18.46 

18.64 

-  18.82 

-  19.00 

-  I9.I8 

1.56 

T    Ar 

30 

16.63 

-  16.81 

-16.99 

-  I7.I7 

-  17-35 

17-53 

1.05 

0.18  0.18  0.18          0.18  0.18 

c  —  5J 

1  J.  prakt.  Chem..  [a],  a,  235. 

2  Ztachr.  fur  Riibenzuckcr-Ind.,  4,  303. 


INVERT   SUGAR  593 

As  the  rotation  of  invert  sugar  solutions  decreases  with  tem- 
perature elevation,  it  must  follow  that  it  becomes  o  at  some 
definite  temperature  and  changes  to  right  rotation  at  a  still 
higher  heat.  This  temperature  of  inactivity  is  87.2°  accord- 
ing to  Tuchschmidt,  and  87.8°  according  to  Lippmann. 

For  solutions  inverted  with  oxalic  acid,  Gubbe  found  these 
temperatures  : 

79-39°  (c  =  i°).         So^S0  (c  —  20),        81.47°  (c  =  30) 

The  decrease  and  final  change  in  direction  of  rotation  is  ex- 
plained by  the  fact  that  the  rotating  power  of  levulose  dimin- 
ishes rapidly  with  increasing  temperature,  while  that  of  dex- 
trose is  but  slightly  changed. 

c.  Presence  of  Acids. — That  the  specific  rotation  of  invert 
sugar  solutions  made  from  cane-sugar  suffers  a  change  by 
reason  of  different  amounts  of  acids  employed  was  shown  first 
by  Dubrunfaut,1   and  later   by    Gubbe.2      According   to   the 
experiments  of  the  latter,   hydrochloric  and  sulphuric  acids 
produce  an  increase  in  the  specific  rotation,  which,   for  solu- 
tions containing  10  parts  of  invert  sugar  in   100  parts  of  water 
and    s    parts    of  acid,  may  be  expressed    by    the  following 
formulas  : 

Sulphuric  acid...    [a]»°=   -  (19.983  -f  0.1698  s)  holding  for  s  =  o.  i  to  5 
Hydrochloric  acid       "    :      —(19.9954-0.32625)  '   5  =  0.1103 

If,  however,  cane-sugar  is  inverted  with  different  amounts 
of  oxalic  acid  (o.  i  to  4.3  parts  for  10  parts  of  invert  sugar  and 
100  parts  of  water),  the  specific  rotation  remains  constant. 

If  an  invert  sugar  solution  is  warmed  with  hydrochloric  acid 
and  then  diluted,  the  liquid  does  not  assume  the  proper  end 
rotation  corresponding  to  the  dilution  until  after  about  twenty- 
four  hours. :' 

d.  Temperature  of  Inversion. — Invert  sugar  solutions   made 
by  action  of  mineral  acids  on  cane-sugar  solutions,  with  appli- 
cation of  heat,  suffer  a  decrease  in  the  rotation  if  the  heating  is 
increased  or  long-continued. 

There  are  no  accurate  experiments  on  this,  but  only  occa- 

1  Compt.  rend.,  23,  38. 

-  Ber.  d.  chem.  Ges.,  18,  2210. 

3  Gubbe  :  Ibid.,  18,  2211  ;  Wohl  :  Ibid..  23,  2087. 

38 


594  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

sional  statements.  According  to  Herzfeld,1  if  a  solution  con- 
taining 13.024  grams  of  cane-sugar  in  50  cc.  of  water  is  warmed 
with  5  cc.  of  38  per  cent,  hydrochloric  acid  to  69°,  the  inver- 
sion is  complete  in  seven  minutes,  and  in  fifteen  minutes,  a 
decrease  in  the  rotation  has  already  begun.  Under  the  same 
conditions,  but  employing  75  cc.  of  water,  the  maximum  rota- 
tion is  again  reached  in  seven  minutes  and  the  decrease 
begins  in  twenty  minutes.  Wohl'  also  found  that  when 
invert  sugar  solutions  are  warmed  with  hydrochloric  acid 
for  some  time,  the  left  rotation  as  well  as  the  copper  oxide  re- 
ducing-power  decreases  more  and  more,  because  dextrine-like 
products  are  formed  from  the  levulose. 

In  general,  the  velocity  of  inversion  increases  rapidly  with 
the  temperature,  and  for  all  acids.  In  addition,  when  strong 
acids  are  used,  it  is  increased  by  the  presence  of  neutral  salts  of 
the  same  acids,  which  action,  however,  diminishes  with  ele- 
vation of  temperature/1 

e.  Formation  of  Dehydration  Products. — If  acid-free  invert 
sugar  solutions  are  evaporated  in  vacuo  to  a  sirup,  dehydration 
compounds  (right- rotating  levulosan)  are  formed,  and  on  re- 
solution a  much  weaker  left  rotation,  or  even  a  right  rotation, 
is  found.  On  standing  several  hours  in  the  cold  or  after  heat- 
ing a  short  time  to  67°  to  70°  with  addition  of  hydrochloric 
acid,  the  normal  rotation  returns.' 

b.  Behavior  of  Inactive  Bodies. — Alcohol  greatly  decreases 
the  left  rotation  of  invert  sugar,  and  on  warming,  right  rota- 
tion may  appear/'  According  to  Landolt,"  a  solution  of  20 
grams  of  invert  sugar  in  15  cc.  of  water  and  diluted  with  abso- 
lute alcohol  to  loo  cc.  is  inactive  at  38°,  and  rotates  above 
this  temperature  to  the  right,  and  below  it  to  the  left.  Accord- 
ing to  Horsin-Deon,  anhydrous  invert  sugar  dissolved  in  abso- 
lute alcohol  shows  no  rotation,  but  becomes  left-rotating  on 
addition  of  water. 

Ztschr.  fiir  Riibenzucker-Ind.  (1888),  p.  707. 
Her.  d.  chem.  Ges.,  33,  zog6. 
Spohr  :  J.  prakt.  Chem.,  [2],  3a,  32. 

Degener :  /tschr.    fiir  Riibenzucker-Ind.  (1886),  p.    344;    Herzfeld  :  Ibid.  (1887), 
P-  908. 

Jodin  :  Compt.  rend..  58,  613. 
Her.  d.  chem.  Ce«.,  13,  2335. 


INVERT   SUGAR 


595 


Lime  produces  a  decrease  in  the  left  rotation.1 

Basic  lead  acetate  added  in  increasing  amounts  to   an  invert 

sugar  solution  decreases  the  left  rotation,   and  converts  it  into 

increasing  right  rotation.' 

On  employing  a  basic  lead  acetate  solution  of  1.222  sp.  gr., 

Bittmamv  found  these  deviations  in  the  Ventzke  saccharimeter. 


Invert  sugar             w»t*r 
solution.                 ^cacten 

Basic  lead 
acetate, 
cc. 

Ventzke 
degrees. 

50                          50 

-2.3° 

50 

40 

10 

—  i.o 

50 

30 

20 

-f  3-7 

50 

10 

40 

+  7-5 

10 

40 

—  2.2° 

10 

3° 

10 

-f   1-5 

10 

40 

+  6.4 

5 

5 

40 

+  7-6 

Invert  sugar 
solution, 
cc. 

Alcohol, 
cc. 

Basic  lead 
acetate, 
cc. 

Ventzke 
degrees. 

10 

40 

-0.4° 

IO 

3° 

10       -j-  4.0 

10 

20 

20 

-6.9 

5 

45 

-0.4° 

5 

35 

10 

+  8.6 

Composition  of  Invert  Sugar. — For  a  long  time  it  has  been 
assumed  that  invert  sugar  is  a  mixture  of  equal  parts  of  dex- 
trose and  levulose,  but  it  is  only  recently  that  the  correctness 
of  this  assumption  has  been  shown  by  Honig*  and  Jesser,  which 
they  did  by  proving  that  the  arithmetical  mean  of  the  specific 
rotations  of  the  two  components  coincides  with  the  specific 
rotation  of  invert-sugar.  This  proof  was  never  successful 
before,  because  sufficient  knowledge  of  the  numerical  data 

1  Jodin:  Loc.  cit. 

'-'  C.  Haughton  Gill  :  J.  Chem.  Soc.,  24,  91. 
a  Ztschr.  fur  Riibenzucker-Ind.,  (1880),  p.  876. 
*  Ibid..  (1888),  p.  1037. 


596 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


in  question  was  lacking.     These  data  are  given  by  the  follow- 
ing formulas  : 

Dextrose M#  =  +  52-5°    +0.0188   />  +  0.0005 17  P*  l 

Levulose "          —88.13    —0.2583  p 

Invert  sugar "  -  19.447  —  0.06068  p  +  0.000221  p*  'A 

If  now  the  specific  rotations  of  these  sugars  for  different 
strengths,  p,  be  calculated,  we  have  from  the  above  formulas  : 


p. 

Dextrose. 

I^evulose. 

Arithmetical 
mean. 

Invert-sugar. 

Difference. 

20 

+  53-08 

-  93-30 

—  20.11 

-  20.57 

+  0.46 

25 

+  53-29 

-94-59 

—  20.65 

-  20.83 

+  0.18 

30 

+  53-53 

-95-88 

-  21.  18 

—  21.07 

—  O.I  I 

35 

+  53-79 

-97.17 

-  21.69 

-  21.30 

-0.39 

The  same  calculation  has  been  carried  out  by  Ost.4 
The  agreement  with  observation  confirms  the  above  assump- 
tion  fully   and  an  earlier  suggestion  of  Winter5  that  invert 
sugar  may  be  made  up  of  4  parts  of  levulose  and  3  parts  of 
dextrose  is  evidently  in  error. 

19.  Disaccharides  (Saccharoses,  Bioses) 
CANE-SUGAR,  C,2H22OU.     Right-rotating. 
For  the  relation  of  the  specific   rotation  of  the  sugar  in 
aqueous  solution  to 

1.  The  percentage  amount/  of  sugar, 

2.  The  percentage  amount  q  of  water, 

3.  The  concentration  c,   or  grams  of  sugar  in   100  cc.,  the 
following  formulas  have  been  given,  based  on  accurate  obser- 
vations : 

I.  By  Tollens.6     Calculated  from  19  solutions. 
i.  Specific  gravity  of  the  solutions  at  17.5°,  referred  to  water 
at  4°.     Rotation  at  20°  : 

a    \P=   4  to  18,  \JOL\D=  66.810  —  0.015553 p  —  0.0452462 p1 7 
"  \q  =  82  to  96,        "    =  64.730  +  0.026045  q  •--  0.0452462  q1 
b     (p  —  18  to  69,       "    =66.386  +  0.015035^  —  0.033986   p1 
\q  —  31  to  82,       "    —  63.904  +  0.064686  q  —  0.033986  q2 

Tollens. 

Honig  and  Jesser. 

Gubbe. 

Her.  d.  chem.  Ges.,  34,  1640. 

Ann.  Chem.  (I«iebig),  344,  295  and  329. 
«  Ber.  d.  chem.  Ges.,  10,  1403. 
1  0.0452462  ^  0.000052462,  etc. 


DISACCHARIDES  597 

Later,  Tollens1  found  that  the  formulas  b  satisfy  dilute  solu- 
tions also,  down  to  p  =  i  even. 

2.  Specific  gravity  of  solutions  at  17.5°  referred  to  water  at 
17.5°.  Rotations  at  20°. 

From  the  same  experiments  as  under  i  there  follows  for  p. 

a',  p  —    4  to  18,     [a]/>  ==  66.727  —  0.015534 /»  —  0.0452396 p 
b '.p=  1 8  to  69,        "       -  66.303  —  0.015016 p  —  0.033981   /* 

By  another  method  of  calculation,  Thomsen2  obtained  from 
the  observations  of  Tollens  these  expressions  in  place  of  those 
given  under  b  above, 

v,  J>  =  18  to  69,     \a\n  =  66.577  -f  0.007466  /  —  0.0331339^ 
t?  =  31  to  82»         "    —  64.190  -f  0.055212  q  —  0.0.331339  #2, 
which  agree  well  with  the  Schmitz  formulas  given  below  under 
II.,  i. 

II.  Schmitz3  gives  these  formulas  deduced  from  eight  solu- 
tions (see  §54,  p.  195). 

1.  Specific  gravity  of  the  solutions  at  20°   referred  to  water 
at  4°.     Rotations  at  20°. 

p  =   5  to  65,     \ci\D  =  66.510  -f  0.004508 p  —  0.0328052 p 
<1       35  to  95,         "         64.156  —  0.051596  q  —  0.0328052  q* 

2.  For    the    concentration    at    20°     Schmitz    gives    these 
formulas : 

c  10  to  86,  [<*]/>  66.453  —  0.001236  c  —  0.0311704  & 
c  2.5  to  28,  "  =  66.639  —  0.020820  c  -^  0.0334603  c1 
c  2.5  to  28,  k'  66.541  —  0.008415  <: 

L,andolt4  has  calculated  these  approximate  expressions  from 
the  observations  of  Tollens  amd  Schmitz,  showing  the  relation 
of  the  specific  rotation  and  concentration  of  solutions  : 
c       4.5  to  27.7,     [a]£     •-  66.67  —  0.0095  c  (true  cc.) 
c       4.5  to  27.7,     [or]*?-5   --  66.82  —  0.0096  c  (Mohr's  cc.) 

III.  The  latest  experiments  have  been  carried  out  by  Nasini 
and  Yillavecchia.5     These  formulas  follow  from  twelve  series 
of  observations  with  different  sugars  : 

P         3  ^  65,     [a]=(;  66.438  -f  0.01031 2  p-  0.0335449/2 
q       35  to  97,  "    63.924  +  0.060586  q  —  0.0335449  q' 

1  Ber.  d.  chem.  Ges.,  17,  1751. 

-    Ibid.,  14,    1652. 

3  Ibid.,  10,  1414. 

4  Ibid.,  ai,  196. 

'•>  Public,  de  lab  chim.  centr.  delle  gabelle,  Roma  (1891),  p.' 47. 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

If  we  combine  now  the  results  which  the  different  formulas 
give  for  a  number  of  different  percentage  amounts  of  sugar,  we 
find  these  variations : 


Formula.                           /  = 

IO. 

20. 

30- 

40. 

50. 

\tl 

66  65 

66  48 

66  70 

66  10 

Ac  QO 

TA 

Toll  en  ^ 

66  «;o 

66  57 

66  48 

66  7=; 

66  14 

TA// 

66  62 

66  60 

66  «;2 

66  77 

66   T7 

Scliinit/  

66  <;•; 

66  AQ 

66  10 

00.31 

66  24 

66  oi 

III. 

Nasini  and  Villavecchia 

""Oo 
66.51 

66.50 

WW.£«f 

66.43 

66.28 

""•  ^o 

66.07 

It  is  seen  that  the  values  given  by  the  last  two  formulas  fur- 
nish the  closest  agreement. 

With  reference  to  the  specific  rotation  of  cane-sugar  in  very 
dilute  solutions,  see  the  observations  given  already  in  §55. 

For  the  rotation  of  different  rays  of  light  by  cane-sugar,  see 
''Rotation  Dispersion,"  §45. 

Influence  of  temperature.  This  was  formerly  held  by  Mit- 
scherlich,1  Hesse,2  also  Tuchschmidt1  to  be  extremely  small. 
Andrews*  was  the  first  to  show  that  the  specific  rotation  of 
sugar  decreases  with  elevation  of  temperature  and  to  the  extent 
of  0.0114  for  i°  C.  According  to  new  experiments  which 
Schonrock5  has  carried  out,  using  ten  sugar  solutions,  the  tem- 
perature coefficient  lies  between  0.0132  and  0.0151.  This 
formula  may  be  used  to  calculate  the  specific  rotation  of  solu- 
tions of  about  24  per  cent,  strength,  for  a  temperature  differ- 
ent from  20°,  between  the  limits,  12°  and  25°. 

[«]'/,  =  MS  -  0-0144  (t  -  20) 

Recently  Wiley*5  has  reinvestigated  the  subject  with  extreme 
care  and  has  found  a  value  lower  than  those  given  above. 
The  coefficient  as  given  by  him  is  0.00994  as  tne  mean  change 
in  the  specific  rotation  for  each  degree  centigrade. 

In  the  paper  by  Andrews,  the  value  is  given  in  one  place  as 

'  Ber.  d.  Bcrl.  Akad.,  (1842),  p.  150. 

*  Ann  Chem.  (t,iehig),  176,  97. 
»  J.  prakt.  Chem.,  [2],  a,  244. 

«  Technology  Quarterly,  May  (1889),  p.  367 :  Chem.  Centrhl.,  (1890),  I,  p.  20. 

*  Ber.  der.  phys.-techn.  Keichsanstalt  von  1896  ;  /tschr.  fiir  lustrum.,  17,   iho. 

*  J.  Am.  Chem.  Soc.,  at,  568  (1899). 


DISACCHARIDEvS  599 

o.oooi  14.  But  the  context  shows  that  this  is  a  typographical 
error  for  0.0114. 

On  the  specific  rotation  of  cane-sugar  in  mixtures  of  water 
with  acetone,  methyl  alcohol,  and  ethyl  alcohol,  see  §59. 
According  to  Seyffart,1  sugar  retains  the  same  specific  rotation 
when  dissolved  to  the  extent  of  5  to  40  grams  in  100  cc.  of 
alcohol  of  9°  to  go0.2 

The  changes  shown  in  the  specific  rotation  of  cane-sugar  in 
presence  of  alkalies  and  salts  have  been  explained  already  in 
§70. 

MILK-SUGAR.  Lactose,  Lactobiose.  Anhydrous,  C^H^C^ ; 
hydrated,  CKHMO10  +  H,O. 

As  already  shown  in  the  chapter  on  multirotation,  §72,  this 
sugar  is  found  in  three  modifications,  of  which  a  and  y  in 
aqueous  solution  pass  slowly  into  ft  at  the  ordinary  temper- 
ature, but  rapidly  on  warming.  The  tr-form  exhibits  greater 
rotation  (birotation),  and  the  y-form  less  rotation  (half 
rotation)  (see  §71). 

Anhydride.  Hydrate. 

1.  or-Modif.  ordinary  milk-sugar [a]D  =  88°  +  84° 

2.  /3-      "       stable  form "  ^   +55-3°  +52-53 

3.  7-      "       second  labile  form "  '-7-36.2  34-4 

Ordinary  Milk- Sugar. — The  beginning  rotation  of  this  can- 
not be  accurately  determined,  because  of  rapid  change  into 
the  yS-form,  and  is  always  found  too  small.  Schmoger3  found 
[a]D=  -(-84°  (for  the  hydrate),  and  Parcus  and  Tollens4 
+  83°. 

The  following  series  of  experiments  by  Parcus  and  Tollens 
gives  a  picture  of  the  change  into  the  stable  /?-form  which  fol- 
lows in  milk-sugar  solutions  at  the  temperature  of  20°,  the 
time  being  counted  from  the  moment  of  adding  water  to  the 
finely  powdered  substance  : 

i  Ztschr..  fiir  Riibenzucker-Ind.  (1879),  III,  p.  130. 

"  Tralles. 

•;  Ber.  d.  cheni.  Ges.,  13,  1918. 

4  Ann.Chem.  (I,iebig),  257,  170. 


6oo 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


/  =  20°       C  =  4.841. 

t=  20° 

c  =  7.064. 

Time. 

[«k 

Time. 

[«]/>. 

8  min. 

82.91° 

10     "                  82.56 

15     " 

Si.ti 

20      " 

79.69 

25  min. 

78.86° 

30       " 

76.48 

30     " 

77.14 

45     " 

73.26 

40    " 

74.94 

i  hour 

70.04 

I'/s  hours 

65.76               il  ,  hours 

68.57 

2 

62.17 

2 

61.70 

21/,       " 

58.97 

3        " 

57-54 

iV      " 

3  hi 

55.84 

41/.     " 

54.32 

5        V 

53-60               5         " 

54.25 

6 

53-43 

7 

53-25 

7 

52.90 

24        " 

52-53 

24 

52.53 

As  opposed  to  the  earlier  statements  of  Hesse,1  Schmoger 

shows  that  the  rotating  power  of  milk-sugar  for  c  =  2.372  to 

41.536  is  independent  of   the  concentration.     He   finds  from 

the  mean  of  70  polarizations  the  constant  rotation  at  20°,  for 

C12H.22On  4-  H.20 [a]/,     -  +  52.53° 

Exactly  the  same  value  is  found  by  Deniges  and  Bonvans.3 
However,  according  to  experiments  of  Schmoger,  the  temper- 
ature influences  the  rotating  power  which  sinks  as  the  solution 
becomes  warm.  This  effect  is  greater  at  20°  than  at  higher 
temperatures.  In  the  neighborhood  of  /  =  20°,  [#]  /,  changes 
about  0.070°  for  one  degree  of  temperature  as  shown  by  the 
following  table  : 


at 


p. 

*?. 

9°. 

10°. 

MO. 

20". 

21". 

32". 

33, 

35«>- 

37°. 

-8.307 

1.0301 

52.76°  52.36° 

51.60° 

15.950 
16.664 

1.  0661 

1.064253.46° 

53-50° 

52.56 

52.36° 

.        I 

5L48° 

51.40° 

24.785 

1.0992 

i52.56 

51-59° 

'  Ann.  Chem.  (Uebig),  176,  98. 

*  Ber.  d.  chem.  Ges.,  13,  1922. 

3  J.  pharm.  chim.,  [5],  17,  363:  Chem.  Centrhl.  (1888),  p.  6o;v 


DISACCHARIDES  6oi 

If  the  rotation,  at,  of  a  milk-sugar  solution  has  been  found 
at  the  temperature  /,  it  may  be  reduced  to  the  value  at  20°  by 
this  formula  : 

1020  —  / 


By  the  action  of  dilute  acids,  milk-sugar  is  inverted  and 
glucose  and  ga  lactose  are  formed,  which  may  be  shown  by 
polarization.  If,  for  example,  c  =  11.9734  and  /  =  20°,  there 
may  be  calculated  from  the  rotation  of  glucose,  [a]  D  =  52.84°, 
and  of  galactose,  [«]/>  =  79-73°,  that  of  the  inverted  milk- 

sugar  as  ^1_±_79^73  =  6629°       Rindell1    found     [ci]D  = 

67.57  Ior  this  rotation,  and  showed  that  it  is  influenced  by  the 
temperature  according  to  the  following  formula  : 

[a]D  =  70.608°    -  o.  152  /. 
Alkalies  diminish  the  rotating  power  of  milk-sugar  : 

i  mol.  cryst.  milk-sugar  -f  I  mol.  Na.,O  : 
t  =  20°t     c  =  z,     [»atonce  .........   -    -'-  45-5°V 

/       20°,     c  =  3,         "     after  24  hours-  ..      -  -f-  12.57  j 

Half  -Rotating  Milk-Sugar  (y-form).  This  is  produced  as 
already  explained  in  §72.  The  beginning  rotation  is  found 
too  large  because  of  the  rapid  conversion  into  the  more  strongly 
rotating  /?-form.  Schmoger3  obtained  for 

c  =  7.07,     [or]y,  =  4-  34-4  :    c  =  7-72,     [a]  i,  =  -f  36.2°. 

The  conversion  of  a-  and  also  ^-milk-sugar  into  the  constant 
y^-form  is  hastened  by  addition  of  o.i  per  cent,  ammonia/ 

Milk-Sugar  Octoacetate,  C1;!HUOU(C2H3O)8.  This  is  left-rota- 
ting and  exhibits  neither  birotation  nor  half-rotation. 

Chloroform  ..............  p       about  10,     \_cc]D  =    —  3.5°  '' 

MALTOSE,  Maltobiose,  Malt  Sugar,  Ptyalose,C12H28On+HaO. 
Crystallizes  in  fine  needles  with  i  molecule  of  water  of  crystal- 
lization, which  is  lost  at  100°. 

The  earlier  statements  on  the  rotation  of  maltose  gave  values 
between  [<*]/>  =  -f  139°  and  150°.  The  first  reliable  obser- 

1  Ztschr.  fiir  Riibenzucker-Ind.,  4,  163. 

-  Hesse  :  Ann.  Chem.  (I^iebig),  176,  101. 

•"•  Her.  d.  chem.  Ges.,  13,  1918. 

4  Schulze  and  Tollens  :  Ann.  Chem.  (I«iebig),  371,  49. 

;>  Schmoger  :  Ber.  d.  chem.  Ges.,  35,  1452. 


602 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


vations  were  made  by   Meissl.1     He  found  that  maltose,   like 
lactose,  shows  half -rotation. 


c. 

15.61 

18.94 
19.4 

[>]/,  aft 
7  hours. 

er 
8  hours. 

5  min. 

i  hour. 

4  hours. 

24  hours. 

4  days. 

138.3 
138.3 
138.2 

122.6 
122.5 
122.0 

126.2 
127.4 
127.0 

132.0 

!33.o 

135.0 

137-0 
J37-6 
138.0 

137-2 
138.2 

138.3 

133.3 
138.2 

138.3 

Parcus  and  Tollens2  also  investigated  the  half-rotation  in  two 
different  solutions,  and  found  : 


Preparation 


Preparation  2. 


/  =  20°. 

c  =  10.040  for  hydrate. 
c  =   9.537  for  anhydr. 

t  =  20". 

r  =  9.679  for  hydrate. 
c  =  9.195  for  anhydr. 

/  =  20". 

c  =  10.320  for  hydrate. 
c  =    9.804  for  anhydr. 

Time. 

[a]/>  for 

anhydride. 

1 
Time. 

|»for 
anhydride. 

1    ' 

Time.              M'j  for 
anhydride. 

8  min. 

119.36° 

12  min. 

120.97° 

6 

min.         118.75° 

10     "            120.27              14     " 

121.16               8 

119.46 

15     "             121.01               16     " 

122.29             10 

120.34 

20      "                 121.72                    20       " 

123.23                    12 

120.69 

30   "        123.35         25   " 

124-55                    15 

"               121.22 

45     ''             125.17              30     " 

125.68                   20 

122.28 

i  hour         128.07              40     " 

127.56                   30 

124.04 

i  l  .,  hours 

I30.97                 50      ' 

129.44                   50 

127.04 

2           " 

'32-97 

I  hour 

130.57                      I 

hour        128.81 

2',        « 

134.05                il/4  hours 

132.63            i    i»/2  hours   131.45 

3 

134.96 

!*/« 

I34JI                       2 

133.22 

5        " 

136.52 

2 

135-27                3 

I35.I6 

7 

136.72 

2'/4       M 

T35-65            1    4 

136.40 

9 

136.96  const 

33/*     " 

136.40 

6 

"        136.  75  const. 

5 

136.87001151. 

I 

The  constant  end  rotation,    as  with    milk-sugar,   is  more 
quickly  reached  by  heating  the  solution  or  by  adding  ammo- 


nia to  it.3 

'  J.  prakt.  Chem.,  ai,  284  and  35,  n.j. 

-  Ann.  Chem.  (Uebig),  357,  172. 

•  Schulzeand  Tollens  :    Ibid.,  27  I,  53. 


DISACCHARIDES 


60.^ 


The  constant  end  rotation  is  dependent  on  the  temperature 
and  concentration,  as  shown  by  observations  of  Meissl,1  which 
may  be  expressed  by  this  formula  : 

[a-]/,  =  140.375  —  0.01837  P  —  °.°95  / 

From  this  we  have  the  following  agreement  between  obser- 
vation and  calculation  : 


p. 
4.95 

d 

at  17.5". 

15"- 

17.5". 

25°. 

35"- 

Found. 

Calc. 

Found. 

Calc. 

Found. 

Calc. 

Found. 

Calc. 

.01961 

138.67 

138.86 

138.46 

138.62 

137.97 

137-91*  137.08 

136.96 

9.70 

.03928 

138.79 

138.77 

138.54 

138.53 

137.84 

137.82 

136.95 

136.87 

18.65 

.0/777 

138.56 

138.61 

138.33 

138.37 

137-57 

137.66 

136.75 

136.71 

18.67 

.07779 

138.68  138.61 

138.40 

138.37  137.68 

137-66 

r36./9 

136.71 

19.68 

.08281 

138.70 

138.59 

138.30 

138.35  137-59 

I37.64 

136.66 

136.69 

19.91 

.08309 

138.50 

138.58 

138.39 

138.34  137-55 

I37-63 

136.61 

136.68 

33-86 

.14873 

138.35 

138.33 

138.12 

138.09  137.33 

137.38 

136.38 

136.43 

34.72 

.15361 

138.26138.31 

138.00 

138.07  137.29 

137.36 

136-37 

136.41 

34-95 

.15500 

138.34 

138.31 

138.11 

138.07  137.40 

137.36 

136.48 

136.41 

Herzfeld2  gives  : 
Water *  =  20°,    /    -  11.29,     aff  =  1.044°,     MZ>       4-  138.29° 

(From  Meissl' s  formula  there  is  calculated  :  138.27). 

Ost3  finds: 

Water  .    c  ---  2  to  21,     t  =  20°,     [cc]D  =  +  137.04° 

Brown,  Morris  and  Millar4  also  obtain  values  which  closely 
agree  with  those  of  Meissl. 

Octacetyl    Maltose,   C12HUOU(C,H3O)8.  Crystals  ;    melting- 
point,  150°  to  155°. 

Benzene £=1.9956,  \_O\D  =  8i.i8c 

Benzene p       2  "  =75.7 

Alcohol ^=2  "  =  60.0 

Benzene p       2  "  =76.54 

Chloroform /        2  "  =  61.01 

Alcohol p        r  "  ^60.02 

1  J.  prakt.  Chem.   [2],  35,  114. 

-  Ztschr.  fiir  Riibenzucker-Ind.,  (1895),  p.  236. 
;  Chem.  Ztg.,  19,  1727. 

4  J.  Chem.  Soc.,  71,  72. 

•  Herzfeld  :  Ann.  Chem.  (I^iebig),  jao,  218. 

6  Herzfeld  :  Ztschr.  fiir  Riibenxucker-Ind.,  (1895),  p.  235. 
'  Herzfeld  :  Ber.  d.  chem.  Ges..  28,  441. 


r 


604  CONSTANTS   OF   ROTATION   OF   ACTIVE    BODIES 

ISOMAI/TOSE  Gallisin,  C13H21OU.  This  is  formed  in  the  yeast 
fermentation  of  grape-sugar,1  or  in  the  treatment  of  this  sugar 
with  hydrochloric  acid." 

The  specific  rotation  in  aqueous  solution  increases  approxi- 
mately in  proportion  to  the  amount  of  solvent  employed  : 

Water /  .=  20°,     £--54.58,     OL  =  +  77-32 

£=27.29,         "--4-80.10 
c=  10.60,          "  =  -f-  82.76 

Lintner  and  Dull*  give  for  a  preparation  of  isomaltose  from 
starch,  but  which  probably  was  not  pure,  [or],,  ==  140°  in  10 
per  cent,  solution. 

TREHALOSE,  Mycose,  C,,H22OU  -f-  2H,O.  Rhombic  crystals  ; 
melting-point,  210°. 

Water c  —  8.4  to  14.8    /       15° 

[cr]y  =  -f-  199°  (.=  220°  for  anhydrous  subst.)5 
Water. . . .   c       10.03,         [«L  =  +  173-2°  6 

MELIBIOSE,  Raffinoboise,  C]2H22On.     Amorphous  powder. 

Water c       3.957,     /       17°,     I»         -126.7° 

Water <"       3-973,     f       !7,  "  127.9 

These  are  only  approximate  values,  as  we  have  no  guarantee 
of  the  purity  of  the  amorphous  sugar.7 

Water /   -=  17.5°,     [or]/,        137.32°  " 

Octacetyl  Melibiose,  C1VHUOU  ( C2H3O ) K. 
-:t  Alcohol--    '.chloroform c^-  1.6516,     /       18°,     [a]/,       +94.209 

CYCLAMOSE,  C12H22On.  From  the  roots  of  Cyclamen  euro- 
pacum.  The  specific  rotation  is  not  affected  by  the  temper- 
ature, and  is 

[>]/>= -15- 15°. 

On  heating  with  dilute  hydrochloric  acid,  the  rotation  is  in- 
stantly changed  to  \oi\n  —  -  66.54,  but  under  the  influence 
of  the  heat,  soon  decreases.10 

1  Schmitt  and  Cobenzl :  Her.  d.  chem.  Ges.,  17,  1000. 

•  Fischer  :  Ibid.,  33,  3688. 

'•'•  Schmitt  and  Cobenzl  :  Ibid.,  17,  1007. 
4  Ztschr.  angew.  Chem.,  1892,  p.  263. 

•  Berthelot :  Ann.  chim.  phys.,  [3],  55,  276. 
Mitscherlich  :  J.  prakt.  Chem.,  [I],  73,  65. 

'  Scheiblerand  Mittelmeier :  Ber.  d.  chem.  Ges.,  a3,  1438. 

•  Bau  :  Chem.  Ztg.,  ai,  186. 

1  Scheibler  and  Mittelmeier. 
'"  Michaud  :  Chem.  News,  33,  232. 


TRISACCHARIDES   AND    POLYSACCHARIDES  605 

20.  Trisaccharides  and  Polysaccharides 

RAFFINOSE,  Melitose,  Melitriose,  Gossypose.  C18H32OU  -f 
5H2O.  Melting-point  118°  to  119°.  It  is  found  in  various 
vegetable  products. 

The  rotating  power  was  found  by  several  older  observers,  in 
pretty  close  agreement,  as 

[or],,  =:  +  104.5°,  for  f  =  20°, 
and  to  be  but  slightly  dependent  on  temperature. 

Tollens1  found  that  these  different  products,  investigated  by 
the  earlier  chemists,  melitose  from  eucalyptus  manna,-  raffinose 
from  molasses, :{  gossypose  from  cottonseed/  are  identical  and 
show  the  following  values  : 
I.  Raffinose  from  molasses  : 
Water />         9.817,     t  =  20°,     ^=1.03278,     [a]D  —  +  104.9° 

II.  Raffinose  from  cottonseed  : 
Water p.—  11.158,     /  =  20°,     ^*°— 1.03279,     [«]/?---—  104.39° 

III.  Raffinose  from  eucalyptus  manna  : 
Water p—    9.777,     t  —  20°,     d'°  =  1.03172,     [a]/)  =  —  104.44" 

Raffinose  is  found  also  in  the  sugar-beet. 

Water p  =  2.7616,     ^  =  18°,     \a\D  —  104.96°  •' 

Rischbiet  and  Tollens  give  : 6 

1.  Raffinose  from  molasses  : 

Water c  =  10,     [«]/>  =  -f  102.4  to  104.9° 

2.  Raffinose  from  cottonseed  : 

Water c  =  10,     [a[>  =  104.4° 

Creydt7  found : 

Water /  =  20°,     c  =  16.6 

Raffinose  from  molasses [a]z>  =  104.2° 

"      cotton-seed "      ^104.5 

In  the  inversion  of  raffinose,  two  stages  may  be  distinguished. 
When  its  solution  is  warmed  gently  with  weak  acid,  the  rota- 
tion sinks  to  about  one-half,  but  goes  no  further  ;  but,  on  the 

Ann.  Chem.   (I,iebig),  232,  169. 
Berthelot :  Ann.  chim.  phys.,  [3],  46,  66, 
I,oiseau  :  Compt.  rend.,  82,  1058. 
Bohm  :  J.  prakt.  Chem.,  [2],  30,  37. 
I,ippinann  :  Ber.  d.  chem.  Ges.,  18,  3089. 
Ann.  Chem.  (L,iebig),  232,  169. 
Inaug.  Diss.,  Erlangen,  1888. 


6o6  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

other  hand,  if  the  solution  is  warmed  a  long  time  with  some- 
what stronger  acid  the  rotation  is  decreased  to  one-fifth  the 
original  value. 

Thus,  a  raffinose  solution  with  c  =  10,  to  which  6  cc.  of 
sulphuric  acid  of  sp.  gr.  1.0591  had  been  added,  gave  : 

After  '  ,  hour's  heating  to  100°  ........    [«]/>       49.8°  at  20° 

"      i      "  "    80°  ........         "        49.1    at  20 

"     14  days'  standing  in  the  cold  .....         "    ~  53.6    at  20 

But  when  10  grams  of  raffinose  was  dissolved  with  5  cc.  of 
sulphuric  acid  of  sp.  gr.  1.156  and  water  to  make  100  cc.,  and 
was  then  heated  five  hours  to  100°,  it  showed  [ai]D  =  -\- 
20.07°  ' 

Scheibler  has  shown  that  the  specific  rotation  of  raffinose 
does  not  change  with  the  concentration  or  by  the  addition  of 
alcohol. 

Raffinose  from  beet-sugar  : 

Water  ............   c       10,     /  ^  17.5°,     [a]/,     =  +  103.74° 

"      ...........     £=15.     '    -  !7-5  ^+103.97 

Alcohol  (15  p.  c.)..  c—  ro,     /  :.=  17.5  =  -f  103.9 

Raffinose  from  cottonseed  : 

Water  ............   c  ---  5  /  —  17.5  [or]/?  =  -f  104.0 

"      ............   C=IO  1=17.5  =  +  103.9 

"      ............   c       15  /^i7-5  ^+103.95 

Undecylacetylmeletriose,  C1HH21O18(C2H3O)n.  Crystals  with 
melting-point  99°  to  101°. 

Alcohol  .........   c  :-  8.1988,     /        17°,     [a]/,      -  +  92.2°  3 


MELEZITOSE,  CI8HMO16  -f-  2H,O.     Rhombic  crystals  ;  melt- 
ing-point, 147°  to  148°. 
For  aqueous  solutions  : 

O]/>      +  83  +  0.07014  />  4 

Water  ......    [a]/,  =  +  88.15°  :> 

Acetate,   C^H^O^CC.!!.^),,.     Monoclinic    prisms  ;  melting- 
point,  117°. 

Benzene  ..........  c       6.243,     t       20°,     [a]/>  ==  110.44°  G 

1  Tollens  :  I^oc.  cit.  ;  Scheibler  :  Her.  d.  chem.  Ges.,  18,  1782. 

*  Ij>c.  cit. 

*  Scheibler  and  Mittelmeier  :  Ber.  d.  chem.  Ges.,  33,  1443. 

1  Villiers  :  Bull.  Soc.  Chini..  37,  98  ;  Alechin  :  Russ.  phys.-ch.  Cles.,  ai,  420. 
'"  Bourquelot,  H6rissey  :  J.  phiirni.  chitn.,  [6],  4,  385. 

*  Alechin. 


CARBOHYDRATES  607 

LUPEOSE,    /f-Galactan,    Ca4HMO21  -f-  H,O(?).     Amorphous. 

A  preparation  dried  in  hydrogen  at  100°  gave  : 

Water p       5,     /        22°,     [a]/,     -.  -    138° 

For  three  different  preparations  which  were  dried  at  110°  to 
115°,  these  values  were  found  earlier  by  Steiger.1 

[»      -  148.7°,     [«]/,  =  +  149-8°,     M/J          147-2° 

If  we  assume  that  the  preparation  dried  at  100°  contains  one 
molecule  of  water  of  crystallization,  the  last  three  results 
would  agree  very  well  with  that  calculated  for  anhydrous 
lupeose.- 

TREHALUM,  C24H42O21,  from  tiehala. 

p  =  0.261  100.365,     /        18°,      [a]/,     ^  -   179°  :! 

GENTIANOSE,  C:J6H66O31(?).     Small  plates  melting  at  210°. 4 

An  aqueous  solution,  prepared  hot,  showed-  •  •   /       18°,     [<*]/>  ^  -f-  65.7° 

cold,      "       ...   /  -----  18°  "    ^4-33.36 

STACK VOSE,  C^H^O.,,.  From  tubers  of  Stachys  tubifera. 
Crystals. 

Water c    ~g        (amorphous  substance),     [<*]/>"-  -p-  146.7° 

"  ••••     ^  =  9-5         (  "  "  ),  "        :=+    H8.8 

"      c       9        (crystalline  ),         "       =  -f-  148.1 

21.  Carbohydrates,  (C6HioO.);; 

AMORPHOUS  SOLUBLE  STARCH. — From  potato  starch  by  heat- 
ing with  glycerol,  water,  dilute  acids,  etc.6 

Water,  c  =  2.533,   I>L  ==  +  206.8°  ' 

"       c  =  2.215,  t  =  17.5,   [nr]y=  211.50°,  from  which  [a]^=z  189.98° 
"       ^^3.995,^^17.5,       "     -211.97,       "  -190.24' 

Other  authors  give  the  rotation    as   [**]/  =  :  -f  216°  ;9  [«]y 
+  211°  ;10  \_a\j  =  -.  -f  216°,  O]/)=:  +  202°.u 

I^andw.  Vers.-Stat.,  36,  423  and  Ztschr.  physiol.  Chem.,  n,  372. 
Schulze :  Ber.  d.  chem.  Ges.,  35,  2218. 
Scheibler,  Mittelmeier  :  Ibid.,  26,  1331. 
Meyer:  Ztschr.  physiol.  Chem.,  6,  135. 
Planta  and  Schulze  :  Her.  d.  chem.  Ges.,  33,  1692  :  34,  2705. 

Zulkowsky  :  id  it/.,  13,1398:  Bechamp  :  Compt.  rend.,  39,  653  ;   Musculus,   Gruber: 
I  bit  ,  86,  1459. 

Zulkowsky  :  Lvc.  cit. 

Salomon  :  J.  prakt.  Chem.,  [2],  28. 

Musculus  :  Jahresber.  (1879),  p.  835. 

Bechamp  :  Compt.  rend.,  39,  653. 

Brown,  Morris,  Millar  :  J.  Chem.  Soc.,   71,  114, 


608         CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

DEXTRINES. 

Crystalline  Soluble  Starch,  Amylodextrine. — Formed  by  the 
action  of  cold  dilute  hydrochloric  acid  or  of  hot  90  per  cent. 
acetic  acid  on  starch,  and  separated  in  crystalline  form  by 
freezing  the  solution.1  Brown  and  Morris2  have  determined 
the  molecular  weight  as  C12H22On  -f  6C12H20O1())  and  give  the 
rotation  as  otj  =  -  -f-  206.5°. 

Achrodextrine. — According  to  the  statements  of  different 
authors,  there  are  several  isomeric  dextrines  formed  under  dif- 
ferent conditions  from  starch.  Musculus  and  Gruber3  dis- 
tinguish three  kinds  : 

fr-Modification [a]    -  -f  210° 

/S-Modification "    :  =  -j-  190 

7-Modification "    -  =  -f  150 

According  to  O' Sullivan,4  there  are  four  different  varieties 
which,  however,  have  the  same  rotating  power.  This  is  given 
as  [a]y=  +  215°  to  217°. 

Brown  and  Heron5  give  [or],-  =  -f-  216°. 

L.  Schulze6  found  the  rotation  of  a  carefully  purified  dex- 
trine as  [a]D=  +  1 86°. 

Lustgarten7  found  for  a  dextrine  obtained  from  dinitro- 
glycogen,/ ==  12.175,  t=  27°,  [>]/,=  +  194°. 

The  rotating  power  of  dextrine  is  increased  by  acids.8 

Water c—  3.714,  /^i7-5°i  [«]./  =  +  215.06° 

Sulphuric  acid,  0.4  p.  c.  ••  €=•  1.064,  t~--  J7-5          "  at  once)  =  -f-  216.5° 

[or]y  (following  day)    =  -f  220.5° 

An  achrodextrine,  (C^H.^OJ.  -f  H2O,  [«]/,==+  183°  is 
described  by  Lintner  and  Dull.9 

Maltodextrine. — By  treatment  of  starch  paste  with  diastase 
above  65°,  [>1  =  +  169.9  to  173.4°  ;in  [ar]y=  +  164.2°." 

1  Musculus  :  Ztschr.  Chem.,  (1869),  p,  446. 

2  Brown  and  Morris  :  J.  Chem.  Soc.,  55,  452. 
8  Ztschr.  physiol.  Chem.,  a,  188. 

*  J.Chem.  Soc.,  35,  770. 

*>  Ann.  Chem.  (Mebig),  199,  243. 
«  J.  prakt.  Chem..  [2],  a8,  327. 

7  Monatsh.  Chem.,  a,  626. 

8  Salomon  :  J.  prakt.  Chem.,  [2],  a8,  42. 

•  Ztschr.  f.  Brauwes.,  17,  339. 

'"  Herzfeld  :  Ber.  d.  chem.  Ges.,  ia,  2120. 
11  Bondonneau  :  Bull.  Soc.  Chim.,  35,  5. 


TKISACCHARIDES    A>'D    POLYSACCHARIDKS  609 

Extended  investigations  on  the  action  of  diastase  on  starch, 
and  especially  on  malto  dextrine,  have  been  carried  out  by 
Brown  and  Morris,1  also  Brown,  Morris  and  Millar.  - 

Artificial    Dextrine.     From    dextrose,    sulphuric  acid,    and 

alcohol. 

[a]/j         -    131  to  134°  :! 

OL        -i2301 

Fermentation  Gum,  dextran,  viscose.  Produced  in  the 
lactic  fermentation  of  cane-sugar. 

[a]/,        —  230°  ;> 
fi-Galactan.     From  Lupinus  luteus. 

Water C-     10,    |>]/,  148.7°  K 

"     f       3.082,     /        15°,     [>]/,         -i48.607 

Shows  no  birotation.  The  rotation  changes  very  little  with 
the  concentration. 

y-Galactan.     In  the  sugar-beet. 

Water c       10,     /       20°,     \ci\,>    --=  4-  238°  B 

€x-Galactin.     In  the  seeds  of  leguminous  plants. 
[«]/>       +  84.6°  « 

GLYCOGEN,  C8H10O5,  or  CMH62O3l.  Found  in  the  liver  of  man 
and  the  herbivora.  The  older  statements  on  the  rotation  of 
glycogen  vary  within  very  wide  limits.  Careful  observations 
were  made  by  Kiilz.1'1  He  states  that  the  concentration  is 
without  special  influence,  and  he  finds  as  the  mean  of  eighteen 
readings  [«],-  —  -)-  211°  (greater  concentrations  than/  —  0.6 
cannot  be  employed).  Landwehr11  found  for  the  glycogen  of 
dog's  liver,  for  t=  18°,  [«],,  =  -}-  213.3°.  Further  values  are: 
[«]/,  =+  196. 33°  " 

200.2  1:J 

1  Ann.  Cheni.  (L,iebig),  231,  72  :  J.  Chein.  Soc.,  55,  452. 

-  J.  Chem.  Soc.,  71,  72,  109,  115. 

Musculus  and  Meyer  :  Ztschr.  physiol.  Chem.,  5,  122. 

*  Konig  and  Schubert  :  Monatsh.  Chem.,  6,  746  :  7,  455. 

^  Stohmann  and  ryangbem  :  J.  prakt.  Chem.,  [2],  45,  305. 

«  Steiffer  :  Ber.  d.  chem.  Ges..  19,  829. 

:  Schulze  and  Steiger  :  I.andw.  Versuchs-Stationen.  36,  4^3. 

•  L,ippmann  :  Ber.  d.  chem.  Ges.,  20,  1001. 
'•'  Miintz  :  Compt.  rend.,  94,  453. 

'"  Jahresber.  f.  Thierchemie  (iSSo),  p.  81  ;  Arch.  f.  ges.  Physiologic.  24,  35. 

11  Ztschr.  physiol.  Chem.,  8,  171. 

12  Huppert  :  Ber.  d.  chem.  Ges.,  27,  Kef.  85. 

13  Kramer :  Ztschr.  fur  Biol.,  24,  100. 

39 


6io 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


CELLULOSE.  According  to  Levallois1  this  is  left-rotating  in 
solution  of  ammoniacal  copper  hydroxide.  But  Bechamp2  gives 
the  direction  as  variable. 

GRAMININ.  Found  in  various  plants  (as  Trisctiim  alpcstrc} . 
White  powder,  melting  at  209°. 

Water />    -  5,     /       12°,     [«]/>--    -  38.89°  :i 

INULIN.  Found  in  the  roots  of  different  plants.  Spheroidal 
crystalline  grains  ;  melting-point,  160°. 

The  older  values  for  the  rotation  vary  between  [#]  „  = 
26°  and  72.42°.     Kiliani4  found  : 


Inulin  from 

Dissolved  in 

p. 

M* 

Inula   Helenium 

(  Water  at  100°  diluted  with  } 
(              cold  water.               ) 

1.5122 

23° 

-  36.66° 

Dahlia    variabil 

l  A  little  potassium  hydrox-  ) 
(     ide  and  then  diluted,      j 

0.9172 

1.7456 

20 
20 

-  37.15 
-  34.10 

Lescoeur  and  Morelle'  found  : 

Water [a]/,  36.94° 

Haller8  gives  : 

Water c       7.25,     [>]/,        -38.8° 

Temperature  and  concentration  appear  to  have  no  influence.7 
Water p       2,       [a]/>        —  37.27°  * 

Inulein. 

Water c       6.6,     [«]/,       -  29.6°  !1 

Pseudo-hnilin. 

Water c       6.64,   [a]/,        -  32.2°  "' 

The   last  two   substances   were   obtained  from    Helta  ti  thus 
tuberosus. 

Bull.  soc.  chim.,  43,  85. 

Ber.  d.  chem.  Ges.,  18,  Kef.  113. 

Ekstrand  and  Johanson  :  Ibid.,,  21,  594. 

Ann.  Chem.  (Uebig),  305,  145. 

Bull.  soc.  chim    33,  418. 

Compt.  rend.,  116,  514. 

Haller. 

Wallach  :  Ann.  Chem.  (Uebig),  334,  368. 

Haller:  Compt.  rend.,  116,  514. 

Haller  :  I.oc.  <  it. 


GUMS  6ll 

IRISIN,  Phlein.  In  the  tubers  of  Iris  pseud-acorus.  Melting- 
point,  218°. 

Water />        10,  /        16°,  [«]/>  =    —51-54° 

/>       10,  *^i6,  —51.15 

P=    5,  '=   !6,  -51-55 

/>         2,  /       22,  -  49.90 

From  Iris p       5,     [(*]/>       —  52.34°) 2 

From  Phleum p  —  5,  —  48.12  J 

LEVOSIX.     In  varieties  of  grain.     Melting-point,   160°. 
Water p  =,  5,      [a]/,        -  36°  3 

LEVULAN.     In  beet-sugar  molasses.     Melting-point,   250°. 
Water c      5  to  30,     /  --  20°,     [a]/,         -  221°  * 

The  temperature  is  without  influence. 
SINISTRIN.     In  the  sea  onion. 

[«]z>  -    -4i.408 
-  34-6°  fi 

TRITICIN.     In  the  roots  of  Triticum  repens. 

[«]/>  =  -43-607 
/      5.  -  41-07° 8 

22.  Gums 

ARABIN,  Arabic  Acid,  C^H^OgC?).  The  principal  constit- 
uent of  gum  arabic  which,  however,  is  a  mixture  of  at  least 
two  gums,  a  right-  and  a  left-rotating  variety.  Pure  arabin 
may  be  made  from  sugar-beets. 

[>]/,  =   -98-509 

WOODGUM,  Xylan,  C5H&O4(?).     In  foliage  trees,  especially 

in  the  birch. 

/>        i  to  2.      [or]/,         -  84°  "' 
[a]/>  usually  =    -  70°  to  85°  " 

Wallach  :  Ann.  Cheni.  (I<iebig),  234,  367. 

Ekstrand,  Johanson  :  Ber.  d.  chera.  Ges.,  ao,  3311. 

Tanret :  Bull.  soc.  chim.,    [3],  5,  724. 

lyippmann  :  Ber.  d.  chem.  Ges.,  14,  1511. 

Schmiedeberg  :  Ibid.,  12,  Ref.  705. 

Reidemeister  :  Jahresber.  Thierch.,  1881,  p.  71. 

Reidemeister :  I^oc.  cit. 

Ekstrand,  Johanson  :  Ber.  d.  chem.  Ges.,  20,  3317. 

Scheibler:  Ibid.,  i,  59 
111  Thomsen:  Ibid.,  13,  2168. 
11  Tollens  :  Handb.  d.  Kohlenhydrate,  II,  202. 


6l2  CONSTANTS  OF  ROTATION  OK  ACTIVE  BODIES 

LACTOSIN,  C^H^O;,,  -f  H..O.  In  the  roots  of  the  caryophyl- 
laceae.  Small  crystals. 

Water p    -2.907    (for  the  anhydrous    substance),   /       16°,    </'7-5 

1.0128,   [>]/>        -f  211.7°  l 

23.  Camphors  and  Terpenes 

In  the  nomenclature  and  classification  of  the  following  com- 
pounds, the  fundamental  work  of  Wallach  has  been  taken  as 
the  guide.  The  terpenes  are  therefore  divided  into  four 
groups : 

A.  Aliphatic  terpenes, 

B.  Terpan  group, 

C.  Camphan  group, 

D.  Poly  terpenes, 

and  at  the  beginning  of  each  group  the  hydrocarbons  will  be 
treated,  then  the  alcohols,  ketones,  and  so  on. 

A.    ALIPHATIC  TERPENES 

i.   Hydrocarbons 

LICARENE,  C10H16.     Boiling-point,  176°  to  178°. 
d°      0.8445,    t      20.2°,    [>]/,       4-  7.85° s 

2.  Alcohols 

^-LiCAREOL,  Coriandrol,  CIOH,.OH.  Boiling-point,  196°  to 
198°. 

if"       0.8820,     [<r];,  15.2' 

Boiling-point,  93°  to  94°   (15.5  mm.). 

dtt  0.882,     |>]^"»       r  15-02  4 

/-LiCAREOL,  /-Linalool,  Aurantiol,  Lavendol,  Nerolol, 
CIOH17OH.  Boiling-point,  199°  to  200°. 

d"       0.8819.     </''•'       0.8662,     [«r]}5-4         -  18.35°  :> 
d"      0.868,     [a]^        -19— 

IManta  and  Schnlzc  :  Her.  d.  chem.  r.es.,  23,  1692. 

Harhier  :  Compt.  rend.,  116,  993. 

Barbier:  Ibid.,  116,  1459. 

Barbier  :  Hull.  soc.  chim.,  [3],  9,  914. 

Barbier  :  Compt.  rend.,  114,  674. 

Morin  :  I  hid.,  pa,  998. 


CAMPHORS    AND   TERPENES  613 

According  to  Barbier,  licareol  and  linalool  are  not  identical. 
He  gives : 

I- Linalool.     Boiling-point,  98°  to  100°  (14  mm.) 
d"      0.8869,     [«]*?•<       -  11.91°  > 

Boiling-point,  86°  to  87°  (14  mm.). 

d'M       0.8622,     [«]=•;•        -  19.62°  - 

</-RHODINOL,  d-Citronellol,  C10H1TOH. 

From /-linalool-acetate.     Boiling-point,  123°  (14  mm. ). 

rf°  •--•-•  0.902 1.    [a]/>      —  i.9°3 

From  citronellal.  (Formula  given  :  C10H19OH.)  Boiling- 
point,  117°  to  118°  (17  mm.). 

rf'7-s        0.8565,      [>]£.5  =  -j-  4.0 

Acetate,  C^H.,,,0,.     Boiling-point,  119°  to  121°  (15  mm.). 

</'7o   =  0.8928,        [a];;-5       ,   -     2.37* 

Geraniol  is  identical  with  rhodinol,  according  to  Bertram 
and  Gildemeister  ; '  and  according  to  Bouchardat6  and  Tiemann 
and  Semmler7  licarhodol,  also,  for  which,  however,  Barbier8 
gives  the  following  constants  : 

Licarhodol,  CUIH17OH.     Boiling-point,  122°  (19  mm.). 

d"  =  0.8952,     O]~-4       -  0.69° 
Acetate.     Boiling-point,  135°  (21. 5  mm.). 

d"  =  0.9298,     [a];?-*  =    —  0.28° 

/-RHODINOL,  1-Citronellol,  C10H17OH. 

From  German  rose  oil.  a?13  =  0.8838.  Boiling- point,  216° 
<no°  to  1 20°  at  12  mm.). 

[<x\D=   -2.809 

From  Turkish  rose  oil.     d"    -  0.8896.     Boiling-point,  124° 

{16  mm.). 

[a]/?  =    -  2.62°  "' 

1  Bull.  soc.  chim.,  [3],  9,  1004. 

-  Tietnann  :  B«r.  d.  cheni.  Ges.,  31,  834. 
'•'•  Barbier  :  Bull.  soc.  chim.,  [3],  9,  1004. 

4  Tiemann,  Schmidt  :  Ber.  d.  chem.  Ges.,  39,  906. 

5  J.  prakt.  Chem.,  [2],  49,  185. 

6  Compt.  rend.,  116,  1254. 

'•  Ber.  d.  chem.  Ges.,  36,  2714. 

-  Compt.  rend.,  116,  1253. 

"  Eckart  :  Arch.  d.  Pharm.,  339,  355. 
"'  Barbier:  Compt.  rend.,  117,  1092. 


614  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Boiling-point,  110°  (10  mm.). 
<f>z=  0.8731,  [a]D  •.--  -  2.11°  ! 
t/20  —  0.8612,  [«]£  =  —  4-33  2  Formula  given  as  C10H19OH. 

From   Bulgarian  rose   oil.      d™  =  0.8785.      Boiling-point, 

224.7°. 

[*]*=    -3.22°' 

From  French  geranium  oil.     d°  =  0.8886.       Boiling-point, 

124°  (14  mm.). 

[«]„:_-   -2.5°* 

3.   Aldehydes 

CITRONELLAL,  Cj0H18O.  From  melissa  and  citronella  oils. 
Boiling-point,  205°  to  208°  (103°  to  105°  at  25  mm.). 

<f17'5  ±=  0.8538,     [«]£-s  =  +  12.50°  5 
Boiling-point,  202°  to  207°. 

d*'^    0.8509,     [«]/>  =-.  +4.80(i 

B.    TERPAN  GROUP 

i.  Hydrocarbons 

*/-LIMONENE  (Citrene,  Hesperidene,  Carvene),  C10H16.  In 
oils  of  orange  peel,  citron,  bergamot,  cumin,  erigeron,  and 
dill.  Boiling-point,  175°  to  176°.  d™  =0.846. 

Chloroform  ...  p  =  14.38,     rf8  -..=  1.353,     [«]«,  =  -f  106.8°  ' 

Derivatives:  Hydrochloride,  C10H16HC1.  Boiling-point,  97° 
to  98°  (n  to  12  mm.). 

rf17'8  =  0.973,     [nr]jj-«  -  +  39-5°  8 

Tetrabromide ,  C,0H16Br4.  Rhombic-hemihedral  crystals  ; 
melting-point,  104°. 

Chloroform  . . .  p       14.24,     d9  =  1.555,     [a]^  a=  -f  73.27°  9 

a-Nitrosochloride,  C10H16NOC1.  Crystals ;  melting-point, 
103°  to  104°. 

Barbier,  Bouveault :  Compt.  rend.,  laa,  529. 
Ticmann,  Schmidt :  Ber.  d.  ch^m.  Ges.,  39,  923. 
Markownikoff,  Reformatzky  :  J.  prakt.  Chem.,  [2],  48,  299. 
Monnet,  Barbier:  Compt.  rend.,  117,  1093. 
Tiemann,  Schmidt :  Ber.  d.  chem.  Ges.,  39,  905. 
Dodge  :  Ibid.,  33,  Ref.  175  and  34,  Ref.  90. 
Wallach,  Conrady  :  Ann.  Chem.  (Uebij?),  353,  144. 
Wallach  :  Ibid.,  270,  189. 
Wallach,  Conrady  :  Ibid.,  353,  145. 


CAMPHORS  AND  TERPENES  615 


Chloroform  ----  p=  21.13,     dr>    r^  J-379.     [«]/?   = 
Chloroform....  />  =  13.30,     </'•'•*        1.441,     [a]*8  =  -f  313.4°''- 

fi-Nitrosochloride.     Crystals;  melting-point,  105°  to  106°. 
Chloroform.  .  .  .  p  =  5.339,     rf10-5  =  1.476,     [a]£-s  =  -f  240.3°  3 

BenzoylNitrosochloride,  (C10H15NOC1)COC6H5.  (The  same 
benzoyl  compound  is  formed  from  the  two  nitrosochlorides.  ) 
Rhombic  crystals  ;  melting-point,  109°  to  110°. 

Aceticether  ----  p  =  3.46,     </*0'5  —  0.906,     [or]*°-s  —  -f-  101.75°  4 

a-Nitrolanilide,  C10H1S  (  NO)  (  NHC6H5  )  .   Monoclinic  crystals; 
melting-point,  112°  to  113°. 
From  ar-nitrosochloride  : 

Chloroform  ......  />  =  5.35,     du   =  1.445     M/j  ==  +  102.19° 

From  /?-nitrosochloride  : 

Chloroform  ----  p  =  7.071,     rf19'2  =  1.439,     l<*~\%''  =  +  102.25° 

Nitroso-a-nitrolanilide,  CltHM(NO)[N(NO)CtHJ.   Crystals; 
melting-point,  142°. 
Ether  or  benzene  ?  ........  p  -—  4.208,     ^19'8  —  0.805,     [tr]^-8  =  -f  46.20° 

p-Nitrolanilide.     Matted  needles  ;  melting-point,  153°. 

From  «-nitrosochloride  : 

Chloroform  ----  p  =  5.086,     (f24   =1.447,     [«]*•    =     —88.33° 

From  /?-nitrosochloride  : 

Chloroform-  .  .  .  p  =  5.133,    rf19'4  =  1.447,     [«]^"»  =   -  89.39°  5 

a-Nitrolbenzylamine,     C10H16(NO)NH.CH2C6H5.     Needles  ; 
melting-point,  93°. 
Chloroform  ................  p  =  7.027,  ^9'5   =1.459,  C^]^5  =+i63.8°6 

Hydrochloride  in  dil.  alcohol/*  =  3.  975,  rf10    =0.906,   [a\™   -      -   82.26 
Nitrate  "    "          "      p  =  1.034,  dn     =0.900,   [n:]1^   =      -    81.0 

^/-Tartrate  "      />=  1.133,  rf1*-5  =  0.900,  [<*]£•*=    -   49-93 

/-Tartrate  "      /  =  0.968,  rf10'5  =  0.899,   [o:]»-s=    -    69.9 

Hydrochlor-nitrolbenzylamine,  C10II16HC1(NO)NHCH2C6H5. 
Xeedles  ;  melting-point,  103°  to  104°. 

Chloroform  .....  p  =  2.403,     rf18'5  =  1.47,     [nr]g-s  =  -f  149.6°  7 


1  Wallach  :  Ann.  Chem.  (lyiebig),  246,  224. 

-  Wallach,  Conrady  :  Ibid.,  252,  145. 
3  Wallach,  Conrady:  Loc.  cit. 

«  Macheleidt  :  Ann.  Chem.  (Uebig),  270,  176. 

•  Wallach  :  Ibid.,  270,  171. 

6  Wallach,  Conrady  :  Ibid.,  252,  148. 
'   Wallach  :  Ibid.,  270,  192. 


6l6  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

a-Nitrolpipcridinc,   C10HI6(NO)NC-H10.     Rhombic  crystals; 
melting-point,  94°. 

Chloroform  .....  />       3.146,     rf"          1.475.   [a];;      --4-67.75° 

fi-Nitrolpiperidine.       Monosymmetric      crystals  ;      melting- 
point,  110°. 

From  oMiitrosochloride  : 
Chloroform  .....     />       3.107,     </'J-:>        1.478,     [cjr]*s  -      —60.48° 

From  /f-nitrosochloride  : 
Chloroform  ......  />       2.1104,  dr-         1.478,     [«"]'/;   =     —60.37°' 

Carvoximc,  Isonitrosoterpene,  C10HUNOH.      (By  splitting  off 
HC1  from  a-  or  /f-nitrosochloride.  )     Crystals  ;  melting-point, 
72°. 
Alcohol  ........  p       4-328,     d       0.8025,     /        18°,     [a-]/,        -39-34°' 

Benzoyl  Compound.     Crystals  ;  melting-point,  96°. 
Chloroform  .....  p       5.716,     dn        1-4455,     O]p        -  26.97°  :>> 

Benzoyl-hydrochlorcarvoxime,  CIOHHNO.CO.C6H,.HC1.  Crys- 
tals ;  melting-point,  114°  to  115°. 

Acetic  ether  ......  p       1  1.866,     rf2"  •     0.926,     [a];;       -   9.92°  4 

/-LiMONENE.       In   pine  needle  oil.     Boiling-point,  175°   to 
176°.     d™  =  0.846. 
Alcohol  .......  p       6.126,     d?       0.795,     [a-]/,        -  105.0°  r> 

Chloroform....  p       14.3     rf10'5       1-353,     *       10.5°,     [a]10-'        -  105°  fi 

Derivatives:  Hydrochloridc.     Boiling-point,   97°  to  98°  (11 
to  12  mm.). 


Tetrabromide  .       Rhombic-hemihedral     crystals  ;       melting- 
point,  104°. 

Chloroform  ......  p       12.85,     </3       1.5525,     O]';,  73-45°' 

a-Nitrosochloride.     Crystals  ;  melting-point,  103°  to  104°. 
Chloroform  .......  />       0.993,     d*       1.496,     [a~\J,       —314.8° 

1  Wallach,  Conrady  :  Loc.  cit. 


•  Wallach  :  Ann.  Chem.  (Uebig),  346,  227. 

3  Wallach,  Conrady  :  IMC.  cit. 

4  Wallach,  Macheleidt  :  Ann.  Chem.  (Uebig),  370,  179. 
'-  Wallach  :  Ibid.,  246,  222. 

'•  Wallach,  Conrady  :  I^oc.  cit. 

'  Wallach  :  Ann.  Chem.  (Uebig),  370,  189. 

*  Wallach.  Conrady  :  /»r.  cit. 


CAMPHORS  AND  TERPENES  617 

ft-Nitrosochloride.     Wooly  needles  ;  melting-point,  100°. 
Chloroform />       0.99*8,     d*-:>        1.495,     [«"]^,5  —   —  242.2°  ' 

Benzoyl  Nitrosochloridc.     Crystals;    melting-point,    109°   to 
110°. 

Acetic  ether.  ../>       4.828.     d™-:>       0.911,     [«]£-s  •     —  101.84°'- 

ct-Nitrolanilide.        Monosymmetric    plates  ;      melting-point, 

112°  tO  113°. 

Chloroform p       7-344,     d™'4       1-437,   [>];?••»        -102.62° 

Nitroso  Compound.     Crystals  ;  melting-point,  142°. 

Chloroform p       4.291,     </19-v  -   0.804,     Mj?'*~  ~  47-82° 

(i-Nitrolanilide.     Matted  needles  ;  melting-point,  153° 

Chloroform p       6.117,     ^1M'4  =  1.444,     M#'4  =  -+-  87.17° 

Xitroso  Compound.   Crystals  ;  melting-point,  129°.    Inactive.' 
(\-Xitrolbcnzylaminc.     Needles  ;  melting-point,  93°. 

Chloroform /  6.829,  ^9'5   —1.460,  [«]%s   -    — 163.6° 4 

Hydrochloride.  dil.  alcohol-  p  3.274,  d]"-:>       0.899,  [a]™-s  -  —  83.06 

Nitrate  />  1.019,  a"1"'       0.898,  [a]g*  .= .-f  81.0 

^/-Tartrate  />  1.378,  </12-:>       0.902,  [n-]jf-s  = -f-  69.6 

/-Tartrate  p  1.119,  ^n          0.901,  [«]'/,       = -f  51.0 

Hydrochlornitrolbenzylamine.      Needles  ;  melting-point,  103° 
to  104°. 
Chloroform p       2.431,  cf]^:>        1.469,  /        18.5°,   [n:]g-5.=    -  147.4°  5 

u-Nitrolpipcridine.     Rhombic  crystals  ;   melting-point,   94°. 
Chloroform /       3-"3,     rf11'7    --  1-475,     [^V/\'7 "-'-   -67.60° 

fi-Nitrolpipctidine.     Monosymmetric  crystals;  melting-point, 
110°. 

Chloroform p       3.051,     </"-5  -      1.476,     [a]^o        —  60.18°  e 

Carvoxime.      From   the  nitrosochloride   (or  from  ^-carvol). 
Melting-point,  72°. 

Alcohol p        9.846,     rf17-- 0.8146,      [rr]}J        -7-  39.71°  7 

i  Wallach,  Conrady  :  Loc.  cit. 

-  Macheleidt  :  Ann.  Chem.  (Uebig),  370,  176. 

Wallach  :  Ibid.,  270,  185. 
4  Wallach,  Conrady :  Loc.  cit. 
'••  Wallach  :  Ann.  Chem.  (I,iebig),  270,  192. 
••  Wallach,  Conrady  :  Loc.  cit. 
'  Wallach  :  Ann.  Chem.  (Iyiebig),  246,  227. 


6i8 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Benzoyl  Compound.     Crystals  ;  melting-point,  96°. 
Chloroform p  ^  5.765,     dr'  ==  1-4545,     [<*]}?  »  +  26.47°  ! 

Benzoyl  Hydrochlorcarvoxime.  Crystals ;  melting-point, 
114°  tons0. 

Acetic  ether. . . .  p  =  3.157,     d™'~  =  0.907,     [a] £.7        -  10.58°  • 

Goldschmidt  and  Freund3  have  prepared  the  following  deriv- 
atives from  the  df-carvoxime  ([«]/>—  +  39-62°).  Solutions 
in  chloroform. 


.     P- 

</'. 

/. 

Mi- 

2.7205 

2-7547 
2.7402 
2.7106 
9-1058 
9.1942 
10.0169 
9.2950 
7.7806 
5.4687 
5.5132 
5.4965 
4-5575 
4.5845 
4-5648 

1.4773 
1.4755 
1.4763 
1.4729 
1.4426 

1.4423 
1.4363 
1-4395 
T-4373 
1.4729 
1.4692 

1.4709 
1.4647 
1.4625 
1.4656 

18° 

18 
18 

20 
l8-5 
15.5 
15.5 
15-5 
22 
22 
23-5 
23 
23 
23-5 
22.5 

+  31.67° 

+  27.40 
-f  29.79 
+  30.75 
-f  26.64 
+  27.08 
-f  26.86 

—  L  23  A.A. 

Carbo-0-toluidocarvoxime   

+  40.63 
+  25.96 

-f  18.24 

-f  14-90 

0.0 

+  20.68 
+  17-33 

w-Nitrobenzoylcarvoxinie  

For  further  data  on  carvoxime  derivatives,  see  Goldschmidt 
and  Fischer.4 


</-SYLVESTRENE , 

turpentine.     Liquid. 


C,0H 


In  Swedish  and    Russian  oil  of 
Boiling-point,  175°  to  176°. 


dl«  =  0.8510,     [a]^  =  +  19.5°  - 
Boiling-point  171°.     d16       0.8653,     [a])5     :  -f  17°  « 
Chloroform p       14.316,     rf10  a±  1.351,     |>]£  —        66.32°  7 

Wallach,  Conrady  :  IMC.  cit. 

Wallach:  Ann.  Chem.  (Uebig),  370,  179. 

Ztschr.  phys.  Chem.,  14,  398. 

Her.  d.  chem.  Ges.,  30,  2069. 

Atterberg  :  Ibid.,  10,  1206. 

Tilden  :  J.  Chem.  Soc.,  33,  80. 

Wallach.  Conrady  :  Ann.  Chem.  (L,iebig),  253,  149. 


CAMPHORS  AND  TERPENES  619 

Derivatives :  Dihydrochloride,  C10H16, 2H Cl .  Monosymmetric 
crystals  ;  melting-point,  72°. 

Chloroform />       14.20,     d%  =  1.4235.     O]^  =  +  l8-99° 

Dihydrobromide ,  C10H16,2HBr.  Monosymmetric  crystals; 
melting-point,  72°. 

Chloroform />=  4-359.     ^'5       J-499,     M&s  =  +  17^9° 

Tetrabromide,  C10H16Br4.  Monosymmetric  crystals  ;  melting- 
point,  135°. 

Chloroform p  =  4-338,     d?'h  =  1.517,     [a]*?  =  -f  73.74° 

Nitrolbenzylamine,  C10H16NONH.C7H.  Crystals  ;  melting- 
point,  71°. 

Chloroform p=  1.908,     d*'*  =  1.495,     [«]%5  =  -  185.6° 

Nitrolbenzylamine  Hydrochloride,  C]0H16NONHC7H.HC1. 
Crystals. 

Dil.  alcohol p=  1.571,     d~*  =  0.904,     [a]^s  =  +  79.2°  ] 

/-SYLVESTRENE.  From  Finns  Abies.  Liquid  ;  boiling-point, 
170.3°. 

d™  =  0.8664,      [nr]<°  =    -  18.3°  - 

^/-PHELLAXDRENE,   C10H16.      In  bitter  fennel  oil,  elemi  oil 
and  resin.     Liquid  ;  boiling-point,  171°  to  172°. 
</io  =  0-85585     [a],o  ^  4.  1?>64o  5 

Derivatives :  Diphellandrene ,  CMH32.  Made  by  heating 
phellandrene  for  twenty  hours  to  140°  to  150°.  Melting- 
point,  86°. 

Chloroform ^^=5.65,     [>]/>  =  -f-  82.9°  4 

Nitrite,  C10H16(NO)NO2.     Melting-point,  94°. 

Chloroform [«]/>=    -  183.5°  5 

t/-MENTHENE  (hydromenthene) ,  C10H1S.  By  splitting  off 
water  from  /-menthol.  Liquid  ;  boiling-point,  167.4°. 

d»  =  0.8073,     [a]»  =  + 10.66°.     ([a]y  =4-  13-25)  6 

Wallach,  Conrady  :  Loc.  cit. 

Kuriloff  :  J.  prakt.  Chem.,  [II],  45,  126. 

Pesci  :  Ber.  d.  chem.  Ges.,  19,  Ref.  874. 

Pesci  :  Loc .  cit. 

Pesci  :  Loc.  cit. 

Atkinson,  Yoshida  :  J.  Chem.  Soc.,  41,  53. 


620  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Boiling-point,  167°  to  168°. 

d'M      0.814,     [«]-      Jf  26.40°  ' 

Boiling-point,  167°  to  168°. 

[«]/>        •  53-53°  •-' 

/-MENTHENE.     By  splitting  off  hydrochloric  acid  from  the 
right-rotating  menthyl  chloride.     Liquid  ;   boiling-point,  170° 

to  171°. 

(TM       0.816,     [<r]/, 

2.   Alcohols 


/-MENTHOL,  Menthacamphor,  C10Hi»OH.     In  oil  of  pepper- 
mint.    Crystals;  melting-point,  42°  ;  boiling-point,  211.5' 
Alcohol c  -  -  10,     [<r] 


-  50.1°)  4 

-  49-4  ) 


20,     d*   =  0.8115,     [«]£       -  49-35°);' 


P       10,     d*>    -0.8845,     [ar]=°  -   -50.59 

For  menthol  of  American  origin    (Michigan),   Long  gives 
the  following  values,  holding  for  q  ==  30  to  92. fi 

Melted d^-6       0.8810,     t  =  46°,     [>]/>        —49.86° 

Alcohol /       20°,     [a]/>  48.247  — o.oi 1 108  q  —  0.00001870?* 

Benzene /       20°,         "  —  49.511    |   0.025634  ? —  0.0008403   g* 

-f- o.oooo 1 1 02  ?5 
Glac.  acet.  acid  /       20°,         "  —  47.711    -0.006386? —0.000071 42?' 

Derivatives  :  Carbonate,   (CIOHI9).,CO3.     Mother-of-pearl-like 
crystals  ;  melting-point,  105°. 

Benzene p       2.021,     [a];j         -  92.52°  ~ 

Urethane,    C10H19O.CO.NH,.       Rhombic  needles  ;    melting- 
point,  165°. 

Chloroform p       0.58,     [^J^j  —    —  85.11°  ' 

Sucdnic  Add  Monoester,  COOH.C.,H4.COOCIOH19.     Crystals; 
melting-point,  62°. 

Benzene p  ~  1.375,     O]/V        —  59-63°  !l 

Sicker,  Kremers  :  Am.  Chem.  J.,  14,  291. 

Slavinsky  :  J.  russ.  chem.  Ges.,  39,  118. 

Berkenheim  :  Ber.  d.  chem.  Ges.,  35,  690. 

Arth  :  Ann.  chim.  phys.,  [6],  7,  438. 

Beckmann  :  Ann.  Chem.  (I«iehig),  350,  327. 

J.  Am.  Chera.  Soc.,  14,  149 ;  Chem.  Centrlhl..  is.^2,  II,  525. 

Arth  :  Loc.  cit.,  p.  470. 

Arth  :  Loc.  cit.,  p.  464. 

Arth  :  Ijoc.  cit..  p.  4Sj. 


CAMPHORS  AND  TERPENES 


621 


Succitiic    Add  Dicster,  C2H4(COOC10H1!()L,.       Rhombic  octa- 
hedra  ;  melting-point,  62°. 

Benzene p  —  1.87,     [«]™        —  81.52°  ' 

PhthalicAcidMonoester,  CfiH4(COOH) (COOC10H19) .     Micro- 
scopic needles  ;  melting-point,  110°. 

Benzene p  —  1.575,     Oil?        ~  IO5-55°  2 

Phthalic  Add  Diester,   CttH,(COOC10H19),.     Rhombic    crys- 
tals ;  melting-point,  133°. 

Benzene p       2.006,     [<i]™  _-   —  94.72°  3 

Benzole  Acid  Ester,    C^H^COOC^H,,.     Crystals  ;    melting- 
point,  53°  to  54°. 

Benzene p  —  0.953,     [ar]*°  =   —  90.92°  4 

Alcohol p  =  20,         <P°  =-  0.8312,     [<*]»  =    —  86.41°  5 

Alcohol p  =  20,     [«]/?  =  —  90. 72°  * 

Goldschmidt  and  Freund7  prepared  the  following  derivatives 
from  menthol  (  \a\  D  =  —  50.  i )  : 


i 

A                        dt.                    t.              [«]/;. 

Phenyl 
o-Tolyl 
m-  " 

P-     " 

carbamic  acid  ester  ..      5.6085            1.4486           20°         —77.21° 

".:••     5-6157         1-4436        21       —65.88 

"     ••      5-5791            1.4428           21.5,     —71.43 
"        "     ..      5.6177            1.4437           21          -72.30 

L.  1 

[\schugaefF  has  made  the  following  determinations  : 

</r-        [«K. 

"       propionatc  o  0184                 7s  si 

**       //-caproatc  •••••••••••        o  oo^^                 62  07 

"        «-caorvlate.  .                         0.8077            —  «;«;.2«; 

Arth  :  Z^?c.  «V.,  p.  482. 

Arth  :  Zoc.  «'/.,  p.  488. 

Arth  :  IMC.  ct't.,  p.  486. 

Arth  :  Loc.  cit.,  p.  481. 

Beckmann,  Pleissner  :  Ann.  Chem.  (I,iebig),  362,  33. 

Beckmann  :  J.  prakt.  Chem.,  [Ill,  55.  i?- 

Ztschr.  phys.  Chem.,  14,  397. 

Ber.  d.  chem.  Ges.,  31,360. 


622  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

</-TERPIXEOL,  C10H17OH. 

a.  Liquid;  boiling-point,  213.7°   to  217.7°  ;  dw'*  -—  0.9189. 

[tr]£5  =  -f  48.4°  » 

b.  Crystalline  ;    melting-point,     32°  ;     boiling-point,     120° 
(20  mm.). 

In  fused  condition,  [or]  „  =  -J-  19.08°. 

Alcohol [a]/,  =  +  85.53°  " 

/-TERPINEOL. 

a.  Liquid  ;  boiling-point,  217.7°  to  220.7°  ;  d^  =  0.9201. 

MV-  -56.2°:< 

In  alcohol-sulphuric  acid  solution,   the  rotation  sinks  very 
rapidly  and  may  finally  disappear  entirely.4 

Boiling-point 218°  to  223°,     d°  —  0.961,     [a']^—  —  64.05  :> 

b.  Solid  ;  melting-point,  32°  ;  boiling-point,  220°. 
In  melted  condition  d"  —  0.9533,  \.a~\D  ~      -  80°. 

Alcohol [>]/,  =    —  92.32°  r> 

Melting-point,  32°  ;  boiling-point,  215°  to  218°. 

|»  =    -  117.5  7 

Derivatives:  Formate,  C10H,.OCOH.     Liquid  ;  boiling-point, 
135°  to  138°  (40  mm.). 

d"      0.9986,    [or],,  =   -  69.25°  H 

ISOPULEGOL.     Boiling-point,  91°  (13 mm.). 

</17""'--=  0.9154,     [aty*        -  2.66°  * 

j.  Amine  Bases 

</-MENTHYLAMINE,  C10H19NH2.    Liquid  ;  boiling-point,  206° 
to  207°.     By  reduction  of  the  oxime. 

Alcohol p  —  10.78,     d°o  =  0.8749,     [a]o  =    -•  9.26°  1U 

Flawitzky  :  Ber.  d.  chem.  Ges.,  20,  1959. 
I.afout .  Ann.  chim.  phys.,  [6],  15,  204. 
Flawitzky  :  Ber.  d.  chcm.  Ges.,  la,  2355. 
1  -lawit/ky. 

Buchardat,  I.afont :  Compt.  rend.,  ica,  435. 
Lafont  :  Ann.  chim.  phys..  [6],  15,  186.  204. 
Krtschikowsky  :  J.  russ.  chem.  Ges.,  a8,  137. 
I.afont  :  Bull.,  49,  325. 

Tiemann,  Schmidt :  Ber.  d.  chem.  Ges.,  39,  903. 
"'  Negoworoff  :  Ibid.,  35,  621. 


CAMPHORS  AND  TERPENES  623 

From  /-menthone  by  ammonium  formate.    Liquid  ;    boiling- 
point,  205°. 

d''       0.866,         [a]6^  =- -f  14.71°  ' 
Alcohol c  -----  12.7016,     [a]^  =  -f    8.22°- 

Derivatives :  The  following   determinations   have  all   been 
made  by  Binz  :  :' 

Hydrochloride,  C10H19NH,.HC1.  Prisms  ;  melting-point,  189°. 

Water />        2.77,       dr>     -1.0022,       [n:]^      =  -f  17.24° 

Ether p  =  1.71,       d*     -0.73,          M«,  :-=  +    8.34° 

The  rotation  of  the  solution  does  not  change  on  standing. 

Hydrobromide.     Small  needles  ;  melting-point,  224°. 

Water p  .• .-.  1.30,       d"      -1.03,       [«]£    :  13.83° 

Ether p  =-  1.36,       rf11*  =  0.729,     [<r]«-s  =  -f    5.26° 

Hydroiodide.     Crystals  ;    melting-point,    270°    (with  decom- 
position). 

Water />       2.75,       rf14"'  =  1.009,     O]/?'5  =  +  ii-79° 

Formyl     Compound,     CU,H1MNH.COH.     Crystals;     melting- 
point,   116°  to  117°. 

Acetic  ether. . .  p  =  1.83,       dv-     -----  0.9132,   [<r]»       =  -  50.89° 

"     ...p  =  i. 809,     dl-     =0.9128,   [or]«  49.98 

Chloroform  ...p  =  5.39,       d4       -  1.458,     [«]^  4-n 

•  •  •  p  =  5-36,       </:>       -  r.459,     [«]3/,       ^  +  53.96 

Methyl  alcohol  p  =  7.16,       d"     =0.812,     [a]»  63.30 

Acetyl  Compound,      C10H19NH.COCH:r     Prisms  ;     melting- 
point,   166°  to  167°. 

Acetic  ether...  p  =  1.77,  dr'  =  0.9124,   [cr]^  =  -f.  44.71° 

"     ...  p    -1.42,  d"<  -0.9132,  [a]^  z  =  T-45-48 

Chloroform  ..-/>       4.40,  fl"  1.468,     [o:]^  50.57 

...  p     .  1.89,  </•  -1.493,     [«-]*/,  51.84 

Methyl  alcohol  p  -.  5.39,  rflft  =0.810,     [a]1;;  ^  +  48.80 

Propionyl  Compound,  C10H19NH.COC,H5.    Crystals  ;  melting- 
point,  150°. 

Acetic  ether...  p   ^1.84,  d}-  ==0.9134,  [«]y;  40.45° 

"     ...  p  ----1.807,  dv-  =0.913,  [a]«  39.56 

Chloroform  ...p  =  5.51,  ^  ^  1-453,  [«]/,  45-14 

. ..  /  =  2.7,  d*  =  1.449,  [«]/,  =  +  46.48 

Methyl  alcohol  p       7.19,  rf"  =0.8125,  [a]»,  .  =  -f  54.3° 

1  Wallach,  Binz  :  Ann.  Chera.  (Liebig),  376,  324. 
-  Binz  :  Ztschr.  phys.  Chem.,  12,  727. 
;  Ibid.,  12,  727. 


624  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Butyryl  Compound,  CK.H19NH.COC:tH..  Crystals  ;  melting- 
point,  105°. 

Acetic  ether...  />  =  1.78,       d}"":'       0.9114,  [<T]^-S        -j_  35.64° 

Chloroform.-./*       4.88,      d*           1-457,  MJ,               40.59 

/-MENTHYLAMINE,  Liquid;  boiling-point,  204°.    d»  —-  0.8685. 
Alcoholic  solution c  ?    [<*]/>  =        33°  ' 

Boiling-point,  205°.     d~  =  0.860. 

Without  solvent Mj>  =    -  38-o?  2 

Alcohol £-^=11.269,     [<*]>,        —  31.90  :1 

Derivatives  :    Hydrochloride.     Crystals  ;     decompose     above 
270°. 

Water p --=  2.99,      rf1!l  =  i.oor,     [a]£  =  -j-  35.66° 

/    -3-2          </•-"'       0.998,     [a]-    =  +  35.56 

Hydrobromide.     Needles  ;  decompose  abov£  200°. 

Water p       2.963,     d1-        1.007,     M"   -    -29.32° 

Hydroiodidc.     Crystals  ;  decompose  above  200°. 

Water p       2.79,       dvi       1.009,     O]j;        -  24.72° 

Formyl  Compound.     Crystals  ;  melting-point,  102°. 


Acetic   ether...  p  =  2.19,     dl°''a  —0.913,     [or]};3 

-  76.44° 

"     ...  ^  =  2.17,     d"       =  0.9135,   M}j 

-  76.49 

Chloroform  p  —  5.25,     rfK           1-457,     M/, 

-  83.78 

....  />       5.22,     d**   -31.4555,   M8/,5   - 

-  82.97 

.../>=  1.39,     rf*-3   :     1.486,     M8/,5   -z 

-  82.09 

Methyl   alcohol/       7.44,     d™     -:  0.8131,   [a]))' 

~  83.43 

Acetyl  Compound.     Crystals  ;  melting-point,  143 

0  to  144°. 

Acetic  ether...  p  ^2.16,     d™         0.9118,   M/} 

-  76.27° 

...  p    -  2.06,     ^l:>          0.9117,   [<t])J 

76.89 

Chloroform  ..../>       5.36,     d*            1.4525,   [tf]9; 

-81.73 

••••  />-  -5-34,    ^10        1-4515,  My; 

-81.90 

....  >        1.48,     f/IJ       =  1.483,     [tr]5, 

—  82.29 

Methyl   alcohol  />       2.52,     d*           0.805,     [al9> 

83.64 

"     />    -7.38,   rf10    -0.8133,  C«3s 

85.67 

Propionyl  Compound.      Crystals  ;   melting-point, 

88°  to  89° 

Acetic   ether...  p       2.13,     d"         0.911,      [«]J3 

-  67.26° 

Chloroform  />       5.^,     d*       r-  1.462,      [«]5, 

-  67.53 

Methyl    alcohol  />     :  8.93,     rf«       =  0.8148,    [>]«, 

78.02 

l\thyl  alcohol  .  .  p   =  2.6,       rf           0.8045,    [tr]^ 

76.02 

1  Andrew.  Audreeff  :  Bcr.  d.chem.  Ges.,  35,  620. 

*  Wallach,  Bin/  :  Ann.  Chem.  lUebij?),  376,  323. 

3  Bin/.  :  /tuchr.  phys.  Chem.,  la,  728. 

CAMPHORS  AND  TERPENES  625 

Butyryl  Compound.     Crystals;  melting-point,  80°. 

Acetic   ether...  p  ^  2.22,     dvi     -^0.9122,    [«]»          -63.58° 
«    .../  =  2.i9,     rf12'5  —0.9119,    [^]yf5  =    —  64-75 
Chloroform....  />  -4-47,     rf4       =1.464,      [«]/,  -72.10 

"        ..../>    ,2.69,     rf4        -1.479.      M4,,  -70.87 

The  above  determinations  all  by  Binz.1 

The  base,  CMIH,,N2C1,  has  been  made  by  Wallach  by  treat- 
ment of  iso-/-menthonoxime  with  PC15  in  chloroform  solution. 
Melting-point,  59°  to  60°. 

Alcohol  ....  p-=  2.17,     rf20  -  0.7975,     [*]£  -    -  l86-35°  J 

4.  Ketones 

</-MKNTHONE,  C10H18O.  From  menthol  by  oxidation. 
Liquid  ;  boiling-point,  208°. 

rf12  =  0.9000,     [cr]«  =  --  28.14°  :' 

Derivatives  :  Oxime,  C10H18NOH.     Thick  oil. 

Alcohol  .........  p  =  20,     rf20  =  0.8250,     [or]£  -    -  4.85  4 

.........  ^^20,     ^?   —0.8199,     [or]^  =    ~  9-21  a 

Hydrochloride,  C10H16NOH.HC1.     Melting-point,  95° 


Alcohol  ........  p  =  10,     </?  =  0.8170,     [a]*,  =    -  24.48°  « 

Dibrommenthone,  C,0H16Br.,O.     Melting-point,  79°  to  80° 
Tetrachloride  of  carbon  .....  p  =  3.05,     [cr]/?  ==  4-  199.4°  T 

/-MENTHONE.     Liquid  ;  boiling-point  206.3°  5  2O7°- 

</•*  =  0.8972,       [«]/?  =  +  17.02°  (calculated  from  [or]y  =  +  21.  i6) 
rf12  =  0.8960,     [cr]«  =    -  28.18°  9 

^  =  0.8934,    [«K=  -  27.67°  10 

Derivatives-.   Oxime.     Crystals;  melting-point,  58°. 
Alcohol  ....  p  =  20,     d*>  =  0.8220,     [a]^  =  -  40-  7  to  -  42 
"      ..../  =  io,     ^  =  0.7998,     M^—  -42.51 

1  Ztschr.  phys.  Chem.,  12,  727. 
Wallach  :  Ann.  Chem.  (L,iebig),  278,  306. 
Beckmann  :  /did.,  250,  338. 
Beckmann  :  Loc.  cit. 

Negoworoff  :  Ber.  d.  chem.  Ges.,  25,  620. 
Beckmann:  I.oc.  cit. 

Beckmann,  Eickelberg  :  Ber.  d.  chem.  Ges.,  29,  41*. 
Atkinson,  Yoshida  :  J.  Chem.  Soc.,  41,  50. 
Beckmann  :  Loc.  cit. 
Binz  :  Ztschr.  phys.  Chem.,  12,  727. 
40 


° 


626  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Oxime Hydrochloride.    Crystals  ;  melting-point,  1 18°  to  119°. 
Alcohol p  —  10,     dM  —  0.8175,     [or]*°       —  61.16°  ! 

Isooxime.    Melting-point,  119°  to  120°  ;  boiling-point,  295°. 

Alcohol p  =  24,     d'21  ac  0.827,      Mp  —    ~  52.25°  - 

TANACETONE  (Thujone?) ,  C,0H16O.  In  the  oil  of  Tanacetum 
vulgare  and  other  oils.  Liquid  ;  boiling-point,  84.5°  (13  mm.). 
dw  =  0.9126,  «/>  for  2  dm.  =  -f-  38.5,  from  which  [<*]/>  ~-  -f-  21.1°  ! 

PULEGONE    (Puleone),    C10H16O.     From   Mentha  pulegium 
(polei  oil).     Liquid  with  boiling-point,  222°  to  223°. 
</=»  =  0.9293,    j>]*3  =  +  25.35°  4 
dw  =  0.9323,     [>]=«  —  -f  22.89°  '"' 

Derivatives:  Oxime,  C10H19NO.,.  Needles  ;  melting-point, 
'57°. 

Alcohol p  —  10,     d'*°      0.7998,     [<r]=';       —  83.44°" 

Oxime  Hydrochloride,  C10H19NO2.HC1.  Crystals;  melting- 
point,  117° to  118°. 

Alcohol p       10,     d™  =  0.8268,     [a]^        -  32.43°  t; 

Pulegone  Bromide,  C10H17OBr.  Crystals  ;  melting-point, 
40.5°. 

Alcohol p       20,     d'M       0.8555,     E^]/jn        —  33-88°  T 

Oxime,  C10H18NOH.  From  pulegone  bromide.  Crystals; 
melting-point,  84°  to  85°. 

Alcohol p  —  20,    d'M  =  0.8277,     [<^]^  =   —  34-53c 

"     /  =  io,      "    -0.8114,  -35-15 

^-CARVONE    (formerly   known   as    carvol),     C10HUO.       In 
cumin  and  dill  oils.     Liquid  ;  boiling-point,  224°. 
d1**  =-.=  0.960,     [a]^-s  ==  4.  60.6°  " 
d™    -----0.959,     [or]-    -=  +  62.2c 

Beckmann  :  I^oc.  cit. 

Binz  :  Ann.  Chem.  (I^iebig),  377,  157. 

Semmler:  Ber.  d.  chem.  Ges.,  35,  3344. 

Barbier:  Compt.  rend.,  114,  126. 

Beckmann,  Pleissner:  Ann.  Chem.   (Mebig),  263,  4. 

Beckmann,  Pleissner. 

Beckmann,  Pleissner  :  Loc.  ctt.,  22. 

Beckmann,  Pleissner :  Loc .  cit.,  27. 

Fliickiger :  Ber.  d.  chem.  Ges.,  17,  Kef.  ;vss. 

Beyer:  Ibid.,  16,  Ref.  1387. 


,0    10 


CAMPHORS   AND   TERPENES  627 

Derivatives  :  Hydrogen  Sulphide  Carvone,  C10H14O.H,S.  Crys- 
tals ;  melting-point,  187°. 

Chloroform c  ---=  10,      [<r]~  ss  +  5.5°  > 

Oxime.     See  under  derivatives  of  /-limonene. 

/-CARVONE.     In  curled  mint   and  kuromoji  oils.     Liquid; 
boiling-point,  223  to  224°. 

d*>  =  0.959,    [or]»  =    -  62.46°  * 

Derivatives :  Hydrogen  Sulphide  Carvone.  Crystals  ;  melting- 
point,  187°. 

Chloroform c  —  JO,     [<*]£'  =   —  5-5°  1 

Oxime.     See  under  derivatives  of  ^/-limonene. 


,  C13H20O.     The  odoriferous  principle  of  the  violet. 
Liquid  ;  boiling-point  144°  (16  mm.). 

d*  =  0.939,     [a]/,  ==  about  -f  42.6°  * 

C.    CAMPHAN  GROUP 

i.  Hydrocarbons 

</-CAMPHENE,  C10H16.  Solid  ;  melting-point,  48°  to  49°  ; 
boiling-point,  160°  to  161°  ;3  melting-point,  51.2°  ;  boiling- 
point,  161°  to  163°.  4 

a.  From  oil  of  turpentine  : 

[a]/,  =  -f  17.6,     ([>]./  =  +  22°)  * 

£.  From  camphor  dichloride.  For  the  fused  substance  at 
t  —  99.8°,  d  ~  0.8345,  and  for  t  =  83.5,  aD  =  -f  55.1°  in  a 
i  dm.  tube.6  If  d**  be  calculated  from  the  data  given  below 
for  /-camphene,  we  have  : 

</*•->  =  0.8482,     [a]«3o  =  +  64.84° 

Melting-point,  57°  to  59°. 


1  Beyer. 

2  Tiemann,  Kriiger  :  Her.  d.  chem.  Ges.,  26,  2680. 

*  Wallach  :  Ann.  Chem.  (Uebig).  330,  234. 

*  Kachler:  Ibid.,  197,  96. 

*  Berthelot  :  Jahresber.  d.  Chem.  (1862),  p.  441. 
«  Spitzer:  Ann.  Chem.  (Uebig),  197,  129. 

•"  Montgolfier  :  Compt.  rend..  85,  286. 


628  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

c.  From  bornyl  chloride.     aD  -    -\-  19.94°   f°r  fused  sub- 
stance in  i  dm.  tube  at  85°.     If  we  take  the  specific  gravity 
as  for  1-camphene,  we  have  : 

</-•'     -  0.8168,     [a]8s  —  -}-  24.4°  ' 

d.  From  spike  oil.     Liquid  ;  boiling-point,  156°  to  160°. 

[«]/)        ;   29.10°  - 

Derivatives  :  Hydrochloride,  C10H]6HC1. 
[a]/,  =    -  20.25°  * 

Ethylcamphcne ',  C10H15.C,H5.      Liquid  ;  boiling-point,  197.9° 

to  199.9°. 

d'M  =  0.8709,     t  —  25°,     |>]/>        +  7-2°  ' 

I sobutylcamphene ,  C10H15.C4H9.     Liquid  ;   boiling-point,  228° 

to  229°. 

d-°  -0.8614,    t      21°,     [<r]/> -= -f  7.4°  5 

/-CAMPHENE,  Terecamphene. 

a.  From  /-turpentine  hydrochloride  and  alcoholic  potash. 
Melting-point,  45°  ;  boiling-point,  160°. 

\a\D  =   -50.4°,    (OL-       -63)" 

Melting-point,  45°  to  48°  ;  boiling-point,  156°  to  157°.     For 
the   fused    substance    at     the   temperature   /,   </ ~  0.888 1- 
0.000839  t. 

Alcohol q       62  to  90,      t=  13  to  14°,     [<r]#         —  53-8o  +  0.03081  q 

Thus,  p       20,     !>]/,         -  51.34°  - 

b.  From  citronella  oil.     Liquid  ;  boiling-point,  160°. 

rfi:>      0.864,    [a]/,  =   -  67°  s 

c.  From  kesso  oil.     Liquid;  boiling-point,  159°  to  161°. 

rf15  =  0.871,     \_O\D        -  70.4°  " 

Derivatives:    Hydrochloride,     C10H16.HC1.     Solid;     melting- 
point,  147°. 

Alcohol p  -  10.5,     [a]/,     =  -f  30.25°  10 

1  Kachler  :  Ann.  Chein.  (Iyiebig),  197,  qy. 
Bouchardat :  Compt.  rend.,  117,  1094. 
Bouchardat :  IAC.  cit. 
Spitzer  :  Ann.  Chem.  (I^iebig),  197,  135. 
Spitzer. 

Bcrthelot :  Jahresber.  d.  Chem.  (1862),  p.  457. 
Kiban  :  Ann.  chim.  phys.,  [5],  6,  357. 
Bertram.  Walbaum  :  J.  prakt.  Chem.,  [2],  49,  17. 
Bertram,  Walbaum  :  Loc.  cit. 
Riban  •  Ann.  chim.  phys.,  [5],  6,  360. 


CAMPHORS    AND    TERPEXES  629 

Formate,    C10H16.CH2O.,.     Liquid;    boiling-point,    125°    (40 
mm.). 

d"        1.0276,      [tr]/>  =  ~  10.3°  ' 

Acetate,  C10H16.C,H4O2.     Liquid  ;  boiling-point,  123°  to  127° 

(35  mm.). 

</"  ==  1.002,     [a]/,  =  +  19.45°  - 

n-Camphcne  Phosphonic  Acid,  2C10H15.PO,H2  +  H,O. 
Alcohol  ......    [«•]/>=    -  119°  :! 

/J-  Camphene  Phosphonic  Acid,  C10H,.  .  PO3H.,.      Melting-point, 

170°. 

Ether  .......    [or]/,  =    -  71°  4 


,  ^-Terebenthene,  Australene,  C,,,H16.     Isobtained: 

a.  From   American  oil  of   turpentine   {Pin  us  Australis,  P. 
taeda}.     The  commercial  oil  shows  extremely  variable  rotation 
which  is,  in  many  cases,  due  to  the  presence  of  /-pinene  from  the 
southern  spruce  pine.     For  the  common  oil  not  known  to  con- 
tain the  spruce  product,   there  was  found    [«]  D  —  ••  -\-  9°  to 
-f-  29°.     The  rotation5  decreases  regularly  on  fractionation. 

d-"  =  0.9108,     [«]™  =  -f  14.15°  rt 

b.  From  Russian  oil  of  turpentine  (Pinus  sylvestris,  P.  Abies}  . 
The  commercial   oil  shows   [«]/,  -f-  11.5°   to  17°   (and  some- 
times higher). 

For  the  pure  ^/-pinene  there  is  given  : 

Boiling-point  156.5°  to  157.5°-  ••  ^'"     -^0.8631,     \ci\*     =^36.3OT 
"       155-5°  "  I56.50---  d^  —  0.8547,     [«r]^-5  =  +  32.4OK 
"       155-5°  "   I56.50---  d*    -0.8600,     [aj-   =        32.0°^ 
11       161°  .............  [<*]D=  -r  I/-I  -  I9-4010 

156°  (corr.  )  at  753  mm.  d»  —  0.8746,  d*  =  0.8585 

M^8  -^-45.04°  " 
From  cumin  oil,  b.  p.  157°  to  158°  ......   d1  —  0.8404,   [>]/>  =      29.46°  '- 

I^afont:  Ann.  chim.  phys  ,  [6],  15,  149. 

I.afont. 

Marsh,  Gardner:  J.  Chem.  Soc.,  65,  36. 

Marsh,  Gardner. 

Ivong:  J.  Anal.  Appl.  Chem..  7,  99  (1893)  ;  Chem.   Centrbl.,   1893,   i,  835. 

I,andolt  :  Ann.  Chem.  (l,iebig),  189,  315. 

Atterberg  :  Ber.  d.  chein.  Ges.,  10,  1203. 

Flawitzky  :  Ibid.,  n,  1846. 

Flawitzky  :  Ibid.,  ao,  1956. 

Berthelot  :  Ann.  chim.  phys.,  [3],  40,  5. 
11   Flawitzky  :  J.  prakt.  Chem.,  [2],  45,  115. 
''-  Wolpian  :  Pharm.  Ztschr.  fiir  Russia  nd,  3s,   145 


630 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Rimbach1  found  for  the  influence  of  different  solvents  011 
turpentine  oil  having  [«]£  =  =  -f  34.81°: 

Alcohol ?  =  10  to  100,  /  =  2o°,  [»=  34.851 0-39Ir/^ 

<j  —  120.27 

from  this  for  c    -  20,     [>]/>  =  35.63° 
Glac.  acet.  acid. . .  q  —  10  to  100,  /  =  20°,  [<*]/>  =  34.889  -f  0.0017465  q 

+  0.00033528  q1, 
from  this  for  c       20,     [or]/;  =  36.90° 

These  figures  are  given  for  the  rotations  of  the  oil  of  tur- 
pentine in  mixtures  of  alcohol  and  glacial  acetic  acid  : 


Comp.  of  the  mixture. 

Turpentine  oil 
in  100  parts  of 
solution  . 
Per  cent. 

d? 

of  the  sol. 

[«]£ 

of  the  turp. 
oil. 

Glac.  acid. 
Per  cent. 

Alcohol. 
Percent. 

84.8 

15-2 

20.2 

0.9653 

36.790 

70 

30 

20.3 

0-9349 

36.63 

50 

50 

20.  6 

0.8949 

36.44 

30 

70 

20.4 

0.8578 

36.15 

15 

85 

20.4 

0.8298 

35-97 

Derivatives:  Hydrochloride,  C10H1(f.HCl.  Crystals;  melting- 
point,  125°. 

Alcohol p  -   28.7,      d"       0.8496,     [>l£  =  +  30.96° 

"       p=  12.24,     rf1*  =  0.8147,     [«]*       +31.23 

The  specific  rotation  calculated  from  this,  independent  of 
the  solvent,  is : 

[»=  -i  28.79°  '2 

According  to  Wallach  and  Conrady'1  the  hydrochloride  and 
the  hydrobromide  are  inactive. 

Dtbromide,  C,0H)6Br2.     Liquid. 

<?  =  1-5943,     d™  =  1.5725,     [«]»       +  30.5°  4 
dw      1.1243,    [«]/»  -  +  7-04° 5 

According  to  I^ong,6  the  hydrochloride  is  active.  He  gives 
[<*]/>  =  :  +  7.17°  as  the  value  obtained  in  experiments  with 
the  product  from  American  oil  of  turpentine.  When  the 

Ztschr.  phys.  Cheni.,  g,  701. 

Flawitzky:  J.  prakt.  Chem.,  [2],  45,  118. 

Ann.  Chem.  (Uebig).  353,  156. 

Flawitzky  :  IMC .  <  it. 

Wolpian  :  Ijoc  cit. 

J.  Am.  Chem.  Soc.,  ai,  637  (1899). 


CAMPHORS   AND   TERPENES  631 

nature  and  sources  of  the  American  oils  are  considered,  it  is 
evident  that  this  value  cannot  be  constant.  An  explanation  is 
thus  given  for  the  discordant  results  of  different  observers  on 
this  point. 

/- PINENE,  Terebenthene. 

a.  French  oil  of   turpentine  {Pinus  pinaster,    Pinus   mari- 
tima).     The  commercial  oil  shows  [«]/>  =      -  25°  to  43°. 

b.  Venetian   turpentine  oil   {Pinus   larix).     For   the  com- 
mercial oil  [a]D  =      -  4.2°  to  4.8°. 

c.  Templin     oil,    oil  of     pine    cones     {Ptnus  picea,   Pinus 
Pumilio),  [a]y  =      -  8.20.1     d*  =  0.856,  a-yin  i  dm.  tube  = 
85-2,      |>I  -      -  98.8.     Rectified,     ^  =     -  92.5,     [>]y  = 
107. 6°. 2 

d.  In  American  oil  of  turpentine   also,  /-pinene  has  been 
found  by  Long/'  the  specific  rotation  of  which,  was  in  one  case 
found  to  be  \OL\D  -     -  40.79°.     The  /-pinene  in  this  case  was 
distilled  from  fresh  oleo  resin.     It  is  probable  that  much  of  the 
so-called  American  oil  contains  /-pinene.4 

e.  In  Asarum   EuropaeumL.     Boiling-point,    162°  to  165°. 

,=   20°,    [«]„=      -25.lV 

Boiling-point  161° [a]z>=  —  33.8,  (OL        —  42-3°)  6 

"      161° </r  •  0.8629,       ["]£=  —  37-oi07 

"       156° rf10    .          0.8685,        [<*]/>  =  -40.3°  8 

"      155° rfw  =          0.8587,       [ar]£  =  -43-409 

[or]/,  =    -  44-95°  lfl 
[a\D  =    -49-I011 

The  discordant  results  are  probably  explained  by  the  fact 
that  the  rotating  power  of  pinene  is  diminished  b}7  oxidation 
on  standing  in  the  air.  For  example,  Landolt  found,  with  a 
preparation  having  originally  [ai]D  =  "  37  °,  a  rotation  of 

1  Jolly,  Buchner  :  Ann.  Chem.  (I^iebig),  116,  328. 

2  Fliickiger,  Berthelot  :  Jahresber.,  1855,  p.  643. 

3  J.  Anal.  Appl.  Chem.,  7,  99  (1893)  ;  Chem.    Centrbl.,  I,  835  (1893)  ;  J.  Am.  Chem. 
Soc.,  16,  844  (1894). 

4  J.  Am.  Chem.  Soc.,  21,  637. 

'•>  Petersen  :  Inaug.-Diss.  (Breslaui,  Berlin,  1888. 

''  Berthelot:  Ann.  chim.  phys.,  [3],  4o,  5. 

:  I^andolt:  Ann.  Chem.  (Liebig),  189,  311. 

?  Riban  :  Ann.  chim.  phys.,  [5],  6,  15. 

9  Flawitzky  :  Ber.  d.  chem.  Ges..  12,  2357. 

10  Bouchardat,  L,afont  :  Compt.  rend.,  102,  320. 

11  Bouchardat,  I,afout  :  Ann.  chim.  phys..  [6],  16,  242. 


632  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

[a]7,  —    -  35.7°  after  the  same  oil    had  stood  four  weeks  in  a 
flask  with  air.1 

With   increasing  temperature    up  to    150°    the  rotation  of 
turpentine  oil  is  decreased  according  to  the  following  formula  :' 
[<*]/->  =  36.61  -  0.00444  / 

Derivatives:  Hydrochloride.     Crystals;   melting-point,  125°. 
[a]/,  =     -  26.3°  ••' 
[a\D.--    -  30.69°  ' 

Ifvdrobromidc.     Crystals  ;  melting-point,  92°. 
[or]/,        -  24.6°  ••> 
[a]/,  =    -  27.802°  « 

Phthalimide  Compound,    C6H4(CO),N.ClnHi:,.      Rectangular 
plates;  melting-point,  90°  to  100°. 

[>]/>        -35°38/T 

l-Isoterebenthcnc,   C1(IH1(..     Made  by  heating  /-turpentine  oil 
to  300°.     Liquid  ;  boiling-point,  175°.     d~*  =  0.8416. 
[tf]/>  =  -  9-45°,    OL       -  10.87° » 

Boiling-point,  177.5°. 

/      20°,     [a]/,        -  8.38° « 

</-ISOTERPENE,  CIOH16.     From  </-terpineol  by  action  of  acetic 
anhydride.     Boiling-point,  178.3°. 

^"       0.8480,      [or]-         -    57.6°  '«• 

/-ISOTERPENE,  From  /-terpineol.     Boiling-point,  176.7°. 
d™      0.8529,     [a]-;;        -47-5°  u 

Boiling-point,  179.3°. 

d™       0.8486,     [a]-;;  6i.o01- 

Ann.  Chem.  (Uebig),  189,  311. 

Gernez :  Ann.  EC.  norm.,  i,  i. 

Wallach,  Conrady  :  Ann.  Chem.  (I,iel>ig),  253,  156. 
Gazz.  chim.  ital.,  18,  223. 

Wallach,  Conrady  :  IMC.  at. 

Pesci  .  IMC.  ctt. 

Pcsci :  Gazz.  chim.  ital.,  ai,  i  to  4. 

Ki».:iii     Ann.  chim.  phys.,  [5],  6,  2is. 

Barbier  :  Compt.  rend.,  108,  519. 
'"  Flawitzky  :  Ber.  d.  chrin    O«     12. 
11   Kuriloff:  J.  prakt.  Chem.,  [2],  43,  i.ii. 
11  Flawitxky :  Ber.  d.  chem.  C.es..  ia,  2357. 


CAMPHORS    AND    TERPENES  633 

/-FENCHENE,   C10H16.     From    fenchyl  chloride  and  aniline. 
Boiling-point        150°- 154°,  cf^       0.8667. 
[«]*  =  -6.4601 

2.  Alcohols 

rt'- BORNEOL,  Borneo  Camphor,  rf-nr-Camphol,  C,0H17OH. 
From  Dry obcdanops  camphor  a.  Crystals  ;  melting-point,  198°  ; 
boiling-point,  212°.  Gives*/- camphor  on  oxidation.  With  two 
different  preparations  : 

a.  Acetic   ether c  =  15.4,         /  =  20°,     [a]/,        —  38.83°)- 

£.        "  "     />        17.54-    rf1"1       0.8876,     /       20°,         "        =  +  38.45    ( 

Melting-point,  203°. 

Alcohol p  :=:  20,     </*'  :     o.828o,     /  =  2o° ,     [a]/,  37-44°  :! 

Melting-point,  208.4°. 

Alcohol c       15.4.     /       15°  to  10°,     [«]/.>  ---  -  37-3304 

Toluene />       20,     [a-]/,         -    38°  I  ' 

Alcohol />    -  20,         "  37   j 

(On  artificial  borneols,  isocamphols,  and  on  the  influence  of 
different  solvents  on  the  constants  of  rotation,  see  below.) 
Derivatives:  Bornyl  Chloride,  C10H17C1.     Melting-point,  157°. 
Acetic  ether.  ..  c       17.2,     t  =  20°,     [«]/>     -  about  —  23°  r> 

Ethyl  Borneol,  C1(,H1T.OC,H3.     Boiling-point,    205°  to  208°. 
d"  =  0.9490,     [«]/>  =  +  26.3°  ' 

Chloral  Borneol,  CCl3CH(OH)OC10Hr.   Melting-point,  55°  to 
56°. 
Benzene,  c  =  15.07  (\.2  mol.  in  i  liter),  t~  15°  to  16°,  [a]D  =  -j-  30.13°^ 

Bromal  Borneol,  CBr3CH(OH)OC1(,H17.     Crystals  ;  melting- 
point,  105°  to  109°. 
Toluene,  c  =  21.7  C;.,  mol.  in  I  liter),  /  =  15°  to  16°,   [<x]D  =  -j-  52. 4° 9 

Acetate,  CH.CO.OC^H,..     Crystals;  melting-point,  24°. 
Alcohol  ....   c  =  19.6,     /  -  :  15°  to  16°,     [cr]/,  44-97°  "' 

1  Gardner  and  Cockburn  :  ].  Chem.  Soc.,  73,  276. 

-  Kachler  :  Ann.  Chem.  (Iyiebig),  197,  88,  90. 
'•'-  Beckmann  :  /*/</.,  350,  253. 

4  Haller  :  Ann.chim.  phys.,  [6],  37,  394. 

-  Beckraann  :  ].  prakt.  Chem.,  [2],  55,  31. 
''  Kachler:  Ann.  Chem.  (l,iebig),  197,95. 

'  Bouchardat,  L,afont  :  Compt.  rend.,  104,  695. 

-  Haller  :  Ibid.,  1 12,  144. 

'•'  Minguin  :  Ibid.,  116,  890. 
"'  Haller:  Ibid.,  109,  29. 


634  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Benzoate,  C6H.CO.OC10Hn.  Crystals;    melting-point,  25.5°. 

Alcohol  ....  c  =  25.8,    /  =  15°  to  16°,     |»       +  43-92° l 
Neutral  Succinate,  C2H4(COOC10H17)2.     Crystals;   melting- 
point,  83.7°. 

Alcohol £-=39,     /=i5°toi6°,     [«]/>= -f  42.05° » 

Add  Suctinate,  C2H4.COOH.COOC10H17.  Crystals  ;  melt- 
ing-point, 58°. 

Alcohol c  =  25.4,     /       15°  to  16°,     [or]/)  =  -f  35.59°  :! 

Neutral  Phthalate,  C6H4(COOCIOH17)2.  Crystals;  melting- 
point,  101.1°. 

Alcohol  ....   c  =  43-8,     t  -    15°  to  16°,     \a\D       +  79-54°  a 
AcidPhthalate,  C6H4.COOH.COOC10H17.  Crystals  ;  melting- 
point,  164.48°. 

Alcohol  ....  c  =  30.2,     /=i5°toi6°,     (>]/>  =  -f-  s8.38°3 
Carbonate,  CO(OC10H17),.     Melting-point,  220.6°. 

[a]/,  =  -f  14-37°  4 

Borneol  Phenyl  Urethane,  CeH5NH  .  COOC10H17.  Crystals  ; 
Melting-point,  i37-75°- 

Toluene  ....  c  =  5.46,     /  =  15°  to  16°,     [nr]/,  »  +  34.22°  5 

/- BORNEOL,  Valerian  Camphor,  /-tf-Camphol.  From  valerian 
oil,  n'gai,  bang-phien  and  madder  fusel  oil.  Crystals;  melt- 
ing-point, 204°  ;  boiling-point,  210°.  Yields  matricaria 
camphor  on  oxidation. 

Alcohol,  c  =  15.4,     /       15°  to  1 6° 

From  valerian  oil in.  p.  208.8°,     [<*]/>  =-        37-77°  ]  r> 

n'ga'i "    "    209.0,  "  =    -37-77    I 

"     bang-phien "    "    208.0,  —38.20 

"     madder "    <(    208.1,  "=    -37.8     J 

From  valerian  oil,  alcohol,. . .  p  =  20°,  df20  =  0.828°,   [«]^  =   —  37-74°  7 

Toluene f>       20,     [«]/?=    —  38 

Alcohol p       20,          "         —37 

Haller  :  IMC.  fit. 

Haller:  Compt.  rend.,  108,  410. 

Haller. 

Haller:  Compt.  rend.,  105,  230. 

Haller:  Ibid  ,  no,  149. 

Haller:  Ann.  chim.  phys.,  [6],  37,  395. 
7  Recktnann  :  Ann.  Chem.  (I,iebig),  180,  353. 
1  Beckmann  :  J.  ]>rakt.  Chem.,  |z],  55,  31. 


CAMPHORS  AND  TERPENES  635 

On    the    rotation  in    different  solvents,    see   below   under 


Derivatives:   Chloral  BorneoL     Crystals;    melting-point,  55 
to  56°. 

Benzene  .......   c-      15.07,     /  =  15°  to  16°,     [a]/?  =  —  30.13°  > 

Bromal  BorneoL     Crystals  ;  melting-point,   105°  to  109°. 
Toluene  .....   c  ~-  21.7,     /       15°  to  16°,     [«]/>  =    —  52.4°-' 

Acetate.     Crystals;  melting-point,  24°. 

Alcohol  .....   c=  19.6,     /  =  15°  to  1  6°,     \_O\D  =    -  44.02°  8 

Benzoate.     Crystals  ;  melting-point,  25.5°. 

Alcohol  ....   <:  =  25.8,     /  =  15°  to  16°,     [a\D  =    -  44.18°  * 

Neutral  Succinate.     Crystals  ;  melting-point,  83.7°. 
Alcohol  ....   c  •--.  39,     t       15°  to  16°,     [a]/,       -  42.39°  5 

Acid  Succinate.     Crystals  ;  melting-point,  58°. 

Alcohol  .....   c  =  25.4,    t  ==  15°  to  16°,     \CL~\D  =    -  35-94°  4 

Neutral  Phthalate.     Crystals  ;  melting-point,  101  .  i  °  . 
Alcohol  ----   ^  =  43.8,     /=i5°toi6°,     \CL\D  --    -  79-14°  4 

Acid  Phthalate.     Crystals  ;  melting-point,  164.48°. 

Alcohol  ----   c=  30.2,     t  —  15°  to  16°,     [a]D  =  —  58.27°  4 

Carbonate.     Crystals  ;  melting-point,  219.4°. 
\a\D  =    -44-I06 

Borneol  Pheny  I  Ur  ethane.     Crystals  ;  melting-point,  137.25° 

Toluene....  ^  =  5.46,     t  =  15°  to  16°,     [a]/>  =    -  34-79°  " 
The  following  determinations  are  by  L.  Tschugaeff  :  8 

1  Haller:  Compt.  rend.,  112,  143. 
-  Minguin  :  Ibid,  116,  J5go. 
'•'  Haller  :  Ibid.,  109,  29. 
«  Haller  :  Loc.  cit. 
'->  Haller  :  Compt.  rend.,  108,  410.' 
6  Haller  :  Ibid.,  105,  230. 
'  Haller:  Ibid.,  no,  149. 
f  P.er.  d.  chem  Ges.,  31,  1775. 


636 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


/-Borneol  formate i  .0058 

acetate 0.9855 

propionate 0.9717 

w-butyrate 0.961 1 

;/-valerate °-9533 

;/-caprylate !  0.9343 


-  40.46° 

-  44-40° 
42.06° 

39-15° 
37.08° 

-  3L450 


ft- BORNEOL,  Isocamphol,  Isoborneol. 

Montgolfier1  and  Kachler  obtained  mixtures  of  two  borneols 
by  action  of  alcoholic  potash  on  the  camphors,  of  which  one  is 
stable,  the  other  instable.  The  first  rotates  the  plane  of 
polarized  light  in  the  same  direction  as  does  the  camphor  em- 
ployed, the  second  in  the  opposite  direction  from  that  of  the 
camphor,  which  is  reproduced  also  by  oxidation  of  the  mix- 
ture. Haller"  finds  that  the  stable  borneols  which  he  desig- 
nates as  ar-borneols,  are  identical  with  the  natural  borneols, 
while  the  instable  products,  or  /^-borneols,  are  isomeric. 
Further  peculiarites  are  shown  in  the  following  table  : 


Description. 

[«], 

By  oxidation 
there  is  formed. 

a-borneols  ! 

right-rotating  «            37  to  38      ^-Camphor 

( 

left-rotating     a       —  37  to  38 

/-           " 

Active 

-f 

P-borneols    ( 

right-rotating  ft 

4  34               I- 

(isoborneols)  ( 

left-  rotating     ~p 

-34 

d- 

f 

4- 

tt    and    a                 

Inactive  borneols 

^  "  j     ....   r 

_L 

a      "       ^T 

rf- 

a      4<       ft 

/.        « 

Haller  investigated,  further,   the  influence  of  different  sol- 
vents on  at-  and  /f-borneol  and   found  that  the  rotating  power 

1  Ann.  chitn.  phys.,  [5],  14,  13;  Compt.  rend.,  84,  90,  and  89,  101. 

Ann.  Chem.  (I,iebig),  197,  102. 
4  Ann.  chim.  phys.,  [6],  37,  414. 


CAMPHORS  AND  TERPENES 


637 


of  the  latter  is  changed  by  the  solvent,  while  that  of  the  first  is 
not  altered  except  by  methyl  alcohol. 

[a]/)  for  /       13°  to  15°  and  c  =  7.7. 


Solvent. 

Methyl 
alcohol. 

Alcohol. 

'3S3H1 

Isobutyl 
alcohol. 

Acetone. 

Ligroin. 

cr-Borneol  

"  35-93 

-  37-33 

-  37.23 

-  37-23 

-  37-87 

-  -37-12 

0-Borneol  

—  30.00 

-32.90 

—  33-33 

-  33-54 

22.94 

-  22.72 

Solvent. 

Acetic 
ether. 

Benzene. 

Toluene.   1   Xylene. 

^-Methyl  - 
propylben'zene. 

ct-Borneol  

-  37-55 

-  37-66 

-  37.87     -  37-66 

-  37-66 

/T-Borneol  

-  19.18 

-  18.93     -  18.95 

-  18-97 

d-  or  l-hoborneol  : 
Toluene 
Alcohol 


=  20, 
=_  20, 


a]/>  =  q:  19°  V 
l(         ip  33°  j 


Derivatives  :  Chloral  Borneol.   Not  crystalline  ;  melting-point, 


55 


°  to  56° 


Benzene  ----   /  =  15°  to  16°,     C-    15-07,     [<*]/>  ^    —  56.40 


Borneol  Phenyl  Urethane.  Crystals  ;  melting-point,  130.05°. 
Toluene  or  alcohol  .......  t  =  15°  to  16°,  c  5.46,  |>P  =  -56.77°' 

</-FENCHYL  ALCOHOL  (Fenchol),  C10H17OH.  Formed  by 
reduction  of  /-fenchone.  Crystals  ;  melting-point,  40°  to  41°  ; 
boiling-point,  200°. 

Alcohol  ......  p       9.902,     d-1       0.809,     M/J  ="  +  10-36°  4, 

/-FENCHYL  ALCOHOL.  Formed  from  ^-fenchone  by  re- 
duction. White  crystals  ;  melting-point,  40°  to  41°  ;  boiling- 
point,  201°.  d™  -  0.933. 

Alcohol  ......  p       12.91,    d19  =  0.812,     [a]1/?-    -  10.35°  5 

</-CAMPHENOL,  C1(,H,.OH.  Boiling-point,  196°.  By  action 
of  glacial  acetic  acid  on  /-turpentine  oil,  [a~\v  —  --}-  13.9°. 

Beckmann  :  J.  prakt.  Chem.,  [2],  55,  31. 

Haller:  Corapt.  rend.,  115,  143. 

Haller  :  Ibid.,  no,  149. 

Wallach  ;  Ann.  Chem.  (I,iebig),  272,  104. 

Wallach  :  Ibid..  263,  145. 


638 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


/-CAMPHENOL.      Boiling-point  about  205 
the  ^-compound,  [ai]D  =      -  46.  9°.  ' 


Formed  with 


ISOCAMPHENOL,  C10H17OH.  Obtained  from  French  oil  of 
turpentine  by  heating  with  benzoic  acid.  Melting-point,  47°  ; 
boiling-point,  198°  to  199°.  M/>  =;  +  10.4.' 

</-PiNOL  HYDRATE,  ^-Sobrerol,  CIOH16(OH),.     From  ^-tur- 
pentine  oil.     Monosymmetric   crystals;    melting-point,   150°. 
Alcohol  .......    ......   c  =  5,     [<X~\D  =  -f  150° 

/-PiNOL  HYDRATE,  /-Sobrerol.  From  /-turpentine  oil. 
Monosymmetric  crystals  ;  melting-point,  150°. 

Alcohol  ............   £~5,     O]/)         -  150°  3 

3.  Amines 

</-  BORNYL  AMINE,  CIOH17NH2.  Melting-point,  158°  to  160°  ; 
boiling-point,  199°  to  200°. 

Alcohol  .........  p     -  12.5,     [a]/,  =    -  18.6°  4 

Forster'  has  recently  described  the  preparation  of  two  bornyl 
amines.  One  is  left-rotating  and  corresponds  to  the  base  of 
Leuckart  and  Bach,  above.  This  he  designates  as  neobornyl 
amine.  The  other  he  calls  bornyl  amine  and  is  right-rotating. 
The  following  data  are  given  for  the  derivatives  of  the  latter  : 


benzene. 


Base     C,«H,  NH  . 

_|_      Af     C° 

-   A6  2° 

_1_   57   T° 

Al  ethyl  bornyl  Htiiinc 

i     40O 
—  oft  8° 

_L   »T  00 

TO/'1 
1       Qr    Q0 

Ethyl  bornyl  ainiiie  

°-9°75  (.a   ) 
08047  (  20°  ^ 

T  y°-0 

I         Ql     O0 

+     7C     ,4° 

r  95-9 

+   QO  7° 

w-Propyl  bornyl  amine  •  >  «  • 

o  ROTQ  (\9P\ 

T  93-  ° 

1        QQ   00 

4-   72  O° 

5r*»o 

1       Q7    T0 

tso-Propyl  bornyl  aminie-  •  •  • 
Butyl  bornyl  amine  

0.0919  ^10  ; 
o.886l  (14°) 
o  8002  (  iz°\ 

Oy.O 
+    84.00 

1       QT    70 

+  63.3° 

-i   6  A  8° 

+    8l.I° 

4-  80  7° 

Dimethyl  bornyl  amine  

u.oyw*   \  1O    ) 

01.  / 
+   62.5°' 

+  48.70 
4-  V)  ^° 

+  59-6° 
-f  62  6° 

Kormyl  bornyl  amine  

A?    T° 

1      JU'O 

42.1 
A2  0° 

Benzoyl  bornyl  amine  

42.9 
3T   8° 

1  Bouchardat,  Lafont  :  Ann.  chin,  phys.,  [6],  9,  529. 
»  Bouchardat,  Lafont  :  Compt.  rend.,  113,553. 

Armstrong.  Pope  :  J.  Chem.  Soc.,  59,  315. 
4  I,euckart,  Bach  :  Ber.  d.  chem.  Ges.,  ao,  104. 

J.  Chem.  Soc.,  73,  386  ;  73,  934,  "49- 


CAMPHORS   AND   TER  PENES  639 

Numerical  values  for  other  compounds  are  also  given. 

</-FENCHYL  AMIXE,  C,,,H17NH,.  From  /-fenchone.  Right- 
rotating. 

Derivatives  :  Benzylidene  Compound,  ClftH17N  :  CHC6H5. 
Crystals;  melting-point,  42°. 

Methyl   alcohol  ----  p       2.63,     d™       0.796,      [«]£--=    -  62.1°  l 

/-FENCHYL  AMINE.  From  d-  fenchone  oxime.  Liquid  ; 
boiling-point,  195°.  d"  =  0.9095. 

Alcohol  .....  p  =  14.93,     d*  =  0.816,     [a-]*  =     -  24.63°  - 
Without   solvent  ........  rf9-"'  =    0.920,     [a]*?  =    -  24.89°  3 

Derivatives  :  Formyl  Compound,  C10H1TNH.COH.  Crystals  ; 
melting-point,  114°.  Shows  birotation  which  disappears  in 
twelve  hours. 


°  * 


Chloroform  ...  fi=  3.99,     dn       1.466,     [a]»        -  36.95 

•  •  •  p  --•=  3.78,     d*   =  1.485,     |>]2,  =  -  36.17°  :> 

Acetyl  Compound,    C10H17NH.COCH,.       Crystals;    melting- 
point,  93°  to  94°. 

Chloroform  ........  p       4.59,     d"'  =  1.475,     [<x]3D  ~  —  46.62°  B 

Propiony  I  Compound,  C10H1TXH.COC3H,.    Cn'stals  ;  melting- 
point,  123°. 

Chloroform  ......  p  =  5.0,       d'"    =  1.463,     [a]^  =    —  53.16° 

......  P       3-94,     rfln=  1.466,     \<*\*l=   -52.66° 

Butyryl  Compound,  C1(,H17NH.COC3H..      Crystals  ;  melting- 
point,  77.5°. 

Chloroform  ......  />        1.80,     d4         1.489,     [tr]*,  =    —  53.08°  |  7 

......  ^  =  1-793,    "          1-488,  ~  53-14°  J 

Benzylidene    Compound,    C10H1TN:CHC6H5.  Crystals  ;  melt- 
ing-point, 42°. 

Chloroform  ......  p       5.77,      d*        1.453,     [tr]8/,  =  -f  73-23°  I  T 

......  /  =  5-7i,      "         1-455.  -  73.05°)" 

i  Wallach  :  Ann.  Chem.  (Uebig),  273,  106. 

-  Wallach  :  Ibid.,  263,  142. 

-1  Wallach,  Binz  ;  Ibid.,  276,  318. 

4  Wallach,  Binz;  Ibid.,  276,  318. 

Binz  :  Ztschr.  phys.  Chem.,  12,  726. 
"  Binz  :  IMC.  cit. 
'  Binz. 


640  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

o-Oxybenzylidene  Compound,  C10H17N:CHC6H(OH.  Crystals; 
melting-point,  94°. 

Chloroform p  ^  4.97,     d«        1.471,     [a~\%  =  +  66.59°  j ' 

p       2.49,     &        1.486,     [a\D  =  -f  65.99°  ( 

p-Oxybenzylidene  Compound,  C10H17N:CH.C6H4OH.  Crys- 
tals ;  melting-point,  175°.  Shows  birotation  which  disappears 
in  eighteen  hours. 

Chloroform p  =  1.28,  d™  —  1.4905,  [cr]£  =  -j-  72.00°  l 

o-Methoxybenzylidene  Compound,  C10H1;N  :  CH.C6H4.OCH:1. 
Crystals;  melting-point,  56°. 

Chloroform ....  p  =  5.56,     d«  ==  1.4605,     [or]*,  =±  -f  58.98°  ) l 
....^  =  5.09,     flrio  =  i.46o,       [or]~  =-  + 59.42°  J 

p-Methoxybenzylidene  Compound,  C10H17N:CH.C6H4.OCH,. 
Crystals  ;  melting-point,  54°  to  55°. 

Chloroform....  p  =  4.97,     rf11  =  1.4585,     [a]^1  =  +  78.10°)  ] 
....  p^  4.89,     ^5   =  1.468,       [a]^,  ==  +  78.01°  f 

Aminoterebenthene  Hydrochloride ,  C10H15NH2.HC1. 
\_a-]D  =    -  48.508°  '-' 

4.  Ketones 

^/-CAMPHOR.  Ordinary  camphor,  Japan  or  laurel  camphor, 
C10H]6O.  Melting-point,  178.6°  ;r>  boiling-point,  204°  ;4  209.1° 
(corr.  at  759  mm. )  .5  Camphor  is  active  in  the  fused  condition, 
in  solution,  and  in  vapor  (see  §9)  but  not  in  crystalline  form. 

Landolt6  investigated  the  rotatory  power  of  camphor  in  dif- 
ferent solvents  (see  §53).  The  specific  rotation  of  the  pure 
camphor  calculated  from  the  values  obtained  was  found  to  be, 
in  the  mean,  \_oi]D  -  =  +  55.4°.  The  following  table  exhibits 
the  effect  of  different  solvents  and  the  mean  value  just  given 
is  the  basis  of  the  calculation.  The  data  refer  to  t  =  20°  and 
q  —  40  to  90. 

1  Binz. 

-  Pesci :  Gazz.  chim.  ital.,  18,  219;  Ber.  d.cheni.  Ges.,  22,  Kef.  108. 

:t  Haller :  Compt.  rend.,  105,  229. 

4  I^andolt. 

5  Forster:  Ber.  d.  chem.  Ges.,  23,  2981. 
Ann.Chem.  (Iyiebig),  189,  333. 


CAMPHORS    AND    TERPEXES  64! 


Solvent. 


O]/>for 


Benzene 55.40  —  0.1664?  -(-42.3 

Ethyl  alcohol 55-4°  —  0.1780  q  0.00037  ?2             43.5 

Dimethylaniline 55.40  —  0. 1428  q  44.0 

Acetic  acid 55.40  -  o.  1360  q  44.5 

Methyl  alcohol 55.40  —  0. 1630  q  -f-  0.00066  q1  46.6 

Monochloracetic  ether 55-4°       0.0620  q  50.4 

Acetic    ether 55.40  —  0.0480?  51.6 


We  have  also  the  following  additional  observations  : 

Ethyl  alcohol c  —  7  to  50,     t  =  20°,  [a]D  =  41.982  -f  0.11824  c  l 

/>  =  2o,     /  =  20°,  d-"  =  0.8255,    O]/>=  +  44-22°  - 

q  =  50  to  95,  /  =  22.9°,   [tr]^  =51.945  — 0.0964?' 

Alcohol  of  80  vol.  per  cent.,  c     -    2  6  10     ^  * 

\oi\n  —  40.9     39-25 
Chloroform ^  =  5.     [or]z>  =  44.2 

Acetic  ether- .  q  =  48  to  90,  t=  20°,   \_a\D  - 

56.543  —  0.09065  q  +  0.0004005  g2  5 

Benzene q  =  47  to  90,  /  =  20°,   [a]/>  == 

55.99,  —  0.1847  ?  -f  0.00026902  ?-  « 

75  per  cent,  acetic  ether  -f-  25  per  cent,  benzene  : 

p  =  20,       d**  =  0.8907,     /  =  20°,     [<r]/>=  —  50.12° 

50.5  per  cent,  acetic  ether    -  49.5  per  cent,  benzene  : 

/  =  20.3,  -cTM  =  0.9016,     ^  =  20°,     [a]/)=  —  48.1° 

25.7  per  cent,  acetic  ether  -f-  74.3  per  cent,  benzene  : 

/>    =  20,       ^  =  0.8979,     ^  =  20°,     [a]/)  =  +  45-8906 

Benzene..  ^^51040,  t  =  20°  [a] />=  39-755  -r  o.i 7254  ^T 
On  the  quantitative  determination  of  camphor  in  solutions 

from  the  angle  of  rotation  observed,  see  §184. 

The  specific  rotation  of  benzene  camphor  solutions  increases 

with  the  temperature,  but  the  values  bear  no  simple  relations 

to  each  other.     Forster*  found  : 

1  I^atulolt  :  Ber.  d.  chem.  Ges.,  21,  191. 
-  Beckmann  :  Ann.  Chem.  (Iyiebig).  250,  352. 
:1  Arndtsen  :  Ann.  chim.  phys.,  [3],  54,  418. 
4  Hesse  :  Ann.  Chem.  (L,iebig),  176,  119. 
"•  Rimbach  :  Ztschr.  phys.  Chem..  9,  698. 
6  Rimbach  :  IJQC.  fit. 
~  Forster  :  Ber.  d.  chem.  Ges..  23,  2981. 
"  IMC.  fif. 
41 


642 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Temperature. 


12'. 


U 


[<z\i)iorc--=--    9.997  39.76    40.20 


16°. 


40.64     41.04 


41-45 


22°. 


41.86 


26°. 


42.23 


42.59 


Difference 

[or]z)for  c  —  19.988 
Difference 


0.44      0.44      0.40     0.41      0.41      0.37      0.36 
42.54    42.88  |  43.22    43.56  |  43.85 
0.34      0.34     0.34     0.29 


On  solutions  of  camphor  in  i  so  valeric  acid  and  caproic  acid, 
see  §56. 

Arndtsen1  studied  the  specific  rotation  of  alcoholic  camphor 
solutions  with  different  lights  and  concentrations  and  found  : 

t  —  22.9°,    q  =  50°  to  95° 


Spectrum  line. 


[or]. 


C 38.549  —  0.0852  q 

D 51.945—0.09647 

74.331  —0.1343  q 
b :       79.348  —  0.1451^ 

F \        99.601  — 0.19127 

c ;       I49-696  —  0.2346  q 

Transformation  Products  of  d-  Camphor. 

yCH.CH:i 
METHYLCAMPHOR,  C8HU<^  |  .      Crystals ;     melting- 

XX) 
point,  37°  to  38°. 

Alcohol c  —  16.6,     [a]/?  ~-- -i- 270.65° '- 

MONOCHLORCAMPHOR,  C10H15C1O. 

tx-Compound.      Prismatic  crystals  ;    melting-point,     92°    to 
92.5°  ;  boiling-point,  244°  to  247°. 

Alcohol [a]y  -4-  90°,     ([a],,  72°  :! 

Alcohol [«]/•  95-8°    from  5  per  cent,  solution.' 

See  the  same  paper  for  other  camphor  derivatives. 

1  Ann.  chim.  phys.,  [3],  34,  418. 

-  Minium  :  Compt.  rend.,  112,  1371. 
1  Cazeneuve  :  Ihid.,  94,  1530. 

*  Lowry  :  J.  Chem.  Soc.,  73,  569. 


CAMPHORS  AND  TERPENES  643 

Derivatives  :     Barium     Sulphonate,     (C10HUOC1  SO3)2Ba  -f 
51/,  H2O.     Crystals. 

Water c  =  2.081,     [a]«°  ~  -f  46.8° 

Sodium    Sulphonate,    CieH14OClSOsNa  +  5H2O.      Crystals. 

Water C=  2.010,     [a]£  =  -j-  64° 

Sulphochloride,    C10HUOC1SO2C1.      Crystals  ;   melting-point, 

123°  to  124°. 

Chloroform c  =  4,  [a]^  =  +  1 10.5° 

Sulphonamide,  C1CHUOC1SO2NH2.     Crystals  ;  melting-point, 
149.5°  to  150.5°. 

Alcohol c^=  5-066,     [a]1/,  =  -f  90.16°  T 

ft-Monochlorcamphor.      Crystals;  melting-point,  100°  ;  boil- 
ing-point, 230°  to  237°. 

[*]/=•+ 5T0.     (M/>  =  +  45-6°)  2 

y-Monochlorcamphor.      Crystals;    melting-point,     124°     to 
125°  ;  boiling-point,   220°. 

\ci\D  =  -f  40°  ;! 

DlCHLORCAMPHOR,  C]0HUC12O. 

a-Compound.     Orthorhombic  prisms;  melting-point,  96°. 
Alcohol  or  chloroform . .    [«]/  =  -f  57.3°,     ( [«]z>  =  +  45-8°) 

fi-Compound.     Mass  of  crystals  ;  melting-point,  77°. 

Chloroform [tr]y  =  -  60.6°,     ([or]0  =  +  48.5°))  * 

Alcohol "    =  =  +  57-4°,     (      "    :  =  4-45-9°)i 

TRICHLORCAMPHOR,    C10H13C13O.     Crystals;  melting-point, 


54° 


Alcohol  .....  />--=4-57,     My=-f64°,        (M/>=  +  SL  2°)5 
MONOBROMCAMPHOR,  C10H15BrO. 

ct-Compound.      Monoclinic  prisms  ;  melting-point,  76°. 
Alcohol  .......    \a\D  —  -|-  139.°°  6 


=+  127.7 


Kipping,  Pope  :  J.  Chein.  Soc.,  63,  593- 
Cazeneuve  :  Compt.  rend.,  94,  1530. 
Cazeneuve  :  Ibid.,  io9,  229. 
Cazeneuve  :  Bull.  soc.  chim.,  [2],  37,  454  ;  38, 
Cazeneuve:  Corapt.  rend.,  99,  609. 
Montgolfier  :  Ann.  chim.  phys.,  [5],  14,  no. 
Marsh,  Cousins  :  J.  Chem.  Soc.,  59,  969. 
Haller;  Compt.  rend.,  104,  66. 


644  CONSTANTS   OF    ROTATION    OK    ACTIVE    BODIES 

Derivatives-.    Sulphonic  Arid,    C10H,.BrOSO3H.      Crystals; 
melting-point,   195°  to  196°. 

Water  .........   c  =  2.577,     [a]}}     -  +  88.27° 

Potassium  Sulphonate,  C10HuBrOSO;sK  +  i'/2H2O.     Crystals. 

Water  .........  r  —  4.921,     [a]™  —  —  71.44°  (hydrated) 

=  -f-  76.96°  (anhydrous) 

Sodium    Sulphonate,    C10H14BrOSO:tNa  -f  5H..O.     Crystals. 

Water  ........  c  •-=  4.130,     [«]»,  ==  -f  63.  i°  (hydrated)     )  l 

"  =  4-  80.2°  (anhydrous)  ( 
Water  ........   c  =  4.305  ^  anhydrous),     [<r]  js        —  88.53°  * 

Ammoniun  Sulphonate,  C10HuBrOSO3NH4.     Crystals. 
Water  .........   c  =  4.600,     [a]^  =  -f  84.78°  :! 

"       .........  r:-  4.570,     [«]g==-f  87°* 

Barium  Sulphonate,  (C10HuBrOSO3),Ba  +  51/,,  H2O.   Crystals. 

Water  .........  c  =  5.893,     M9/,  =  +  64.23°  (hydrated)     )  3 

"   =         72.5°    (anhydrous)  j 

Magnesium  Sulphonate,  (C10H14BrOSOJ,Mg.     Crystals. 
Water  .........   ^-=4-758,     [«]u     :    :    27.9°  4 


Sulphochloride,  C,0HMBrOSO,Cl.      Crystals  ;   melting-point, 
136°  to  137°. 

Chloroform  .....   c    -  5.487,     [<r]^  •=  -f    131°  :t 


Sulphonamidc,  C10H14BrOSO.(NH.(.     Crystals  ;  melting-point, 

145°. 

Alcohol c  =  4.596,     [<*]^--~;    112.4°  3 

fi-Monobromcamphor.     White  powder  ;    melting-point,    61°; 
boiling-point,  130°  (lomm.). 

Alcohol c       8.497,     [<r]/>  —    :    29.4°  5 

Derivatives  :  Sodium  Sulphonate,  C10H14BrOSOHNa  -f  2H,O. 
Water c       3.422  (anhydrous),     [<r]^         ;    12.2° 

1   Kipping,  Pope  :  J.  Chein.  Sf>c.,  63,  586. 
"  Marsh,  Cousins  :  IMC.  fit. 
Kipping  I'ope. 

4   Mar-.li.  Cousins. 

•  Marsh,  Cousins:  J.  Chtm.  Soc..  57,  .xjs. 


CAMPHORS    AND    TERPEXES  645 

Ammonium  Sulphonate,  CH1HHBrOSO3NH4. 
Water  .........    [a]/>        —  82°  l 

y-Monobromcamphor.   Crystals  ;  melting-point,  144°  to  145°. 
Alcohol  ............   £-"5-5,     [>]/>        +  40°  * 

MONOIODOCAMPHOR,  C1(IH15IO.     Prisms  ;  melting-point,  43° 

to  44°. 

[a~\D  =  -f  160.42°  3 

CHLORBROMCAMPHOR,  C10H14ClBrO. 
a-Compound.     Prisms;  melting-point,  98°. 

Chloroform  ............  \oi\j  •  =  -f  78°,     (  [»  —  -f  62.4°)* 

fi-Conipound.     Crystals  ;  melting-point,  51.5°. 

[«]y     +51°,    ([«]/>  -  4-40.8°)  * 

For  determinations  on  the  halogen  derivatives  of  camphor, 
see  Marsh  and  Gardner.6 

XlTROCAMPHOR,   C10H,5NO,O. 

a-  Compound.      Monoclinic  prisms  ;   melting-point,    100°  to 
101°. 

Alcohol  .....  p         3.33,  [a],                7.5,  [ar]^  =  —      6.oc 

Benzene  ----  p.-    0.5,  -140,  -112.6 

Chloroform.  ./=    0.676,  —140,  —112.6 

p=    5.206,  -  102,  -    96.5 

p=  19.978,  "   =-    98,  ••    =       -    78.8 

For  a  lengthy  study  of  nitrocamphor  and  derivatives,   see 
Lowry.8 

Derivatives  :  Sodium  Compound,  NaC,0HuNO2O. 

Water  .......    [or]  /       -f  289,     (\a\D  =  -f  232.5°) 

Zinc  Compound,  Zn(C10HuNO2O)2H2O. 

Alcohol  ......    [a:],--        -275°,     ([or],,  =  +  221.2°) 

Quinine  Compound,  C,0H24N2O2(C10HUNO2O)2H2O. 


1   Marsh,  Cousins  :  J.  Chem.  Soc.,  59,  976. 

-  Cazeneuve  :  Compt.  rend..  109,  439- 
;  Halle  :  Dissertation,  Xancy,   1879. 

4  Cazeneuve:  Bull.  soc.  chim.,  [2],  44,  116. 

•"•  Cazeneuve  :  Ibid..  [2].  44,  120. 

"  Chem.  News,  74,  279. 

'  Cazeneuve:  Compt.  rend..  103,  275  :  104,  1522. 

-  J.  Chem.  Soc.,  73,  986  and  75,  216. 

-'  Cazeneuve  :  Bull.  soc.  chim.,  49,  92. 


646  CONSTANTS   OF    ROTATION   OF   ACTIVE    BODIES 

P-Compound.     Microscopic  plates ;  melting-point,  83°  to  84°. 

Alcohol /-=3-33,     OL  =  -t-    7-5,     (I 

Benzene p  _-  3.33,  -  75,        ( 


Alcohol /^3-33,     [<b=+    7-5,     ([<*]*>=  +    6.O0)")1 

11    --60.3°)] 


OT-CHLORNITROCAMPHOR,  C10H14NO2OC1.  Prismatic  needles; 
melting-point,  95°. 

Alcohol  ......    [«]y=   -6.3°,     ([a]/,  -  5°)' 

BROMNITROCAMPHOR,    C10H14NO2OBr.  Prisms;    melting- 


point,  104    to  105. 

Alcohol  ......  c=i,     L«L-   -27°,     ([«]/>-    -  21.  7°)3 

CAMPHONITROPHENOL,  C10HUNO2.OH.     Crystals  ;  melting- 
point,  220°,  with  decomposition. 

Alcohol    ..........  c^i.S,     [«]/>        r  10°  4 

^/y  Derivative,   C10H14NO2O.C2H;tO.     Crystals  :  melting- 
point,  115°,  with  decomposition. 

Alcohol  ............  c  =  2,     [«]/,  =  +  4.25°  5 

NITROSOCAMPHOR,  C10H15(NO)O.     Crystals  ;  melting-point, 
about  1  80°,  with  decomposition. 

Ben/ene  .........   c  ==  0.81  ,     \_O\D  =  +  195°  6 

CAMPHORSULPHOCHLORIDE,    C10H15OSO2C1.       Tetrahedra  ; 
melting-point,  137.5°. 

Chloroform  .......   £  =  5-349,     *  =  14°,     [<*]/>  =  +  128.7° 

CAMPHORSULPHONAMIDE,  C10H15OSO2NH2.     Crystals  ;  melt- 
ing-point, 136°  to  137°. 

Alcohol  ..........  c  —  2.252,    t  =  13°,     [a]/,  =  +  93.6°  ' 

CYANCAMPHOR,  C10H15OCN.     Crystals;  melting-point,  127° 
to  128°. 

Toluene  ......    [a]/?  =  -f-  44.68°  8 


1  Cazeneuve  :  Bull.  soc.  chim.,  47,  922  ;  Compt.  rend.,  104,  1522. 
8  Cazeneuve  :  Compt.  rend.,  96,  589. 

•  Caz«neuve  :   Bull.  soc.  chim.,  43,  69. 
«  Cazeneuve  :  Compt.  rend.,  108,  302. 

•  Cazeneuve  :  I^oc.  cit. 

'  Cazeneuve  :  Compt.  rend.,  108,  857. 

•  Kipping.  Pope  :  J.  Chem.  Soc.,  63,  564- 

•  Haller  :  Dissertation,  Nancy  1879. 

•  Haller  :  Compt.  rend.,  115,  98. 


CAMPHORS  AND  TERPENES  647 

Derivatives:   ^f ethyl  Compound,  C10HUOCN.CH3.     Oil;  boil- 
ing-point, 170°  to  1 80°  (36  mm.). 

Toluene c  —  -\-  9.55,     \_a\D  =  -f-  107.69°  ! 

Haller  and   Minguin"  have  recently   isolated   two  isomeric 
cyanmethylcamphors  with  the  following  characteristics  : 

^-Compound.     Melting-point,  63°  ;  [#],,=:  -j-  150.8°. 

it-Compound.     Oil,  from  which  crystals  with    melting-point 
38°  to  45°  separate.      \a\D  =  =  -f-  90.1°. 

Ethyl  Compound,  C10H14OCN.C2H5.     Oil  ;  boiling-point,  163° 
to  165°  (21  mm.). 

Toluene c=  10.25,     M#  ==  +  120.71° 

Propyl   Compound,    C10HUOCN.C3H7.       Crystals  ;    melting- 
point,  46°  ;  boiling-point,  140°  to  150°  (20  mm.). 
Toluene c  —  10.95,     [a]z>  =  -f  126.16° 

Benzyl    Compound,     C10H14OCN.C7H7.       Crystals;    melting- 
point,  58°  to  59°. 

Toluene c  =  13.35.     M/>  = -f-    93-62° 

o-Nitrobenzyl    Compound,    C10H14OCN.C7H6NO2.      Needles; 
melting-point,   104°  to  105°. 

Toluene £=15.6,       \a\D  =  +    68.37°  l 

CAMPHOR  PINACONE,  C20H34O2.     Melting-point,  157°  to  158°. 

Benzene p  =  23,         d™  =  0.9089,     [<*]^  =  —  27.03° 

"      p—ii.  62,      "  =  0.8949,  -26.13° 

Derivatives:  Chlor  Pinaconan,  C20H31C1.    Melting-point,  75°. 

Benzene p  =  25.47,    a?;8  =  0.9105,     [«]^8  =  -f  44-17°  j4 

"      p  —  74.08,       "=0.9436,  -4-46.50° 

a- Methyl  Ether,  C20H33O2CH3.      Melting-point,  47°. 

Benzene /  =  14.15,    </*°  =  0.8898,     [«]£=- 78-33° 

^  =  56.26,       "  =  0.9123,  -81.80° 

p-Methyl  Ether,  C20H33O2CH3.     Melting-point,  67°. 
Benzene p  =  21.70,    ^  =  0.8935,     [>]£=    -  i33-5o' 

1  Haller:  Compt.  rend.,  113,  55. 

2  Compt.  rend.,  118,  690. 

3  Beckmann:  Ann.  Chem.  (I^iebig),  293,  i. 
*  Beckmann,  p.  7. 

6  Beckmann,  p.  n. 


648  CONSTANTS  OF  ROTATION  OF  ACTIVK  BODIES 

CAMPHOROXIME,     C10HIH:NOH.       Monosymmetric   prisms; 
melting-point,  115°. 

Alcohol />  -=  20,       d™  =  0.835,     [<*]£  ?=        42.40° 

••     p~  8.3,     "=-.0.812,  -41.38° 

Hydrochloride,  C10Hlt.:NOH.HCl.     Crystals;  melting-point, 
162°,  with  decomposition. 

Alcohol />       8.3,     if1"       0.8185,     O]~-  -43-98°  ' 

d-Camphorsulphonate,       C10HlfiX.OH.C10H15O.SO:iH  -f  H2O. 
Long  needles. 

Alcohol c  —  1.7508,     [«]*',  —    ;    4.3°  - 

See  F6rster:t  on  the  esters  of  camphoroxime. 

CAMPHORDICHLORIDE,  C10H)6C12.     Needles  ;  melting-point, 

155°  to  155-5°. 

Acetic  ether c  —  22.34,     [a]  -         —  16°  ' 

CHLORALCAMPHOR,  CIOH16O.CC1SCHO. 

[«]/,  =  +  143 " 

CHLORALHYDRATE  CAMPHOR,  C10H](iO.CCl,CHOH,O.  Thick 
liquid. 

d-~-  1.2512,     [a]/,  ==    :- 33-45° 

CHLORALALCOHOLATE        CAMPHOR,        C10H1(.O.CC1,CHO. 
C,H,OH. 

d  =1.1777,     [«]/>  =  +  36.9°  (i 

BENZYLCAMPHOR  BROMIDE,  C17H,,BrO.    Melting-point,  82°. 
[a]/,  =    r  37.7°  ' 

BENZYLCAMPHOR  DIBROMIDE,   CrH.,0Br.,O.     Melting-point, 
92°. 

[a}n  =  -     6i°- 

MONOCAMPHOR  PHENOL,  Ct;H6O.C10Hlf>O.   Liquid  ;  at  —  23°, 
crystals. 

rf°  =  1.0205,    [«]/'   =H   20°  !) 

Beckmann  :  Ann.  Chem.  (I.iebijf),  250,  352. 
Tope:  J.  Chem.  Soc.,  73,  1107. 
J.  Chem.  Soc..  71,  1030. 
Spitzer  :  Her.  d.  chein.  C.t-s..  n,  1819. 
I'a-rhkis.  Ohtrrniayer  :    IMiarm.  Post.,  21,   741. 
Zeidler  :  Wien.  Akad.  Her.,  2  Abth.,  76,  2^. 
llaller,  Mingum  :  Hull.  soc.  chim.,  [3],  15,  988. 
Mailer.  Mini-uni. 

:  Compt.  rend.,  in,  109. 


CAMPHORS    AND    TER  PENES  649 

HEMICAMPHOR  PHENOL,  2C6HeO.C10H,6O.  Liquid  ;  at  —  50°, 
crystals. 

if         1.040,       [a]/>  10.1°  l 

MONOCAMPHOR  RESORCiN,  C6H6O,.  C10H16O.    Crystals  ;  melt- 
ing-point, 29°. 

Alcohol  ......    £=25.1,     [tf]z>-         22.1°  ' 

DICAMPHOR   RESORCIN,   CfiHt.O,.2C1(1H1(.O.      Sirup;  at  o°, 
crystals. 

di:>  =  1.0366,     [»  =  -  25.15°  l 


,  C10H8O.C1(,H16O.     Sirup  ;  at  —  16°, 

crystals. 

</°        1.0327,     [a]/,    =  +  10.1°  l 

/2-NAPHTHOLCAMPHOR,  3C10HSO.  5C10H,6O.     Liquid. 

d°  =  1.0396,     [a]D  =  —  22.1°  ' 

SALICYLIC    ACID    CAMPHOR,    CTH6O;J>.2ClnH1(.O.     Crystals; 
melting-point,  60°. 

Alcohol  ........   c       20.8,     \_oc\n    :  —  27.05°  ] 

CAMPHAXIC  ACID,  C10HUO4. 

{<*]j       -MS01 

CAMPHINIC  ACID,  C9H15COOH.     Tough  mass. 
[a]/,  ==  +  15-75°  :! 

CAMPHOLIC  ACID,  C7H1TCOOH.     Melting-point,  105°. 
[a],       +49°  8" 

ISOCAMPHOLIC  ACID  ETHYL  ESTER,  C,,HJTCOOC.,H5.     Boil- 
ing-point, 228°  to  229°. 

ct"       0.9477,     [a]/,        -21.5°  5 

CAMPHOCARBOXYLIC  ACID,  C1(1H16O3.     Melting-point,  128.7°. 

[a-]D  --.-{-  66.75°  « 


-  Aschan  :  Act.  soc.  scient.  fennice,  21,  Nr.  5,  p. 

3  Montgolfier  :  Ann.  chim.  phys.,  [5],  14,  70. 

4  Montgolfier  :  Loc.  cit. 

•"•  Gaerbet  :  Bull.  soc.  chim..  [3],  13,  769. 
0  Haller  :  Compt.  rend..  105,  229. 


650  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Derivatives  :  Methyl  Ester,  CUHI5O3CHV     Boiling-point,  155° 
to  160°  (15  mm.). 

Alcohol  ..........   c-    21,     [ar]z>  -—  +  61.9°  T 

Methylcamphocarboxylic  Add   Methyl    Ester,     C12H17O3CH3. 
Melting-point,  85°. 

Alcohol  ........  £=11.2,     [a~\D  —  -f  17.25°  2 

Ethyl  Ester,  C12H17O3C2H5.     Melting-point,  60°  to  61°. 
Alcohol  ........  c=  11.9,     [a]/>  ===  -f  13.8°  2 


ACID,     C8H]4COOH.CH2COOH. 
Melting-point,  234°. 

Derivatives  :     Methyl     Compound,     C,H14COOH.  CH  (  CH3)  . 
COOH.     Melting-point,  175°. 

\a\D  =  +  26.31  °3 

Monethyl  Ester,   C8H14COOC2H5.CH2COOH.     Liquid;   boil- 
ing-point, 228°  to  230°. 

[«]/>  -  +  5i.  i04 

Diethyl  Ester,  C8H14COOC2H5.CH2COOC2H5.     Liquid;  boil- 
ing-point, 220°  to  230°  (  1  60  mm.). 

Alcohol  ............   c—  27.0,     [a]z>  ==  -f-  49-6  to  -f  50.6°  5 

Monobenzyl  Ester,  C8H14COOCTH7.CH,COOH.     Oil  ;  boiling- 
point,  250°  to  275°  at  10  mm. 

Alcohol  .........  c—  7.6,     [or]/,  =  -   52.62°  G 

Dibenzyl  Ester,  CbH14COOC7H7.CH2COOC7H7.    Thickliquid  ; 
boiling-point,  260°  to  269°  at  10  mm. 

Alcohol  .........  c  —  9.85,    [»  =    -f  35.5°  7 

Mononitrile    (Cyancampholic    Acid),     C8H14COOH.CH2CN. 
Crystals  ;  melting-point,  164°. 

Alcohol  .........  c  -  19.5,     \_ci\D  =  +  64.61°  8 

Minguin  :  Compt.  rend.,  ua,  1369. 

Minguin. 

Haller  and  Minguin  :  Compt.  rend.,  118,  691. 

Haller,  Minguin  :  Compt.  rend.,  no,  410. 

Haller,  Mins^uin. 

Minguin  :  Compt.  rend.,  na,  1454. 

Minguin. 

Minguin  :  Compt.  rend.,  112,  51. 


CAMPHORS    AND   TERPENES 


651 


Mononitrile,  Ethyl  Ester,  CSHUCOOC2H5.CN.  Rhombic 
crystals;  melting-point,  57°  to  58°. 

Alcohol  .........    c  =  22.3,     [or]/,  =  -j-  57.7°  * 

Mononitrile,  Benzyl  Ester,  CSHUCOOC7H..CN.  Crystals; 
melting-point,  70°  to  71°. 

Toluene  .........   £=^28.5,     [a~\D  =  -j-  42.8°  2 

Mononitrile,  Phenyl  Ester,  C8HUCOOC6H5.CN.  Boiling- 
point,  267°  to  270°  at  40  mm. 

Alcohol  ........  c  =  2j.it     [  a]  D  =  +  26.66°  3 

Mononitrile,  fi-NaphthylEster,  CSHUCOOC10H..CN.  Crystals; 
melting-point,  117°. 

Toluene  .........  £  —  32.1,     [«]/?  =  +  17.1°  4 

Monamide,   C8HUCOOH.CH2CONH2.     Melting-point,    205° 

to  206°. 

Alcohol  ..........   £=9.18,     [a]D  =  —  63.5° 

</-CAMPHORIC  ACID,  C10H16O4.  Formed  by  the  oxidation  of 
ordinary  camphor  by  nitric  acid.  Monoclinic  crystals.  The 
statements  concerning  the  melting-point  vary  between  170° 
and  188°.  Thus,  188°  (Friedel);3  187°,  corr.  (Riban).6 

Hartmann7  has  made  many  observations,  the  results  of  which 
follow  : 


Solvent. 

>], 

for  t  =  20°. 

limits. 

[a]/?  for 
/  =  15- 

Abs. 

alcohol  .  . 

% 

.178 
•352 

-f  O.OII74  p 
—  0.01174  q 

P 

q 

=  17 
=  57 

to 
to 

43 
83 

}- 

47-35 

Acet 

'{ 

50 
5i 

.689 
.524 

—  0.00835  p 
—  0.00835  q 

p 

q 

=    8 
=  84 

to  15.5 
5  to  92 

1  + 

50.8i 

Glac 

.  acetic  acid- 

45 
50 

.921 
•825 

--  0.04904  p    \  p 
-  0.04904  q        q 

=    6 
=  84 

to  16        \ 
to  94       j 

46.66 

Derivatives  :  Salts.  Hartmann  made  the  following  deter- 
minations with  aqueous  solutions  at  t  =  20°.  The  values 
for  p  refer  to  the  anhydrous  salts  : 

i  Haller  :  Compt.  rend.,  109,  68. 
-  Minguin  :  Ibid.,  112,  51. 

Minguin  :  Ibid.,  iia,  101. 

Minguin  :  Ibid.,  112,  102. 

Compt.  rend.,  108,  984. 

Ibid.,  80,  1381. 

Ber.  d.  chem.  Ges.,  ai,  223. 


652 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Salt. 

Mi'. 

limits. 

\ci\D  for 

( 

17-750  4-  0.23257  p 

p  =  13  to  25 

I  4-  20.08 

( 

41.007  —0.23257  q 

q  =  75  to  87 

j 

NX,         "      ..".-j 

14.778  4-  0.21288  / 
36.066  —  0.21288  q 

/=  ii  to  37 
q  =  63  to  89 

j  4-  16.91 

K            "          ..  ^ 

13.081  4-  o.  13994  p 

p  —  19  to  43 

1  4-  14.48 

( 

27.075  —0.13994? 

q  —  57  to  81 

f 

(NH,),-      [ 

16.447  +  o.  14242  p 
30.689  —  0.14242  q 

P       "  to  37 
q        63  to  89 

\  +  17-87 

Mg        "      ....-[ 

17.824  4  o.i  8779  p 
36.653  —  0.18779  <1 

p  —    8  to  16 
q  =  84  to  92 

>  4-  19.70 

c.     -  :...( 

16.457  +  o.i  2286  p 
28.733  —  0.12286? 

P         3  to    6 
q  =  94  to  97 

|  4-  17.69 

Ba          "      ....{ 

10.908  4-  o.i  2980  p 
23.888  —  0.12980? 

p  =  18  to  36 
q  =  64  to  82 

I   4-  12.21 

Observations  by  Thomsen1  agree  very  well  with  these  data. 
He  determined  the  specific  rotation  of  sodium  camphorate 
also,  and  the  effect  of  addition  of  excess  of  sodium  hydroxide 
solution. 

Landolt"  gives  the  following  figures  : 

Water. . .  /  =  20°,  C10H,4O4K2  c  -   4  to  16,     [a]D  =  14.39  +  o-°6  c 

...  /  =  20,  Na,2  c=2to    9,          "  =  16.62  4- 0.06  r 

"     .../-=  20,  "        (NH4)2    c  =  4  to  17,          "  =  16.98  4-  0.13  c 

Esters.  On  the  nomenclature  of  the  camphoric  acid  esters, 
see  Briihl  and  Braunschweig. :! 

al-Methyl  Ester,  ChH14.COOH.COOCH3.    Melting-point,  85° 
to  86°  ;  boiling-point,  193°  (15  mm.). 
[«]/>  =  +  43-  55°  4 

o- Methyl  Ester,  C,HU.COOCH3.COOH.  Melting-point,  75° 
to  76°  ;  boiling-point,  199°  (15  mm.). 


a/,  =  4-  51.52°  • 

Dimethyl  Ester,    C8H14.COOCH,.COOCH:i. 
264°  (738  mm.)  ;  149.5  C11  mm.). 

d™       1,0747,     [a]"---.  +  48.i60(1 

1  J.  prakt.  Chem..  [a],  35,  157. 

'-'  "Optisches  DrehuiiRsvcrinoxen,"  ist.  t-d.,  p.  225. 

1  Ber.  d.  chem.  Cies.,  aj,  1796. 

4  Haller  :  Compt.  rend.,  114,  1516. 

Haller  :  l.m  .  ,  it. 
"   Briihl  :   LOC,  »/. 


Boiling-point, 


CAMPHORS  AND  TERPEXES  653 

d\~        1.075,       Mtf:     -r  48.32°  ' 
[*]/>=  -f  44.4°  J 

al-  Ethyl  Ester,  CSH14.COOH.COOC,HV    Melting-point,  57°; 
boiling-point,  207°  to  208°  (21  mm.)- 

rf"  --=  1.1004,     [«]/>-=  -f  23.9°  '•' 

o-  Ethyl  Ester,  CSHU.COOC,H,.COOH.     Boiling-point,  216° 
to  2  19°  (30  mm.)- 

d"       1.1133,     [or]/>        -39-i8°   * 

al-Methyl-o-ethyl  Ester,  C8HI4.  COOCH:;.  COOCXH5.     Boiling- 
point,  277°  (746  mm.)  ;  169.5°  (33  mm.). 

d™  —  1.0528,     [a]--2  =  -f-  38.43°  5 

o-Methyl-al-ethyl  Ester,  C8H14.COOC2H5.COOCHV     Boiling- 
point,  278°  (747  mm.);  175°  (38mm.). 

d™  =  1.0448,     [<r]~-2  =  -  45.49°  '•• 

Diethyl    Ester,    C,HU.COOC,H5.COOC2H5.      Boiling-point, 
285°  to  286°  (750  mm.)  ;  155°  (12  to  14  mm.). 

d**  =  1.0301,    [«]^-6  =  4-  36-3°9  " 
dn      =  1.0495,      [or]/,    ==  -f  37.7°  T 

Phenylhvdrazide,  CSHU(COO)2:N.NHC6H3.     Melting-point, 
119°.    ' 


Compound:    C2,H34O7.       From   0-methyl    ester   and   phenyl 
cyanate.     Melting-point,  78°  to  79°. 

[«]„        +  49-33°  !1 

Compound:  C.^H^O;.       From   #/-  methyl   ester  and   phenyl 
cyanate.     Melting-point,  62°. 

[a\D  -  -  81.45°  9 

Camphoric  Anhydride,  C10HUO3.     Melting-point,   217°.     Ac- 

1  Walker  :  J.  Chem.  Soc.,  61,  1091. 

2  Haller  :  Loc.  cit. 

Friedel  :  Corapt.  rend.,  n3,  829. 

Friedel  :  Loc.  cit. 

Briihl  :  Ber.  d.  chem.  Ges.,  35,  1799. 

Briihl  :  Loc.  cit. 

Friedel  :  Cotnpt.  rend.,  113,829. 

Haller:  Ibid.,  114,  1516. 

Haller:  Ibid.*  115,  19. 


654  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

cording  to  Haitmann,1  it  is  inactive  in  benzene  or  chloroform 
solution.     Other  authors  have  observed  left  rotation. 

Benzene /*=o-7705>  [«]/>        —7.12°- 

Benzene..' M/>        —  3-7° 3 

Benzene [<*ly  =    —  3.68°)  4 

Chloroform "    =       0.0°   j 

Amide,  C10HUO2.N2H4.     Melting-point,  241°  to  242°. 
Chloroform [<*]/>  =   -  10.6°  :> 

Chloride,  C1()H14O2C12.    Liquid  ;  boiling-point,  140°  (15  mm.). 

[a]z>  =   -3.0  to  -3.6°)  :< 
Benzene "    =     -7.110  — 8.3°  j 

a-AminicAdd,  C8H14(CONH2)COOH.     Melting-point,  176° 

to  177°. 

Alcohol [(*]/>  =  -f-  45° 

fl-AminicAcid,  CHH14(CONH2)COOH.     Melting-point,  180° 

to  181°. 

Alcohol [a]D  =  -f  60° 

Nitrilic  Add,  Cyanolauronic  Add,  CSH14(CN)COOH.     Melt- 
ing-point, 151°  to  152°. 

[a]*  =;  -f  67.5°  6 

Bromcamphoric  Anhydride. 

Chloroform [or]  /   -—21.1° 

Chlorca  mphoric  A  n hydride. 

\oi\j       -  16.3°  ' 
Campholide,  C10H16O2.     Melting-point,  210°  to  212°. 


ISOCAMPHORIC  ACID,  C,0H16O4.     Melting-point,    170°;  boil- 
ing-point, 294°. 

Alcohol [cr]  /,         —  48.09  :t 

Alcohol [a]/j        -  46°  H 

Alcohol [«]/==    -  48.3°  !) 

Bcr.  d.  chera.  Ges.,  ai,  223. 

Moutgolfier  :  Ann.  chim.  phys.,  [5],  14,  86. 

Marsh  :  Chein.  News,  60,  307. 

Aschan  :  Act.  soc.  scient.  fennice,  ai,  Nr.  5,  p.  i. 

(iuareschi  :  Centralbl.,  1887,  p.  1355. 

Hoogewerff,  Dorp:  Rec.  trav.  chim.  Pays- Has.,  14,  252. 

Haller  :  Bull.  soc.  chim..  [3],  13,  984. 

Friedel  :  Compt.  rend.,  108,  980. 

Aachan  :  l.nc.  cit. 


CAMPHORS    AND   TERPEXES  655 

Derivatives:  o-  Ethyl  Ester,   CIOH,.Ot.C,H..      Melting-point, 
195°  to  197°  (18  mm.). 

d  —  1.1159,     [«]/'       —  49-51°  ' 

Diethyl  Ester,  C10H14O/C2H5).,.      Boiling-point,    165°  (2510 
28  mm.). 

d      1.0473,     \.<*\D  -   -48.53°  - 

CHOLECAMPHORIC  ACID  (Choloidanic  acid),  C1(,H,6O4.  From 
cholic  acid  by   action   of    nitric  acid.      Crystals,   which  turn 
brown  at  270°  without  melting. 

Absolute  alcohol  .............   c    -6.42,     [<*]$=  -7-  56.17° 

Glacial  acetic  acid  ............   c       1.44,  57-83° 

The  specific  rotation  in  alcoholic  solution  is  independent  of 
the  concentration.3 

CAMFHORONIC  ACID,  C6Hn(COOH),.     Melting-point,   158° 
to  159°. 

Water  ......  p  =  10,     [a]j»-5  =    -  26.9°,     ([a]^-s  ==    -  23.91°  )4 

CAMPHOLYTIC  ACID,  CSH13COOH.     Oil  ;  boiling-point,  240° 
to  242°. 

d*  =  1.017,     [«]£-   -5°5 

Derivatives'.  Ethyl  Ester.     Oil  ;  boiling-point,   212°  to  213°. 
df  =  0.962,     [a]£  =  -  5.04°  « 

CAMPHOTHETIC  ACID,  C16H28(COOH)r 

Derivatives:  Diethyl  Ester.     Liquid  ;  boiling-point,    135°  to 
140°  (15  mm.). 

df       1.019,     [«]]?  ==  +  30.6°  T 

DlHYDROXYCYANCAMPHOLYTlC         ACID,        CSHUCOOH.CN. 

Melting-point,  109  to  m°. 

Alcohol  .......    [or]/,  =  —  18.20°  " 

DICAMPHOR  :   Melting-point,  165°  to  166°. 

Benzene  .........  p       5,          M^    ;    -28.07° 


1  Friedel  :  Compt.  rend.,  113,  831. 

-  Friedel. 

;  lyatschinoff  :  Ber.  d.  chem.  Ges.,  13,  1052. 
4  Ossian,  Aschan  :  Ibid.,  28,  16. 

Walker  :  J.  Chem.  Soc.,  63,  499. 

Walker  :  Loc.  cit.,  498. 
7  Walker  :  J.  Chem.  Soc.,  63,  504. 

•  Hoogewerff,  Dorp  :  Rec.  trav.  chira.  Pays.-Bas.,  14,  252. 


656  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Dica mpha ndihydropyridazine  :   Melting-point,    155°  10156°. 
Benzene f>  -..--  5,          [or]"  =  4    118.13° 

Dicamphanhexandion  :   Melting-point,  192°  to  193°. 

Benzene p  =  3.5,       [a]g  =  -r  331  ° 

Alcohol p  —  2.9,       [orjg        r  381° 

Dicamphanhexanasine  :   Melting-point,  201°  to  202°. 
Benzene p       5,          [a]*]       -\S*-i° 

Dicamphanhexadienperoxide. 

Benzene p  =;  3.5,       [«]#  =±  4-  296° 

Alcohol p       2.9,       [ a] g     :  -}-  345.  j  j  o 

Camp haucamphoric  Acid.     Melting-point,  224°  to  225°. 
Alcohol p  -.= :  4.75,     [«]»•«  =  4-  93.6° 

ot-Dicamphandiacidanhydride  :    Melting-point,  143°  to  144°. 
Alcohol /-=i.r,       O])j        -  142°  ' 

/-CAMPHOR.       Matricaria  camphor.       Found  in  the  oil  of 
Matricaria   Parthenium,   and  may   be  made  by    oxidation  of 
/-borneol.     Melting-point,  178.6°  ;2  boiling-point,  204°  ;  d^  - 
0.9853.     The  specific  rotation  in  alcoholic  solution  for  red  light 
(A.  =  635),  and/  —  10  was  found  as  \oi\r  =  —  33°  ;  that  is, 
in  agreement  with  the  rotation  of  laurel  camphor.    The  formula 
for    the    specific    rotation    of   the   latter, :!    [or]r  =  45.25° 
0-1369  3  gives  for/  ==  10  (q  =  90),  [>],.  =     +  32,9°. 4 
Alcohol P  =  2o,    d%  —  0.8255,     M£  =   -  44-22°  ' 

Transformation  Products  of  I- Camphor 

/-CAMPHORPINACONE.     Right-rotating. 

Benzene p       23.74,     d™      0.9075,     [a];;  26.52 

/-CAMPHOROXIME.     Melting-point,  115°. 

Alcohol p  :     20,       d™  «=  0.835,     [a-]-;;    _  -f-  42.5 1 

P        8.3,      '2'°^o.8i2,  =  +  41-38 

Hydrochloride,  CIOH,.NOH.HC1.     Melting-point,  162°. 
Alcohol p  =  8.33,     d™  =  0.8185,     [cr]--;        r  42.52 

1  Oddo :  Oazz.  chini.  ital.,  ay,  X,  149. 

-  Haller  :  Compt.  rend.,  105,  229. 

3  Biot  :  Ann.  chini.  phys.,  [3],  36,  301. 

*  Chantard  :  J.  pharm.  Chem.,  [3],  44,  13  ;  Jahresber.,  iS6;,,  p.  555. 
5  Beckmann  :  Ann.  Chem.  (I.iebijf),  250,  253. 

'  Beckmann  :  /hid.,  292,  25. 
7  Beckmann  :  I.n< .  cit. 

•  Beckmann. 


o  i; 


o   - 


CAMPHORS  AND  TERPENES  657 

/-CAMPHANIC  ACID. 

[«l/=  +  701 

/-CAMPHOCARBOXYLIC  ACID.     Melting-point,  128.7°. 
[a]/,  =        66.86°  - 

/-CAMPHORIC    ACID.      Resembles    ^/-camphoric    acid     and 
rotates  as  strongly  to  the  left  as  the  latter  does  to  the  right.3 
Absolute   alcohol [<*]./  —  —  49-5°  * 

l-Bromcamphoric  Acid, 

Chloroform [a]y  =  +  21.6°  * 

/-IsocAMPHORic  ACID.      Resembles   the   left-rotating   iso- 
camphoric  acid  from  ^-camphoric  acid  and  rotates  as  strongly 

to  the  right. 

OL--  +  48.604 

/-CAMPHORONIC  ACID. 

. 


;,     C10H16O.     From    oil    of    fennel.     Crystals; 
melting-point,    5°  to  6°  ;  boiling-point,    192°   to   193°,   d19  - 
0.9465. 

a.  Direct  from  fennel  oil. 

Alcohol p  —  8.333,     d*s     =0.8045,     La3S  =  +  7L97° 

b.  From  fenchyl  alcohol : 

Alcohol p  =  12.93,     d™    =  0.8090,     [«]g  =  ~\-  71.7°°  6 

Derivatives  :   Oxime,  C10H16NOH.     Crystals  ;  melting-point, 
161°. 

Alcohol. . . .  p  =  1. 14,      d19     =  0.793,       [a]»    =  -  +  65.94° 6 
Acetic  ether  p  =  2.72,       rf14'5  =  0.911,       [«]^>s  =  -f  52.61° 
"        "      p  =  2.24,       du     =0.9115,     [a]  £    =  =  -f  52.28 
41      p  —  i. 60,      ff12'5  =  0.9121,     [<r]£*  =  -f  51.62 

1  Aschan  :  Act.  soc.  scient.  fennice,  21,  Nr.  5,  p.  i. 

2  Haller  :  Compt.  rend.,  105,  229. 

3  Chantard  :  Ibid.,   37,  166;  Jahresber.,    1853,  p.  430  ;   Jungfleisch  :  Compt.  rend., 
no,  791. 

4  Aschan  :  Loc.  cit. 

'•>  Ossian,  Aschan  :  Her.  d.  chem.  Ges.,  38,  16. 
0  Wallach  :  Ann.  Chem.  (^iebig),  363,  132. 
"  Binz  :  Ztschr.  phys.  Chem.,  13,  725. 

42 


658  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Oxime  Anhydride,  C10H,.N.  Oil;  boiling-point,  217°  to 
218°;  d™  =  0.898. 

Alcohol /  =  6.8i,     ^-=0.7985,     [a] *       -j    43-31 01 

/-FENCHONE.  From  thuja  oil.  Crystals ;  melting-point, 
5°  ;  boiling-point,  192°  to  194°;  d™  =  0.948. 

Alcohol />       14.36.     d'*       °-8l5i     [«]$  -    -  66.94°  - 

Derivatives :  Oxime.  Resembles  closely  the  ^-fenchone 
oxime,  and  in  equivalent  concentration  rotates  as  strongly  to 
the  left  as  the  latter  does  to  the  right." 


(from  flf-carvone,  \a\D=-.  -f  62°),  C10HlfiO.   Boil- 
ing-point, 210°,  with  decomposition  ;  d  =  0.9567. 

[or],,          •     173-8°  :1 

MATICO  CAMPHOR,  C^H^O.     In  matico  oil  (Piper  angusti- 
folium).     Hexagonal  crystals.      Melting-point,  94°. 

Fused </;<*--=  0.924,     [«]}«•  =    -  28.45°  1  * 

Dissolved  iu  chloroform p  =  10  rfjs         1.557,     [«]$   =  —  28.73    j 

See  further,  ^7 

PATCHOULI  CAMPHOR,  C1SH.2(.O.  In  patchouli  oil  (Pogos- 
temon  Patchouli}.  Hexagonal  prisms;  melting-point,  54°  to 
55°  ;  boiling-point,  206°;  diA  =  1.051.  Fused,  /  above  59°, 
[a]7J=  -  118°. 

Alcohol [<*]#  =    -  124.5  —  0.21  r  r> 

See  further,  §7. 

D.    POLYTERPENES. 
/.   Sesquiierpenes,  C,.H2l. 

CADINENE  (true  sesquiterpene).     Found  in  many   ethereal 
oils.     Liquid;  boiling-point,  274°  to  275°;     dw    =  O.QIS. 
Chlorofonn p=  13.05,     rf9'*    =  1.385,     [a]^s  —    _  98.56° 

nihydrochloride,  C15H,r2HCl.  Rhombohedral-hemihedral 
prisms.  Melting-point,  118°. 

Chlorofonn ft  - -.    7.212,  d9''9  =  1.460,     [a]*?  36.82° 

Wallach  :  I.nc.  cil. 

Wallach  :  Ann.  Chem.  (Uebig),  373,  102. 
Baeycr,  Kriihl  :  Her.  d.  chem.  Ges.,  38,  639. 
H.  Traut*  :  Ztschr.  f.  Kryst.,  33,   47. 
Montgolfier  :  Bull.  soc.  chitn.,  [2],  38,  414. 


CAMPHOR  AND  TERPENES.  659 

Dihydrobromide,  C15H.H.2HBr.   Needles  ;  melting-point,  124°. 
Chloroform  .....  P  —    7.227,  d9^  =  1.490,     [tt]/>3        —36.13° 

Dihydroiodide,  C15HM.2HI.     Needles  ;  melting-point,  105°  to 
106°. 

Chloroform  .....  p  =    5.568,  rf9'5  =  1.507,     [a]fcs  =  -  48°  » 

tf-PARACOTOL.     Is  probably  a  hydrate  of  cadinene,  C15HMO. 
Boiling-point,  220°  to  222°. 

</'••  =  0.9262,    O]/>  =  -  11.87°  a 

HEMP  OIL.      From   Cannabis  sativa.       Boiling-point,    120° 

to  121°  (9  mm.). 

[or]/,  =   -  10.81  °  3 

PATCHOULENE.     From  patchouli  camphor.     Liquid  ;  boiling- 
point,  254°  to  256°. 


2.   Diterpenes, 

/-DiTERPiLEXE.     From  left  turpentine  oil. 

dn  =  0.9446,     [a]/j  =    -  14.25°  5 

j.    Triterpene,  C^H^. 

^-O'-AMYRILENE.       From    «-amyrin.       C^stals  ;    melting- 
point,  134°  to  135°. 

Benzene  .........   c  =  4,     [a]/>  =  -f-  109.48°  6 

Derivatives  :   ct-Amyrin,  C30H49OH.     Fine  needles  ;  melting- 
point,  181°  to  181.5°. 

Benzene  ......   c  =  3.839,     [tf]^  =  -f  9I-59°  ~ 

Oxy-a-amyrin,   C.^H^O.OH  -f  2H,O.       Needles;    melting- 
point,  207°  to  208°. 

Benzene  .....   c  =  1.653  (anhydrous),     [>]^-5  =  +  108.6°  8 

;  Wallach,  Conrady  :  Ann.  Chem.  (Liebig),  252,  150. 

2  Jobst,  Hesse  :  Ibid,  199,  75. 

;  Valente  :  Gaxz.  chim.  ital.,  n,  196. 

4  Montgolfier  :  Bull.  soc.  chim.,  28,  415. 

6  i,afont:  Corapt.  reud.,  106,  140. 

0  Vesterberg,  Backstrom  :  Ber.  d.  chem.  Ges.,  20,  1245. 

•  Vesterberg,  Svensson  :  Ibid.,  23,  3186. 

•  Vesterberg,  Svensson  :  Loc.  cit. 


660  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Brom-a-amyrin,     C^H^Br.OH.       Crystals ;    melting-point, 
177°  to  178°. 

Benzene £^2.590,     O]#3  —  -f  72.8°  l 

a-Amyrin  Acetate,   C:wH4fl.C2HsO2.       Plates;   melting-point, 

221°. 

Benzene c  =  4.074,     [a]^-6=  -f  77-o°  ] 

/-a-AMYRiLENE.     From. the  ^/-compound  and  P2O5.     Pris- 
matic crystals  ;  melting-point,   193°  to  194°. 

Benzene c  =  0.8709,     [«]^  —    —  104.9°'- 


:.     From  y#-amyrin.     Crystals  ;  melting-point, 
175°  to  178°. 

Benzene ^  =  1.515,     [a]D  =  -f  112.19°  I3 

"       c  =  0.8          [<*]/>  --  -f  110.42    / 

Derivatives:    fi-Amyrin,     CS(IH4!).OH.       Crystals;    melting- 
point,  193°  to  194°. 

Benzene £--1.9055,     [a]^  =  -f  99.81°  ' 

11        £=5  [a^  =  +  94.2* 

P-Amyrin  Acetate,  C^H^.C^HjO.,.     Prisms  ;  melting-point, 

236°. 

Benzene r--4.i5r,     [a]1*-?  =  +  78.6°  l 

ft-Amyrin   Palmitate,    C^H^O.,.     In    coca   wax.     Crystals  ; 
melting-point,   75°. 

Benzene c  =  2,     [crpj  =  -f  54.5°  < 


24.  Ethereal  Oils 

The  rotation  of  the  active  ethereal  oils  varies  in  general, 
more  or  less,  according  to  the  part  of  the  plant  from  which 
they  are  obtained  and  the  method  of  preparation  (pressure  or 
distillation).  Besides  this,  oils  of  known  purity,  in  many 
cases,  have  not  been  obtainable  in  quantity  through  a  suffi- 
ciently long  period  to  permit  the  determination  of  certain  data. 

1  Vesterbcrg,  Svensson. 

1  Vesterberg,  Koch  :  Ber.  d.  chem.  Ges.,  34,  3834. 

»  Vesterberg,  Backstrom  :  Ibid.,  ao,  1246. 

«  Hetfte  :  Ann.  Chem.  (lyiebig),  371,  216. 


ETHEREAL   OILS  66 1 

But  for  a  number  of  oils  of  the  aurantium  group,  on  the  other 
hand,  it  has  been  possible  in  the  laboratory  of  Schimmel  & 
Co.,  of  Leipzig,  to  establish,  after  years  of  investigation,  the 
limiting  values  for  the  rotation,  so  that  oils  which  give  results 
outside  these  may,  with  considerable  certainty,  be  looked  upon 
as  adulterated. 

In  what  follows  the  data  furnished  by  the  reports  of  this 
firm  will  be  given  ;  the  rotations,  a^,  stated  are  the  angles  read 
off  directly  in  degrees  and  minutes,  with  a  tube  length  of  100 
mm.  and  sodium  light. 

Oil  of  Berg  am  ot  (Citrus  bergamia}.  d\\  —  0.883  to  0.886, 
not  below  0.881.  aD  =  •  -f  9°  to  -j-  15°,  not  above  -f  20° 
(principal  constituents — limonene,  dipentene,  linalool  about 
38  per  cent.,  linalyl  acetate). 

Oil  of  Lemon  (Citrus  limonum).  d[\  =  0.858  to  0.861. 
a%  —  59°  to  67°,  not  below  59°.  For  observations  made  at 
temperatures  below  20°,  under  the  same  conditions,  9'  must 
be  subtracted  for  each  degree  C,  and  for  observations  made  at 
temperatures  above  20°,  8.2'  must  be  added  for  each  degree. 
This  correction  holds  for  the  interval,  10°  to  30°  C.  The 
rotation  does  not  change  on  long  keeping,  even  under  unfavor- 
able conditions  (principal  constituents — limonene,  citral,  no 
pinene). 

Oil  of  Orange  : 

a.  Sweet  (Citrus  aurantium}.      d\\  =0.848  to  0.852.     oi^  — 
+  96°  to  98°,  not  below  96°.     Temperature  correction  for  10° 
to  30°   C  :   for  each  degree   under  20°,    -  -  14.5'  ;  above  20°, 
-f~  13.2'  (principal  constituents — limonene,  citral). 

b.  Bitter  (Citrus  bigaradia} .     d\\  =  0.848  to  0.852.     a%  = 
-f  92°  to  98°,  not  below  92°  (limouene). 

For  most  of  the  other  oils  the  limits  of  rotation  have  not 
yet  been  established  with  the  same  certainty.  The  data  in 
the  following  list,  which  likewise  have  been  taken  from  the 
Schimmel  reports  up  to  April,  1897,  may,  nevertheless,  be 
found  useful  for  comparison  in  some  cases.  For  each  oil,  the 
first  figures  refer  to  the  specific  gravity  at  15°,  and  the  second 
give  the  mean  rotation  for  the  D  line  in  a  100  mm.  tube,  as 
read  off  directly. 


662  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Andropogon    Oil   (Andropogon  lanigcr}.       0.915    to   0.919, 

-  4°    to   -f-  34°38'.       Andropogon    odoratus,    0.945     to     °-95 

-  22°  to  —  23°  (phellandrene). 

Angelica  Oil  (Archangelica  officinalis}.  a.  Fruit:  0.856  to 
0.89,  -f  11°  to  -f-  12°.  b.  Fresh  plant  :  0.869  to  0.886,  -f-  8° 
to  -f  21°.  c.  Root:  0.855  to  0.905,  -f  25°  to  +  32°  (phel- 
landrene, methylethylacetic  acid). 

Anise  Oil  (Pimpinella  anisum).  0.980  to  0.990.  Slightly 
left-rotating,  aD  to  —  i°5o'  (anethol,  methyl  chavicol,  anis- 
ketone). 

Asafetida  Oil  {Ferula  asafetida}.      0.975   to  0.990.     t*D  = 
—  9°  1 5'    (pinene?   bodies  containing  sulphur,  and  compounds 
(C,.H,S0),,). 

Basilicum  Oil  ( Ocimum  basilicum}.     0.909  to  0-990.     aD  = 

-  22°   to  -f-  16°   (pinene,   cineol,   camphor,    linalool,    methyl 
chavicol). 

Betel  Oil  {Piper  betle}.  Java:  0.958  to  1.04.  (*„  =  •  -f- 
2°53'  (betelphenol,  cadinene,  chavicol). 

Cajiput  Oil  (Melaleuca,  spec.).  0.92  to  0.93  according  to 
province.  ctn  —  -o°io'to — 2°  (cineol,  terpineol,  terpenyl 
acetate). 

Calamus  Oil  (Acorus  calamus}.  Fresh  roots  :  0.960100.970. 
aD  —  20°  to  31°.  Dry  roots:  0.960  to  0.970.  aD  =  13°  to 
21°.  Commercial  oil :  0.962  to  0.970.  <*/,  never  below  +  10°. 

Camphor- Leaf  Oil  (Camphora   officinalis}.      0.932.      «/,  - 
4°52'  (camphor). 

Caraway  Oil  {Carum  carvi).  0.905  to  0.915.  t*J}  -f-  70° 
to  H-  85°  (limonene,  carvone). 

Cardamom  Oil  {Elettaria  cardamom  it ;;/).  Ceylon.  0.895  to 
0.910.  «/,  =  :  -f  12°  to  -f  13°  (terpenine,  dipentene?  ter- 
piueol?). 

Cascarilla  Oil  {Croton  elutcria).   0.890^0.930.    otD  —  -  -(-  5°. 

Cedar- Leaf  Oil  (Jiniipcrus  virginiand).  0.884  to  0.886. 
«/»=  +  59-5°. 

Cedar- Wood  Oil  ( Juniperus  virginiana}.     0.940  to  0.960. 


ETHEREAL   OILS  663 

<*D  -  -  30°  to  —40°  (cedrene,  cedar  camphor).  Oils  of  dif- 
ferent countries  and  unknown  botanical  origin,  0.906  to  0.928. 
«/>  =  -  5°  to  -f  1 8°  6'  (cadinene,  cedar  camphor). 

Celery  Oil  (Apiumgraveolens).  Fresh  leaves  :  0.848  to  0.850. 
aD=:  -f  48°  to  -f  52°.  vSeed  :  0.870  to  0.895.  <*»  =  :  Hh  67° 
to  -f-  79°  (limonene). 

Conifer  Oils  : 

Turpentine  Oil  (Finns  spec.).  0.855  to  0.876.  American 
oil,  right-  and  left-rotating.  French  oil,  left-rotating ;  other 
European  oils  are  right-rotating  (pinene,  dipentene  in  Russian 
and  Swedish  oils,  also  sylvestrene). 

Pine  Needle  Oil  (Pi?ms  silvestris}.  Swedish,  0.872.  txD  = 
io°4o'.  German,  0.884  to  0.886.  CKD=:-\--J°  to  -f  10° 
(pinene,  sylvestrene,  bornyl  acetate,  cadinene).  Scottish, 
0.885  to  0.889.  <*„  -  7°  45'  to  —  19°. 

Pine  Needle  Oil  (Picea  vnlgaris).  0.888.  aD  =  ~  21°  40' 
(pinene,  phellandrene,  dipentene,  bornyl  acetate,  cadinene); 
from  two-year  cones,  0.892.  aD  =  -  2o°i2r. 

Dwarf  Pine  Oil  (Latschenkiefer)  (Finns  pumilio} .  0.865  to 
0.875.  aD  -  —  5°  to  —  9°  (pinene,  phellandrene,  sylves- 
trene, 4  to  7  per  cent,  of  bornyl  acetate,  sesquiterpene). 

Silver  Fir  Oil  (Edeltannen)  (Abies  pectinata).  Needles: 
0.865  to  0.875.  an  -  -  20°  to  —  60°  (pinene,  limonene,  4.5 
to  7  per  cent,  of  bornyl  acetate,  sesquiterpene).  Young  cones, 
0.855  to  0.870.  aD  -  -  60°  to  —  80°  (pinene,  limonene,  0.5 
to  3  percent,  of  ester,  C]0H17OCH3CO). 

Hemlock    Oil    (Abies   canadensis}.   0.907.      otn  -      ~  20°    to 
-  26°  (pinene,  camphene,  bornyl  acetate,  sesquiterpene). 

Fir  Needle  Oil,  Siberian  (Abies  siberica}.  0.91  to  0.92. 
an  =  -  40°  to  —  45°  (bornyl  acetate). 

Coriander  Oil  (Coriandritm  sativnni}.  0.87  to  0.88.  aD  = 
-f  8°  to  -f  13°  (pinene,  linalool). 

Creeping  Thyme  Oil  (  Thymns  serpylliuni) .  0.905  100.930. 
aD  -  -  i°  to  —  11°  (thymol,  carvacrol,  cymol). 

Curled  Mint   Oil  ( Mentha  crispa}.   0.92  to  0.98.      aD  = 
43°  or  lower  (carvone). 


664  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Dill  Oil  (Anethum  graveolens).  German,  Russian,  Rouma- 
nian fruit :  0.895  to  0.915.  <*/,  +  70°  to  +  80°  (limouene, 
carvone).  East  Indian  fruit  :  a»  ==  +  40°. 

Dog  Fennel  Oil  (Eupatorium  focniculaceum}.    0.935.     an  - 
-f  1 7°  50'  (phellandrene). 

Elemi  Oil  ( Canarium  spec. ) .  0.87  to  0.91.  fry,  -  +  45° 
( phellandrene  dipentene ) . 

Eucalyptus  Oil  {Eucalyptus  %  spec.).  0.86  to  0.95.  otn  =  — 
71°  to  -f-  20°  according  to  source  (citronellal,  cineol,  citronel- 
lone,  pinene,  phellandrene,  alcohols,  and  aldehydes  of  the  fatty 
series). 

Fennel  Oil  (Foeniculum  vulgar e  and  varieties) .  0.920  to  0.987. 
<*D  =  :  +  7°  to  -f  22°.  French,  to  -f  48°  (pinene,  phellan- 
drene, dipentene,  limonene,  fenchone,  anethol). 

I-'rankhicense  Oil  (Bosu'ellea,  spec.).     0.875  to 0.885.     aD 
-  11°  35'  (pinene,  phellandrene,  dipentene). 

Galbanum  Oil  (Peucedanumgalbanifluum  and  varieties)  .0.91 
to  0.94.  «ry,  =  -  5°  to  -j-  20°  (pinene,  cadinene). 

Geranium  Oil  {Pelargonium,  spec.).  According  to  origin  : 
0.886  to  0.906.  otn  —  -  7°  to  —  16°  (gerauiol,  citronellol,  and 
1 9  to  33  per  cent,  of  tiglic  acid  esters  of  the  latter). 

Ginger  Oil  (Zingiber  ojficinalc) .     0.875  to  0.885.     an  = 
26°  to  —  44°  (camphene,  phellandrene). 

Gurjon  Balsam  Oil  (Diptcrocarpus,  spec.).  0.92  to  0.93. 
*D  =  -  35°  to  —  106°. 

Hop  Oil  (Humuljis  lupulus}.  0.855  to  0.88.  ctn  =  + 
4°4o'  and  lower  (terpenes,  humulene). 

Juniper  Oil  (Junipcrus  communis}.     0.865  to  0.885.     <*/,  = 
±  o  to  —  18°  (pinene,  cadinene,  juniper  camphor). 

Lavender  Oil  (Lavcndula    irra}.     French:   0.885  to  0.895. 
<*t,  -      -  3°  to  —  9°    (linalool,   linalyl    acetate  30   to  45   per 
cent.,  geraniol,  cineol).     English:  0.885  to  0.900.     a,, 
7°  to  —  10°  (much  cineol,  linalyl  acetate  7  to  10  per  cent.). 

Lime  Oil,  Italian  (Citrus  limetta}.     0.872.      a,,-     58°  15'. 


ETHEREAL   OILS  665 

West  Indian  (  Citrus  mcdica ,  var .  acida ) .    o.  880  to  0.885.    aD  = 
-h  35°  to  -f  40°  (limonene,  citral). 

Mace  Oil  (Myristica  officinalis).  0.91  to  0.93.  ct n  —  -f  10° 
(pinene,  myristicene). 

Mandarin  Oil  (Citrus  madurensis).  0.854  to  0.858.  otn  = 
-f  65°  to  -f-  75°  (citral,  limonene). 

Mastic   Oil    (Pistacia   lentiscus).   0.855   to  0.870.      aD  =  -f 

22°  tO   -f    72°. 

Onion  Oil  (Allium  cepa} .    1.040.      «y,  =      -  5°  (C6H12S,). 

O  range- Floiver  Oil,  sweet  {Citrus  aurantiitm).  0.87  to  0.890. 
aD  =  -f-  16°  to  -f  29°.  Bitter,  Citrus  bigaradia,  0.87  to 
0.885.  aD  =  -j-  5°  to  -f  10°  (limonene,  linalool,  linalyl 
acetate ) . 

Palma  Rosa  Oil  {Andropogon  SchoenantJius}.  0.888  to 
0.896.  aD-  -  i°4o'  to  +  i°45'  (dipentine,  geraniol,  ger- 
anyl  esters). 

Pennyroyal  Oil  (Mentha  pulegium,  Hcdeoma  pulegioides} . 
0.93  to  0.96.  flr/,  =  +  17°  to  -f  23°  (pulegone). 

Peppermint  Oil  ( Mentha  piper ita ) .  German :  o.  902  to  o.  9 1 5. 
<XD  =  —  25°  to  —  32°  English  :  0.900  to  0.910.  aD  = 
22°  to — 31°.  American:  0.910 to 0.920.  acD=  —  25°  to  —  33°. 
Japanese:  0.895  to  0.905.  aD  -  -  26°  to  —  42°  (menthol, 
menthone,  menthol  esters  of  acetic  and  iso valeric  acids,  alde- 
hydes, tefpenes). 

Rosemary  Oil  (Rosmarinus  offidnalis).  Specific  gravity  not 
below  0.900.  aD  =  .  -{-  i°3o'  to  11°  for  French,  and  -f  o°  45' 
to  4°  30'  for  Italian  (pinene,  cineol,  borneol,  camphor). 

Sandalwood  Oil  (Santalum,  spec.).  East  Indian:  0.975  to 
0.980.  an-  -  17°  to  —  20°.  West  Indian:  0.963  to  0.967. 
«/,  about  -f  26°.  Australian:  0.953.  ao  =  5°  20'  (santalol). 

Sassafras  Oil  (Sassafras  officinal is^.     Leaves:  0.872.     aD  = 
-  6°  25'.     Bark:  1.065  to  1.095.     ao  ='-  +  j0  to  -f  4°  (pinene, 
phellandrene,  safrol,  eugenol,  camphor). 

Savin  Oil  ( Juniperus  Sabina).  0.910  to  0.925.  aD  =  -f 
45°  to  -f  60°  (pinene,  cadinenej. 


666  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Spike  Oil  (Lavendula  spica}.  0.905  to  0.915.  ct,y  usually 
to  +  3°,  seldom  to  +  7°  (pinene,  cineol,  linalool,  camphor, 
borneol,  terpineol  (?),  geraniol  (?)). 

Star  Anise  Oil  (Illicium  verum).  0.98  to  0.99.  aD  =  -f- 
o°  40'  to  —  2°  (pinene,  phellandrene,  methyl  chavicol,  anethol). 

Storax  Oil  (^Liquidambar  orientalist.     0.89  to  1.06.     otD  = 

-  15°  (styrol,  cinnamic  acid  esters). 

Sweet  Marjoram  Oil  (Origanum  major  ana).     0.89  to  0.91. 

a/)    =:    4-     I5°    tO    +     18°. 

Tansy   Oil   (Tanacetiim    vulgare) .     Fresh  plant:    0.915  to 
0.930.  Dry  plant:  0.954.     aD  =    -f  30°  to  45°.   English:  #„  = 
about  —  27°  (thujone,  camphor,  borneol). 

Thuja  Oil  (  Thuja  occidentalism .     0.915  to  0.930.     nr/;  = 
6°  to  —  13°  (thujone,  fenchone,  pinene). 

Tarragon  Oil  (Estragon  Oil)  (Artemisia  dracunculus) . 
0.89  to  0.96.  aD  =  -f-  2°  to  -f-  9°  (methyl  chavicol). 

Valerian   Oil  (  Valeriana  officinalis).     0.93  to  0.95.     vtn  = 

-  8°  to  —  15°   (pinene,   camphene,   borneol,    bornyl  esters). 
Ylang-Ylang    Oil    (Anona    odoratissima} .      0.91    to   0.95. 

aD  -     -  20°  to  —  55°  (benzoic  acid  esters,  linalool,  geraniol, 

etc.). 

25.  Resin  Acids 

DEXTROPIMARIC  ACID,  C20H.M,O,. 

Chloroform £=  10.10,     t  =  20°,     [or]/)         f   73-36°  * 

ABIETINIC  ACID,  C19H28O.j. 

[a]/,  *        66.66°  to       67.34°  - 

PODOCARPINIC  ACID,  C17H,,O3. 

Alcohol c       4  to  9,     [a]D        4    I36°}:{ 

lUher c    -.  4  to  7,          "    :  =  -f  130  f 

Salt,  CITHHO3Na  +  8H,O. 

Water C±=    4.6,     [a]/,      -82°^* 

"      ^         6.4,          "         79    | 

"      c       13-8,          "      ^73    I 

86    J 


Alcohol c         9.0 

1  Kimbach  :  Her.  d.  pharm.  Oes.,  (1896),  p.  63. 

2  Mach  :  Monatsh.  Chein.,  15,  627. 

3  Oudemans  :  Ann.  Chem.  (I.iebig),  166,  65. 
*  Oudemans  :  Loc.  cit. 


ALKALOIDS  667 

TURPETHINIC  ACID,  C34HMO18.     Melting-point,  168°. 

[«]/>  =    -  37-49° 
CONVOLVULINIC  ACID.     Melting-point,  175°. 

[a]D  =    -  45.30  > 

26.  Alkaloids 
Alkaloids  of  the  Aconite  Species 

ACONITINE,  C.!3H45NO12.     Rhombic  crystals  ;  melting-point, 
188.5°  (corr.). 

Alcohol p  =  3.726,     [a]^  =  ~f  11.01°  V-' 

£=2.746,     [a]~=+n.io    j 

Formerly  described  as  left-rotating.     See  Jiirgens.3 

Hydrobromide,  C33H45NO12.HBr  -f  21/,H1O.     Crystals. 

Water ^  =  5.183,     [or]«°  =   -3'-3°].4 

Recrystallized /  =  1.95,  —  30.47  / 

Is  ACONITINE  (Napelline),   CjgH^NOj.,.     Crystals;  melting- 
point,  125°  (corr.). 

Alcohol c=  7.86,     [a]g  =  +  4-48° 

Hydrochloride,     C33H45NO12.HC1  +  H2O.       White    needles; 
melting-point,  268°  (corr.). 

Water tf=t,     [or]^  =  —  28.74° 

Hydrobromide,    C33H45NO12.HBr.       Needles;    melting-point, 
282°  (corr.). 

Water <r=l,     [«]^f   -   -  3°-47° 

Hydroiodide,  C33H45NOirHI.     Crystals  ;  melting-point,  242° 

(corr.). 

Water c  =  it     |>];s  =    -  26.94°  3 

PYROACONITINE,  C31H41NO10. 

Water c  =  1.121,     [or]^  =  —  9Q-99° 

Hydrobromide,  C31H41NO10.HBr. 

Water r  =  2.136,     [or]£  -    -46.8° 

PYROACONINE,  Hydrochloride,  C24H37NO9.HC1  +  H2O. 

Water ^  =  1.96,     [or]g  =    -  102.07°  " 

Kromer  :  Z.  Oesterr.  Apothek.-V.,  49,  520. 

Dunstan,  luce  :  J.  Chem.  Soc.,  59,  281. 

Jahrcsb.,  1885,  1722. 

Dunstan,  Ince  :  Loc.  cit. 

Dunstan,  Harrison  :  J.  Chem.  Soc.,  63,  445- 

Dunstan.  Carr  :  Ibid.,  65,  176. 


668  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

ACONINE,    C^H^NO,,.      Amorphous;   melting-point,    132° 
(corr. ).     By  hydrolysis  from  isaconitine. 

Water p       3-534,     rfjs  =  i.oi,     [a]>$   -r  -f  23° 

Hydrochloride,  C,GH41NOn.HCl  -f  2H.,O.     Crystals  ;  melting- 
point,  175.5°  (corr.). 

Water,  />  ^  5.75   (anhydrous),     </js  =  1.015,     [nr]^  =    -  7.71°  ' 
Water,    c  =  2. 398 (anhydrous),     [«])s  -ss    -  7.72°  • 

LYCACONITINE,  C,,7H:UN.,O6  +  2H.2O.     Amorphous  ;  melting- 
point,   111.7°  to  114-8°. 

Alcohol /=  10,     O]^,  =  +  31.5°  3 

ATISINE,     C^H^NO^      (from     Aconitnm     heterophyUum)  : 

Alcohol [or]/)  -     -  19.6°. 

Hydrochloride  (C2,H:nNO.,)HCl,  m.p.  296°      Water,  [a]/,  =  +  18.46°  ^  * 
Hydrobromide      "       "        HBr,     "     273°  =-(-24.3 

Hydroiodide         "       "       HI,        "     2790-28o0  "  -  +  27.4      J 

For  later  observations  on  aconite  alkaloids,  see  Dunstan  and 
Carr,5  and  Dunstan  and  Read/' 


ARGINIXE,  C6HUN4O,.     The  free  base  has  not  been  investi- 
gated. 

Hydrochloride,  CfiHuN4O,.HCl.     Monoclinic  crystals. 
Water c       8,     [a]^  =  +  33. ic 

Nitrate,  C.HuN4OrHNOs  +  V2H,O.     Needles. 

Water c  —  IO,      [o-]^  —  J..  28.75°  ' 

ARIBINE,  C^H^N,  -f  8H,O.     Crystals  ;  melting-point,  229°. 
Inactive/ 

ASPIDOSPERMINE,  C,,H:10N2O2.     Prismatic  crystals  ;  melting- 
point,  205°  to  206°. 

Alcohol  (97  vol.  p.  c.) £=2,     [«]/=--    -100.2°  i9 

Chloroform c  =  2,         "  -    83.6 

Water  -f-    3  mol.  HC1 c  —  2,  -    61.6    I 

"        -f   10      "  "     C=  2,  "  -     62.2     j 

Dunstaii.  I'as.sinore  :  J.  Chem.  Soc.,  61,  400. 
Dunstan,  Harris<jn  :  /.»<-.  til. 

Dragendorff,  Spohn  :  Ber.  d.  chein.  (ies.,  17,  Ref.  378. 
Jowett  :  Chem.  News,  74,  120. 
J.  Chem.  Soc.,  71,  350. 
I  hid.,  77,45- 

Schulze,  Steifcer  :  ztschr.  phys.  Chem.,  n.  43. 
Rieth  :  Iiiaujf .-Diss .,  c.«Jttingeti,  1861. 
-     Ann.  Chem.  (I,iet>ig),  an,  254. 


ALKALOIDS  669 

ASPIDOSPERMATINE,  C22H2(JN2O2.    Wart-like  lumps  ;  melting- 
point,  162°. 

Alcohol    (97  vol.  p.  c.)  ..........  c=2,     [a]^5  •_=    _  72.3°  i 

QUEBRACHINE,    C21H26N2O8.      Prisms  ;  melting-point,    214° 
to  216°  (uncorr.).- 

Alcohol  (97  vol.  p.  c.  )  ----   c  ==  2,     [or]  js  =  —  62.5°  |3 

- 


Chloroform  ..............  <:       2,  =  -f  18.6 

PAYTINE,  C21H,4N,O  -f-  H2O.    Crystals  ;  melting-point,  156°. 
Alcohol  (96(?)  vol.  p.  c.)  .......   <:•-=  0.454,     [«]g  -   -  49-5°  * 

ATROPINE,  C17H,,NO,.   Crystals  ;  melting-point,  1  15°  to  1  16°. 
Absolute  alcohol.  .  c  =  3.22,     [<*]^f  =  —  0.4°  5 
Alcohol  ..........   c  =  6.67,     [a]£  =    -  i  .89°  fi 

According  to  Ladenburg7  and  Gadamer8  atropine  is  optically 
inactive. 

The   Atropinum    naturale    is   a   mixture   of   atropine    and 
hyoscyamine. 

Sulphate,  (C1TH23N03)2H2S04  +  H,O.     Crystals. 

Water  ......   c  —  2  (anhydrous),     [a]^  =   -  8.8°  9 

SCOPOLAMINE,  C]TH.;1NO4  +  H2O.     Melting-point,  59°. 
Absolute  alcohol  ----  p  =  2.65,     [apj  =    -  13.7°  10 

Melting-point,  56°. 

Water  ........    [or]/?  -    -  14.97°  n 

HYOSCYAMINE,  CnH23NO3.     White  needles  ;  melting-point, 
108°  to  109°. 

Absolute  alcohol  .........  c  =  17.2,  [a~\2£  =  —  2i.6oc 

.........   C—  12.4,  -  21.76 

.........   c=    6.2,  "    =  —  21.25 

"        .........  c=    3.1,  "    =  —  20.26 

Alcohol  (50  per  cent)  .....  c=  12.4,  —  20.27 

1  Hesse  :  Loc.  cit.  259. 

•  Hesse  :  Her.  d.  chem.  Ges.,  13,  2308. 

3  Hesse  :  Ann.  Chem.  (I^iebig).  ail,  265. 

4  Hesse  :  Ibid.,  166,  272. 
'->  Hesse  :  Ibid.,  271,  101. 

•  Will,  Bredig  :  Ber.  d.  chera.  Ges.,  ai,  2777. 
7  Ber.  d.  chem.  Ges.,  ai,  3065. 

•  Arch.  Pharm.,  a34,  543. 
0  Hesse  :  I^c.  cit. 

10  Hesse:  Ann.  Chem.  (Liebig),  ayi,  in. 

11  Zuboldt  :  Diss.,  Marburg,  1895. 

12  Will  :  Ber.  d.  chem.  Ges.,  ai,  1717. 


670  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Alcohol c       i  to  12,     [tt]£  -     -  21.016  —  0.0154  c  l 

Absolute  alcohol,  c  =  3.22,     [o-]^  =    -  20.3°  - 

By  action  of  bases,  hyoscyamine  is  converted  into  atropine. 


Sulphate,     (C17H23NO3),H,SO,  +  2H,O.       White     needles; 
melting-point.  201°. 

Water c       2  (anhydrous),     [tfpj        -  28.6°  4 

Water p  =  2.9,     [a]/,  ±=i   -  26.8  to  —  27.3°  5 

Oxalate,  anhydrous. 

Water />  =  1.6,     f»  -    -  24.07°  6 

PSEUDOHYOSCYAMINE,  C17H23NO3.     Yellow  needles  ;  melting- 
point,  133°  to  134°. 

Absolute  alcohol p  -—  5.26,     [>]],=    —  21.15°  7 

HYOSCINE,     C,7H.aNO4(?).      Hard,    transparent,    resin-like 
masses  ;  melting-point,  55°. 

Absolute  alcohol c=  2.65,     [arpj  =    -  13.7°  " 

The  rotation  is  greatly  decreased  by  addition  of  a  small 
amount  of  sodium  hydroxide  solution. 

Hydrobromide,  C1THMNO4.HBr  +  3H,O.     Rhombic  crystals. 
Water c  =  4,     M'J  =     -  22.5°  4 

BEBIRINE,  C,HH.21NO3.     Melting-point,  214°. 

Absolute  alcohol p  =  1.6,     [or] 5"        -  298°  !) 

BERBERINE,  C20H17NO4  +  4H2O.      Crystals  ;  melting-point, 
120°.     Inactive. 

OXYACANTHIN,  ClhH19NO3.    Crystals;  melting-point,  138°  to 
150°  (from  water)  ;  208°  to  214°  (from  alcohol), 
i  vol.  alcohol  (97  vol.  p.c)  -}-  2  vol.  chloroform,    c  =  4,  [<*]$  =  -}-  131.6°  1(( 

Hydrochloride  C1HHJ9NO3.HCI  -f  2H.2O.     Needles. 
Water    c  —  2,     [or]$  —  +  163.6°  4 

1  Hammerschmidt,  Will  and  Bredig  :  Ber.  d.  chem.  Ges.,  21,  2784. 

2  Hesse  :  Ann.  Chem.  (I«iebig),  271,  103. 

Will  and  Bredig  :  Ber.  d.  chem.  Ges.,  21,  2777. 

Hesse  :  IMC.  oil. 

Gadamer  :  Arch.  I'harm.,  234,543. 

Gadamer  :  Luc.  cit. 

Merck  :  Arch.  Pharm..  231,  117. 
*  Hesse:  Ann.  Chem.  (I.iebijo,  271,  no. 
v  Scholtz  :  Ber.  d.  chem.  Ges..  29,  2058. 
10  Hesse  :  Ibid.,  19,  3192. 


•  o  -i 


ALKALOIDS  671 

HYDRASTINE,  C21H.nNOH.  Rhombic  crystals  ;  melting-point, 
132°. 

Chloroform c  =  2.552,     [or]^  —      .    67.8°  V 

Water    -    2  inol.   HC1-.  c  -•-  4.050,  -  127.3 

Chloroform c       3.042,     [<*]/>  =      -    57. 

Methylhydrastine  Hydrochloride ,  C2,H23NO6.HC1.  Crystals; 
melting-point,  241°.  Inactive  in  aqueous  solution/' 

HYDRASTININE,  CHHnNO,  -f  H2O.  Crystals ;  melting-point, 
1 1 6°  to  117°.  Inactive  in  aqueous  solution.1 

CHELERYTHRINE  (Sanguinarine),  C17H15NO4.  Crystals; 
melting-point,  160°.  Inactive. 

Cinchona  Alkaloids  ' 

CUPREINE,  C19H22N2O2  +  2H2O.  Prisms  ;  melting-point, 
197°  to  198°.  The  following  determinations  on  the  alkaloid 
and  its  salts  were  made  by  Oudemans.15 

Absolute  alcohol.  ..  c ---  0.69,  1.24,  1.78° 

"     •••  O]£  -    -175-4,     -175-5,     -173-3° 
Alcohol  (97  p.  c.)..          c=  1.50,     [*]*  =    -175-3° 

Neutral  Hydrochloride,  C]C(H.,.;N2OrHCl -h  H2O.  Colorless 
needles. 

Water r  ^  0.567,  [«]^  -  157.1°;  alcohol,  [or]$  =    -184.7° 

"      c  =  0.871,         "    :  -154.8;  "    =      -182.0 

Absolute  alcohol  c       0.927,         "    =          169.7;  -199.8 

"     •  •  c       1.421,         ''  -167.3;  -196-7 

Acid     Hydrochloride,     CwHMN2Or2HCl.  Hard    crystals; 

-f  2H2O,  rhombic  crystals. 

Water,  c=    1.194  (hydrated),  [nr]}j-     —211.0°  ;  alkaloid,  [<*]^7  =  —283.8° 

"      c=    2.508            "                          —210.6;  —282.3 

"      c—   4.687            "                           -206.0;  —276.2 

"      c=   8.589           "                "  =    -200.4;           "  -268.6 

41      f-— 17.278           ''                "  =     -  191.1;           "  —256.2 
1  Freund,  Will  :  Ber.  d.  chem.  Ges.,  19,  2797. 

-  Eijkman  :  Rec.  trav.  chim.  Pays-Has,  5,  290. 

'  Freund  and  Rosenberg  :  Ber.  d.  cheni.  Ges.,  23,  404. 

*  Freund,  Will  :  Loc.  cit. 

Numerous  earlier  observations  on  the  rotation  of  the  alkaloids  were  made  by 
Bouchardat  :  Ann.  chim.  phys.,  [3],  9,  213:  Bouchardat  and  Boudet  :  J.  pharm.  Chim., 
[3],  23,  288  :  Buignet  :  Ibid.,  [3],  40,  268  ;  DeVrij  and  Alluard  :  Compt.  rend.,  59,  201. 
The  numerical  data  refer  to  Biot's  red  ray,  but  they  cannot  be  used,  as  the  nature  of 
the  solvent  and  the  concentration  are,  in  most  cases,  not  given 
'•  Rec.  trav.  chim.  Pays-Has.  8,  153. 


672  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Water,     ;     5.26  cc.  norm.  HC1    c  =--    2.088  (hydrated),  [a]^  =  —  210.8° 

alkaloid,  "  =  -282.6 

-f-  10.53  cc.  norm.  HC1  c  =  -  2.070  (hydrated),  "  = —  210.2 

alkaloid,  "  =  —  281.7 

-[-  22.73  cc.  norm.  HC1  c  —  21.987  (hydrated),  "  =  —205.5 

alkaloid,  "  =  —276.4 

-(- 52.63  cc.  norm.  HC1  c  -  2.085  (hydrated),  "  =  —199.5 

alkaloid,  "  =  —  267.8 

-f-  90.90  cc.  norm.  HC1  c  =-.  2.056  (hydrated),  "  =  —194.0 

alkaloid,  "  =    —260.9 

Neutral    Hydrobromide ,     C19H22N2O,.HBr  -f  H2O.       White 
needles. 

Water c  =  0.491,   [a]$  =    -  145.8°  ;  alkaloid,  [<*]$  =    -  192.7° 

"    =  —  191.1 

M    =-183-7 

"    =  —  181.1 


£  =I.I&>,  =  —  144.8 

Absol.  alcohol  c  —  1.434,        "   =      -  139.2 
c=  1.687,        "   =—  137.3 


Acid  Hydrobromide,  ClfHltNfO,.2HBr.     Crystals. 

Water £=1.564,   [a]g  =    -  189.0°  ;  alkaloid,  [or]^  =  -287.7° 

"     £  —  2.991,        "    -      -184.6;  —281.0 

"       C=  7.012,             "     =        -176.8;                   "                    *'      :  -268.6. 

Neutral  Hydroiodide,  C19H22N2OrHI.     Crystals. 

Water c  —  0.802,   [a]g  =    -126.3°;  alkaloid,  [or]^  ^  -178.4° 

Absol.   alcohol  c  =  0.982,        "  =  —  128.3;            "             "  -180.9 

Acid  Hydroiodide,  C19H22N2O2.2HI  (at  150°).   Yellow  crystals. 

Water £=1.504,  [a]g  =    -  151.2°  ;  alkaloid,  [a]^  ~  -283.2° 

"     £=1.491,        "    5      -147-6;  -276.4 

Neutral  Nitrate,  ClaH22N2O2.HNO3  +  2H2O.    White  needles. 

Water c—  1.129,  [al^  =        138.4°  ;  alkaloid,  [a]$  =  —  182.5° 

Add    Nitrate,    C19H22N2O2.2HNO3  +  HaO.       Light   yellow 
crystals. 

Water £=1.283,  Olg  =    -1794°;  alkaloid,  [a] ^  =  -289.1° 

"     £=2.347,        "    =      -193-4;  -283.2 

£-=3.815,        "    =     -188.9;  -276.7 

"     £       5-035,        "          -189.8;            "             "  -278.0 

"     £  =  6.551,        "   ..      -188.9;            "  -276.7 

Chlorate,  C19H22N2O2.HC1O3.     Fine  white  needles. 

Water c  -----  1.033,  [or]»j  =    -  144.9°  \  alkaloid,  [a]%  -  184.4° 


ALKALOIDS 


673 


Neutral  Sulphate,  C19HMN,OrHaSO4  +  2H2O.     Crystals. 
Water1 


=  0.905,     [<*]%    =      -  202.4°  ;  alkaloid,  [a]  g    =      -289.9° 
=  1.087,     l>]g=-  I97-I  "          IXlg    =-282.3 

[a]g-s=  -281.7 
[a]g  =  -282.8 
[a]£  =  —  286.6 
[a]  #  =  —  285.3 


<r  =1.110, 
f=  1.437, 
*•=  1.563, 
r=  1.605, 
£=2.130, 


=—  196.7 
-  -197-4 
=  —  200.1 
=—199-2 
=  —  197.0 


=r  —  282.2 
=-280.9 


"     .....  ^=2.766,     [a]  3    =--196.1  t 

Formate,  C19H22N2O2.CH2O2.     White  needles. 
Water,  £=  0.4804,     [o:]^  =  —  163.8°  ;  alkaloid,  [<*]$=  -  183.0°  (p.  167) 

Oudemans  has  also  carried  out  investigations  on  the  effect 
of  alkalies  (KOH,  NaOH,  L,iOH,  BaO.2H2,  NH3)  on  the 
specific  rotation  of  cupreine.2 

QUININE  (Methyl  ester  of  cupreine),  Q19H21N2O.OCH$ 
-f-  3H2O.  Crystals;  melting-point,  172.  8°.  3 

Ether  (d  —  0.7296)  .....  ^=1.5  to    6,     [a]«  =    -  158.7  +  1.911  c     1* 
Alcohol  (97  vol.  p.c.)..-  c  =  i       "  10,  —  145.2  +  0.657  c      I 

Chlorof.  -alcohol,  c  =  2,     [or]g  =    -  141.0  ;     c  =  5,     [or]jf  =  —  140.5 


Anhydride,  C20H24N.,O2.     Amorphous. 
Alcohol  (97  vol.  p.  c.)  £  =  i,  [0:]^=: —  170.5°  ;  c—  2, 
Chloroform c=2,       "    =  =  —  116.0°  ;  £=5, 


=  -  169.25' 
=  -  106.6 


The  following  observations,  a,  b,  and  r,  were  made  by 
Oudemans.6 

a.  Absolute  alcohol.  Determinations  for  different  concen- 
trations and  temperatures  : 


/. 

C  =   I. 

C  =  2. 

c  =  Z- 

c  =  4. 

£  =  5- 

c  =  6. 

0° 

-  I7I-4 

—  169.6 

~  167-9 

-I66.I 

—  164.2 

—  162.4 

5 

170.5 

168.7 

167.0 

165.2 

163.4 

161.6 

10 

169.6 

167.8 

I66.I 

164.4 

162.7 

160.9 

15 

168.9 

I67.I 

165.4 

163.7 

I62.I 

160.4 

20 

168.2 

166.6 

164.8    •;        163.2 

I6Z.6 

159-8 

1  Oudemans,  p.  166. 

-  Rec.  trav.  chim.  Pays-Bas,  9,    171. 

3  Grimaux  :  Compt.  rend.,  114,  672. 

4  Hesse  :  Ann.  Chem.  (Liebig).  176,  206. 
•-  Hesse:  Ibid.,  176,  208. 

«  Ibid.,  182,  44- 
43 


674  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

b.  Aqueous  alcohol,  c  =  1.62,  /  —  17°  : 

Strength  of  alcohol  in  p.  c..       100.0      94.9    93.5     90.5    83.3     73.9    65.1 
[a]z>  ....................  -167.5°  169.7  170.4  171.9  174.3  176.1   176.5° 

f  Benzene.  Toluene.  Chloroform. 

*r  =  o.6i  0.39  0.775  1.465 

[a]£  =    -136  -127  -126  -117° 

Chloroform-alcohol  mixture-  .  .  •  p  =  0.7  to  2.3,     [a]^8-1^  =    -  164.4°  ' 

Hydrochloride,     C20H.,4N2O,-HC1  -f-  2H,Q-       Long    asbestos- 
like  prisms. 

a.  Water  .........     c  =  1.54  to  1.62  (calc.  as  alkaloid), 

[cr]^  =    -  133.7°  (anhydrous)  ;  alkaloid,  [a]1^  =    -  163.6°. 
Absolute  alcohol     c  =  1.54  to  1.62  (as  alkaloid), 

[or]  15  =    -  138.0°  (anhydrous)  ;  alkaloid,  [or])?  =    -  169.0°. 

The  following  data,  b  to  e,  are  by  Hesse.3 

b.  Water  ..............  c  =  i  to    3,  [a]'j  =    -  144.98  -f  3.15  r, 

alkaloid,       "   =     -  167.41  -f-  4.71  c, 

2mol.  HC1  +  water,  c  =  i  to    7,        "a     -  229.46  -f  2.21  r, 
alkaloid,       '*   =     -  280.78  +  3.31  r, 
Alcohol  (97  vol.  p.c.)  c  =  i  to  10, 

[a]/>  =    -  147.30  +  1.958  c  —  0.1039^'  -f  0.0021  1  c\ 

c.  When  aqueous  alcohol  was  used,    the   specific   rotation 
showed  a  maximum  with  60  volume  per  cent,  of  alcohol.     For 
c  =  2  and  t  =  15°,  the  following  figures  were  obtained. 

Alcoholic  strength: 

Vol.  p.  c.      97                90                 85  80  70 

O]z?  -    -143.86  -160.75  -168.25  -174.75      -182.27 

Alcoholic  strength  : 

Vol.  p.c.      60                50                  40  20  o(  water) 

[>]/>:=    -187.75  -187.50      -182.82  -166.59     -I38.750 

Chloroform-alcohol  mixture,  c  —  2,     [«]J|  =    -  126.25° 

d.  Chloroform.     Anhydrous  salt,  c  =  0.9  to  9  : 
[«]£  =  -  81.81  +  23.756  c  -  3.9556  c1  +  0.2198  r\ 

e.  Dilute  hydrochloric  acid.     To  i  mol.  of  salt,  n  mol.  HC1, 

C  =  2. 

n  o  i  2  4  jo  16 

=    -138.75       -223.2        -225.7       -223.6       -213.9       -209.5° 


Ztschr.  anal.  Chem.,  27,  549. 
a  Oudeinans  :  Ann.  Chem.  (Uebig),  i8a,  46. 
1  Ibid.,  176,  210. 


ALKALOIDS  675 

Fuming  hydrochloric  acid,  c  —  2,  [>]'j  =     -  158.8°. 

LHquinine  Sulphate,  (C20H.,4N2O2)2H2SO4  +  8H2O.    Crystals. 
Alcohol  (80  vol.  p.  c. ) r  ==  2,  M/5  =  —  162.95° 

"         (60  "  ) C=2,  "      =—166.36 

Water  +  4  mol.  HC1 r  =  2,  "    =  —  239.2 

Chloroform-alcohol  mixture. . .  r  =  i  to  5,          "    =  —  157.5  -f-  0.27  c 
40  cc.  normal  HC1  -j-  water c  =  8  (anhydrous),  [nr]^  =    —  229.03°  * 

(C20H24N2Oa)2H2S04  +  7V2  H20. 

Absol.  alcohol,  c  =  1.54  to  1.62  (calculated  as  alkaloid)  ;  salt  anhydrous, 

f  a]  17  =  —  157.4°  ;  alkaloid  [<*]^  =  —  214.9°  3 

Absol.  alcohol,  c  =  1.3,     [a]1/,  =    -  155.2°  ;  c  —  2.0,   [ar]^  =    -  158.4°  * 

Quinine  Sulphate,  C20H24N2O2.H,SO4  -f  7H8O.   Rhombic  crys- 
tals. 

Water c  —  i  to  6,  salt,  [a]^  =  --  164.85  -f  0.31  c ; 

alkaloid,  [<*]^  =   —  278.71  +  0.89  c, 

Alcohol  (97   vol.  p.  c.) c  =  2,     [a]g  =  — 134.75°    5 

(80  ) c=z,          "   =  —  142.75 

(60          "        ) f=a,          "   =  -  I55-91 

Chloroform-alcohol  mixture-  c  =  2,          "   = — 138.75 

Water c  —  1.54  to  1.62  (calc.  as  alkaloid),  1s 

[a]g  —   —  213.7°  (anhydrous)  ;  alkaloid,  [tr]1^  =  —  278.1° 
Absol.  alcohol  c  =  1.54  to  1.62  (calc.  as  alkaloid), 

[a]^7  =  —  134.5°  (anhydrous)  ;  alkaloid,  [cr]^  =  —  227.6° 

The  specific  rotation  of  alcoholic  solutions,  with  c  =  2,  de- 
creases, with  elevation  of  temperature,  0.65  for  i°C.6 

Quinine   Disulphate,    C20H24N2O,.2H2SO4  -f  7H2O.     Prisms. 

Water c  =  2  to  10,     [a]TJ  =    -  170.3  -f  0.94  c\  7 

Alcohol  (80  vol.  p.  c. ) f=i,  "  =  —  154.5 


(80 


j 


C^H^NA^H.SO,  +  4H20. 

Water  ............   c  =  2  to  10,     [a]  js  =  _  155.69  +  1.14  c 

Alkaloid         "  =     -  284.48  -f  3.79  c 

1  Hesse  :  Ann.  Chem.  (Liebig),  176,  213. 

2  Hesse:  Ibid.,  205,  219. 

:!  Oudemans  :  Ibid.,  i8a,  46. 

«  Oudemans:  Rec.  trav.  chim.  Pays-Has,  i,  27. 

5  Hesse  :  Ann.  Chem.  (I,iebig),  176,  215. 

e  Draper:  Am.  J.  Sci..  [3],  n,  42- 

J   Hesse:  Ann.  Chem.  (Liebig),  176,  217. 


676  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

i  mol.  quinine  hydrate  -j-  3  mol.  H.,SO4  -f  water  to  100  cc., 
c  =  i  to  5. 

[o-pj  (calc.  as  hydrate)  =  -  246.63°  -f-  3.08  c 

[a]g  (alkaloid)  -  287.72°  +  4.19* 

i  mol.  sulphate  -f  2  mol.  H2SO4  -f-  water  to  100  cc.     c  =  i 
to  10. 
Salt     [a]»s  =     -  171.68  -f  0.78^;    alkaloid,   [a]Jj  =    -  290.36°  +  2.23  c 

i  mol.  disulphate  +  i   mol.  H2SO4  +  water  to  100  cc.    c  = 
2  to  6. 
Disulphate  [a]g=  -  153.87  -f  0.92  r;  alkaloid,  [a]  ^  =  —281.  15°  +  3.1  \c  * 

Oxalate,  (CMHJ4N2O2)2C2H2O4  -f  6H2O.     Long  prisms. 
Chloroform-alcohol  mixture  .....  c  =  i  to  3,  [orj^s  =    -  141.58  -j-  0.58  c  2 

.Sa/l  w/M  j  J/<?/.   Water  of  Crystallization. 
Absolute  alcohol  ..........   c  —  1.54  to  1.62  (calc.  as  alkaloid), 

[a]£  =    -  131.4°  (anhydrous)  ;  alkaloid,  [a]^  =    -  160.5°  3 

Quinine  Sulphonic  Acid,  C20H23N2O,.HSO.{  -f  H2O.    Prisms  ; 
melting-point,  209°. 

3  mol.  HC1  -f  water.  .....   c  =  2  (anhydrous)  [«]$  =    -  182.2°  * 

Cupreine  Ethyl  Ester,  C19H21N2O.OC2H5.     White  amorphous 
mass  ;  melting-point,  160°. 

Absolute  alcohol  ...........    [or]/)  =    -  169.4°  5 

Cupreine    Propylester   Sulphate,    (C19H21N2O.OC3H7)2.H2SO4 
-f-  iV,H2O.     Crystals  ;  melting-point,  223°  to  224°. 

Concentrated  aqueous  solution  of  the  salt  dried  at  100°  : 
[«]S=  -  229.5°  « 

Cupreine  Isopropylester  Sulphate,  (C19H21N2O.OC3H7)2.H2SO4 
-f  H2O.     Crystals  ;  melting-point,  154°. 

Concentrated  aqueous  solution  of  the  salt  dried  at  125°  : 


Hesse  :  Ann.  Chem.  (I^iebig),  176,  182. 

Hesse:  Ibid.,  176,  218. 

Oudemans  :  Ibid.,  i8a,  46. 

Hesse:  /bid.,  267,  141. 

Grimauz,  Arnaud  :  CompJ.  rend.,  na,  1364. 

Grimauz  and  Arnaud  :  /bid.,  114,  672. 

Grimauz  and  Arnaud  :  I^oc.  cil. 


ALKALOIDS  677 

Cupreine- Quinine      (Homoquinine) ,     Ci9H2.jN,O.j.C.,0H24NJO, 
-f  4H2O.     Triclinic  crystals  ;  melting-point,  177°. 
Alcohol c  =  5,    !>]/>=   -  158°  * 

Sulphate,   (C19H22N202.C20H24N20.2)2-H2S04  +  6H,O.     Color- 
less prisms. 

40  cc.  norm.  HC1  -j-  60  cc.  water,  c  =  5  (anhydrous),   [a~\is  =    —  235.6° * 
Water  with  0.5  p.  c.  H2SO4,  c  =  5,     [a]D  =    -  209°  )3 

"  "       I.O       "  "          f=5,  "    =       —220     j 

Nitrocamphor  Quinine,  CWH24N2O2  -f-  2C10HU(NO2)O  +  HaO. 
Needles;  melting-point,  about  131  (decomposes). 

Alcohol p  =  2.72,     [or]y  =  +  45-9°  * 

Acetyl    Quinine,     C20H23(C2H3O)N2O2.       Prisms;    melting- 
point,  108°. 

Alcohol  (97  vol.  p.  c.) c  =  2,     [a]'J  =     -    54-3°  j5 

3  mol.  HC1  +  water c  =  2,  -  114.8   j 

Propionyl  Quinine,    C,0H23(C3H5O)N,O2.     Rhombic  prisms; 
melting-point,  129°. 

3  mol.   HC1  +  water c  =  2,     [a]'J  =    -  108.8°  6 

APOQUININE,    C19H82N2O2  -f  2H2O.      Amorphous ;   melting- 
point,  1 60°  (turns  brown). 

Alcohol  (97  vol.  p.  c.) c  =  2  (anhydrous),  [a]g  =    -  178.1°)  7 

3  mol.  HC1  +  water c  =  2  -  246.6  j 

Alcohol  (97  p.  c.) c  =  0.7877,  Mg=    -  217-1°  } 

Diacetylapoquinine,  C19H20(C2H3O)2N2O2.     Amorphous. 

Alcohol  (97  vol.  p.  c.) f=2,     \a\^=     -    6i.8°|9 

3  mol.   HC1  -f  water c  =  2,  -107.5  j 

Hydrochlorapoquinine, ,  C19H23C1N2O2  -f  2H2O.    Flakes  ;  melt- 
ing-point, 1 60°. 

Alcohol  (97  vol.  p.  c. ) c  =  2  (anhydrous),     [or]g  =  -  149- J°  }  w 

3  mol.  HC1  +  water c=2  -  245-7 

1  Howard,  Hodgkin  :  J.  Chem.  Soc.,  41,  66  :  Ber.  d.  chem.  Ges.,  15,  Ref.  379. 

2  Hesse  :  Ann.  Chem.  (I^iebig),  325,  104. 

3  Howard,  Hodgkin  :  J.  Chem.  Soc.,  41,  66;  Ber.  d.  chem.  Ges.,  15,  Ref.  734. 
Cazeneuve  :  Bull.  soc.  chim.,  49,  97. 

Hesse  r  Ann.  Chem.  (I,iebig),  205,  3'7- 

Hesse  :  Loc.  cit.,  p.  358. 

Hesse  :  I^oc.  cit.,  p.  323. 

I^ippmann  :  Ber.  d.  chem.  Ges.,  28,  1972. 

Hesse,  p.  337. 

Hesse,  p.  341. 


678  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

CHITENINE,  CWH«N2O4  +  4H2O.     Crystals. 
Alcohol    (d  —  0.958) p  =  0.1093,     d  =  0.9595,     [«]/>  =    —  142.7°  * 

QUINICINE,   C20H24N2O2.     Amorphous;   melting-point,   60°. 
Chloroform    c=2,     [a]%  =  +  44.1°  2 

Oxalate,  (C20Ha4N2O2)2C2H2O4  +  9H2O.     Crystals. 

Chlorofonn-alcohol  mixture c  —  I  to  3,     [<*]$  =  -f  20.68—  1.14^-1  s 

Water c  =  2,  =  -f    9.54 

Water  -f  2  mol.  H2SO4 c  =  2,  =  +  15.54 

QUINIDINE  (Conquinine),  C20H24N2O2.  Crystals  (from  ben- 
zene) ;  melting-point,  171.5°  (corr.). 

i  vol.  alcohol  (97  vol.  p.  c. )   (/>  =  2.1,       [<*]^'9  =  +  269.7°  )* 
4-  2  vol.  chloroform         (p  =  1.06,     [<*]$    -  -  -j-  274.7 

Benzene r— 1.62,  =+195.2 

Toluene ^7=1.62,          "      =+206.6 

Chloroform ^=1.62,          "        =  +  228.8 

Alcohol  ( wt.  p.  c. ;  loo. o        95.3        90.5        85.0        80.0        75.0 \* 

W%=          +255.4°     257.6       259.0       259.4      259.3       259.4} 

Alcohol  (97  vol.  p.  c.) c  =  i  to  3,     [tf]^f  =  +  269.57  —  3.60^!  T 

Chloroform c=  1.756,  "    ==  +  230.35°  J 

Alcohol,  \a]j  =  268.6°  ;  methyl  alcohol,  [«]7  =257.5°. 
Wyrouboff  explains  this  difference  by  formation  of  alco- 
holates  :  (CWH24N2O2)CH4O,  [«]y  =  +  236.1°  and  (C20H24N2O2) 
C2H60,  [XL  =  +  235.3°. 

CwHj.NA  +  2!/2H2O  (from  water)  : 

Alcohol  (97  vol.  p.  c.) <r=ito3,     [«])S  =  -f  236.77  —  3. QIC}  9 

(80        "  f=2,  =4-  232.7° 

Chloroform-alcohol  mixture  . .  c  =  i,  =  +  244.5 

"         C=2t  "  =  +  241.75 

Neutral  Hydrochloride,  C20H24N2O2-HC1  +  H.2O.  Asbestos- 
like  prisms. 

Skraup:  Ann.  Chem.  (Uebig),  199,352. 

Hesse:  Ibid..  178,260. 

Hesse,  p.  261. 

l,enz  :  Ztschr.  anal.  Chem..  37,  571. 

Oudemans  :  Ann.  Chem.  (I^iebig),  i8a,  44. 

Oudemans:  Ibid.,  182,  48. 

Hesse :  Ibid.,  176,  203;  i8a,  128. 

Compt.  rend.,  115,  832. 

Hesse  :  Loc.  cit. 


ALKALOIDS 

Water c    ^  i  to  2,  [a]$  ==  +  205.83  —  4.93  c\ } 

Calculated  for  alkaloid,  =  +  240.45  —  6.60  c 

Water  +  *  "jol    HC1 j =  ,  t  ..  _  f 

for  i  mol.  alkaloid    j 

Calculated  for  alkaloid.          "    =  -+-  338.37  —  4.52  c 

Alcohol  (97  vol.  p.  c.) c  —  2  to  5,  =  +  212.0    —  2.56  <: 

(80  "  ) C=1  •"      n_     -~    230.25 

C20H24N2O2.HC1  +  2H2O.     c  ==  2.0  (anhydrous)  : 

Alcohol 

Water.     Abs.  alcohol.  (90.5 wt.  p.  c.). 

Salt  (c  =  1.58  alkaloid),     [«])]  =  +  190.8°         199.4°  213.0° 

Alkaloid  (calc.) =+233.6          244.1  260.7 

Acid  Hydrochloride,  C,0H.,4N2O2.2HC1  +  H2O.     Prisms. 
Water c  ---  2,     [or]  jj  =  +  250.3°  3 

Neutral  Sulphate,  (C20H24N2O2;2.H2SO4  +  2H2O.     Prisms. 

Water c—i  [>]£  =  +  i?9-54°  1 ' 

alkaloid,        "    ==  +  215.55    I 

4  mol.  HC1  +  water,  c  =  2  (anhydrous),  =  +  286.4 

alkaloid,       "    =  +  329.8 

5  mol.  H.,SOt  +  water,  r=  2  (anhydrous),      "    ==  +  281 

alkaloid,       "    ==  +  323 

Absolute  alcohol c  =  2.8  (anhydrous),  [a]$  =  +  211.5 

alkaloid,        "  —  +  255.2 

Alcohol  (80  vol.  p.c.)  c=2,  [or]^s  =  +  218.2° 

(60       "        )  c=  2,  "   =  +  227.0 

Chlorof. -alcohol  mix.  c  —  2,  =  +  209.25 

Chloroform c  =  3  (anhydrous),  =  +  184.2 

f  =5.  r  +  l8°-1 

Acid  Sulphate,    C20H24N2O2.H2SO4  +  4H2O.      Asbestos-like 
needles. 

Water c  =  2  to  8,  [a]g  =  +  212.0    —0.8    c    3 

alkaloid,  =  +  323-23  —  1.86  c 

2  mol.  H2SO4  —  water c  =  i  to  10,        "    =  =  +  215.49  —  1.41  c 

alkaloid,          "    -  =  +  328.55  —  3.27  c 

Alcohol  (97  vol.  p.  c.) c  =  2,  =  +  183° 

Nitrate,  C20H24N2O2.HNO3.     Short  thick  prisms. 
Absol.  alcohol,  c  =  2.17,     [a]1^  =  —  199.3  ;  alkaloid,  [a]g  =  +  232.6° 

1  Hesse:  Ann.  Chem.  (I^iebig),  176,  225. 

'-'  Oudemans  :    Ibid.,  182,  49. 

3  Hesse  :  Loc.  cit. 

*  Hesse. 

5  Oudemans. 

*>  Oudemans  :  Loc.  cit. 


680  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Oxalate,  (C20H24N2O2)2C2H2O4  -f  H,O.     Very  small  crystals. 
Chloroform-alcohol  mixture c  —  i  to  3,     [<*]$  =  +  189.0  —  2.18  c1 

Acetyl  Quinidine,  C,0H23(C2H,O)N2O,.     Amorphous. 

Alcohol  (97  vol.  p.  c.) c  =  2,     [a]js  =  +  127.6°  |2 

3  mol.  HC1  +  water c  —  2,  =  +  158.6    J 

APOQUINIDINE,    C19H2aNaO2  +  2H2O.     Amorphous ;    melt- 
ing-point, 137°. 

Alcohol  (97  vol.  p.  c.) c  —  2  (anhydrous),   [a]«  ==  +  155.3°  1 3 

3  mol.    HC1  +  water c  =  2  "  =  +  216.5    J 

Diacetylapoquinidine ,  C19H20(C2H3O),N2O2.     Resin  ;  melting- 
point,  60°. 

Alcohol  (97  vol.  p.  c. ) c  =  2,     [or] }$  =  +  40.4°  ! 4 

3  mol.  HC1  +  water r  =  2,          "    ==  +  78.4    j 

Hydrochlorapoquinidine,     C19H23C1N2O2  -f  2H2O.     Crystals ; 
melting-point,  164°. 

Alcohol  (97  vol.  p.  c.) c  =  2  (anhydrous),  [tf]$  —  +  203.7°  i5 

3  mol.  HC1  +  water c=2  "  =  +  258.4    j 

Diacetylhydrochlo rapoquin idine,  C19H21(C2H3O)2C1N2O,. 
Rhombic  leaves  (from  ether)  ;  melting-point,  168°. 

3  mol.  HC1  +  water c  —  2,     [or] jf  =  +  94.6°  6 

CINCHONINE,   C19H2aN2O.     Crystals;  melting-point,   255.4° 
(corr.).7 

Alcohol  (97  vol.  p.  c.) r  =  o.5,     [a] y>  =  +  226.26°  -j  8 

t=I,  "   =  +  225.96  j- 

Chloroform-alcohol  mixture c=  i  to  5,     "    ==  +  238.8  -  i.46rJ 

Absolute  alcohol c  =  0.5  to  0.75,     [or]  %  —  +  223.3°  1  9 

Chloroform £  =  0.455,  =  +  214.8 

£  =  0.535,  "    -=  +  212.3 

^=0.560,  =  +  209.6    J 

Chlorof. -alcohol  mixture  p  =  i  .061,  rfj»-8  =  1.2508,   [or] Jf-8  =  +  239.40°  •»  10 
^=2.123,  fllj°-a  =1.2497,   [«]^-2  =  + 234.55    i 

Absolute  alcohol £  —  0.4715,     [«]],  =  +  222.92°  u 

Hesse. 

Hesse  :  Ann.  Chem.  (Liebig),  305,  318. 

Hesse  :  Ibid.,  p.  326. 

Hesse  :  Ibid.,  p.  327. 

Hesse  :  Ibid.,  p.  343. 

Hesse  •  Ibid.,  p.  352. 

I,enz  :  Ztschr.  anal.  Chem.,  37,  572. 

Hesse  :  Ann.  Chem.  (lyiebig),  176,  228. 

Oudemans :  Ibid..,  182,44. 

10  lyenz  :  Loc .  nt. 

11  I'um  :  Wien.  Monatsh.  Chem.,  13,  683. 


ALKALOIDS  68l 

From  benzoyl  cinchonine. 

Absolute  alcohol c  =  0.75,     [«]^7  — -f-  233.1°  l 

Neutral  Hydrochloride,  C19H2,N,O.HC1 -f  2H,O.  Rhombic 
crystals. 

Water c  =  0.5  to  3,     [a]^  =  +  165.50  —  2.425  c^  * 

alkaloid,  =  -j-  204.46  —  3.7      c 

2  mol.  HCI  +  water c  =  I  to  7,  =  +  214.0    —  1.72    c 

alkaloid,          "  =  +  264.37  —  2.625  c 
Alcohol  (97  vol.  p.  c.)  c  —  i  to  10,  [tfpj  =  179.81  —6.314*:  +  0.8406 £ 

—  0.0371^  | 
(80         "      )  c=  2,  "    ==  +  188.9° 

(60  "         )    C=2,  ""=?  +   195-5° 

Chlorof. -alcohol  mixt.  c=  2,  -  +  152.0  j 

Add  Hydrochloride,  C19H22N2O.2HC1.     Prisms. 

Water t  =  3,     [or]£  =  -f  206.1°  :i 

Neutral  Sulphate,  (C19H2.,N2O)2.H.,SO4  +  2H2O.  Monoclinic 
crystals. 

Water c  =  i  to  2,     [ar]*s  =  -f  170.3    —  0.855  c  -»  * 

alkaloid,  "    =  -j-  206.79  ~~  I-26    <" 

21 2  mol.    H2SO4  -j-  water c  =  0.5  to  6,      "    ==  +  219.10 — 1.85    c 

alkaloid,  =  +  266.07  —  2.69    c  ^ 

Alcohol   (97  vol.  p.  c.) r  =  3  to  10,       "   ==+  193.29  —  0.374  r 

(80          "         ) C=2,  "    =  +  202.95 

"  (60  "  ) <~  =  2,  =  +  204.14 

Chloroform-alcohol  mixture-  c  =  2,  =  +  185.25 

According  to  Wyrouboif,5  the  sulphate  and  selenate  of  cin- 
chonine ([<*]y  ==  234°)  take  up  one  molecule  of  crystallization 
alcohol  from  alcoholic  solution. 

(C19H29N20)2H2S04  +  C2H60,    [or],  -    +  185°  ; 

(C19H22N20)2H2Se04-|-  C2H6O,        ;   =  +  182.5°. 

Oxalate,  (C19H22N2O)2C2H2O4  +  2H2O-     Prisms. 
Chloroform-alcohol  mixture c  =  i  to  3,     [«r]^  =  165.46  —  0.763  r 6 

Wyrouboff7  gives,  also,  the  constants  of  rotation  of  cincho- 

1  I^eger:  Compt.  rend.,  117,  no. 

-  Hesse  :  Ann.  Chem.  (I^iebig),  176,  230. 

3  Hesse  :  Ibid.,  376,  91. 

4  Hesse  :  Ibid.,  176,  231. 
•"'  Compt.  rend.,  115,  832. 

c  Hesse:  Ann.  Chem.  (Liebig),  176,  232. 
~  Ann.  chim.  phys.,  [7],  i,  5. 


682  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

nine  salts  which  have  separated  from  different  solutions  com- 
bined in  crystalline  form  with  part  of  the  solvent. 

Diisobutylcinchoninehydrobromide,  C19H22N2O.C4H,,Br-f  H..O. 
Melting-point,  176°. 

Water p  =  i,     [a]}?  =  -f-  125°  ' 

Acetylcinchonine ,  C19H21(C2H3O)N2O.     Amorphous. 

Alcohol  (97  vol.  p.  c.) c  —  2,     [«r]^f  =  +  114.1°  >2 

3010!.    HC1  +  water c  =  2,          "      ^+139.5    J 

Hydrochlorcinchoninedihydrochloride,  C19H2SC1N2O  .  2HC1. 
Monoclinic  crystals. 

Water c  =  3,        [or]g  = -f  185.9°  j3 

i  mol.  HC1  -r  water r  =  2.4  =  -f  187       i 

/?-CINCHONINE.  C19H22N2O.  Probably  identical  with  one  of 
the  bases  made  by  Jungfleisch  and  Leger  (see  below ) .  Crystals  ; 
melting-point,  250°  to  252°. 

Absolute  alcohol c  =  0.4715,     [#]/>  =  -f  195.77°  4 

tf-CiNCHONiNE,    C19H22N2O.     Prisms;   melting-point,    150°. 

Alcohol  (97  p.  c. ) c  =  i,     [or] $  =  +  125.2°  •» 5 

2  mol.   HC1  -f  water...  f=i,  =+176.9 

4     "         "-f       '*    ...  c=it          "    =  -f  178.2 


a-IsociNCHONiNE  (Cinchoniline) ,  C19H22N2O.  Anhydrous 
monoclinic  crystals  ;  melting-point,  126°;"  125°  to  i27°;7  130.4° 
(corr.).1 

Absolute  alcohol c  =  3,        [a]^  =  -f-  5 1 .6°  !( 

Alcohol  (97  p.  c) c=i,  =  -f  53.22  ) 10 

f  =  0.5,    Mg  =  +  50.3  i 

According  to  Hesse,  this  last  value  is  wrong,  because,  as  he 
finds,  the  rotation  increases  with  increasing  dilution. 

2  mol.  HC1  +  water c=it     [a]g  =  + 59.15 

4     "       "      +      "     c—it  =  +  63.10 

Vial  :  J.  pharm.  Chim.,  [5],  30,  52. 

Hesse  :  Ann.  Chem.  (lyiebig),  205,  321. 

Hesse.  Ibid.,  376,  no. 

Pum  :  Wien.  Monatsh.  Chem.,  13,  683. 

Jungfleisch,  Leger :  Compt.  rend.,  118,  31. 

Hesse  :  Ann.  Chem.  (Uebig),  376,  93. 

Comstock,  Konigs  :  Ber.  d.  chem.  Ges.,  30,  2521. 

Jungfleisch,  Llger  :  Compt.  rend.,  106,  658. 

Hesse. 

Jungfleisch,  I^eger. 


ALKALOIDS  683 

Hydrochloride,  C19H2,N,O.HC1  +  2  or  3H2O.  Prisms  ;  melt- 
ing-point, 226°. 

In  pure  aqueous  solution,  the  salt  with  2  molecules  of  water, 
for  c  =  2.5,  and  the  salt  with  3  molecules,  for  c  =  4,  do  not 
rotate  the  plane  of  polarized  light. 

Salt  with  2  mol.  H,O. 
3  mol.  HC1  +  water,  c=4,     [a]g  =  +  40.6°  ;  alkaloid,  [a]$  =  -f  50.6°  ! 

Salt  with  3  mol.  H2O. 

Water r=i,  [<*]£=+    5-o° 

2  mol.    HC1  -f  water  c  =  i,  =  +  59-3 

4     "          "   +      "       <r=r,  =  +  63.1 

From  this  difference  in  optical  behavior,  Hesse  concludes 
that  o'-isocinchonine  is  different  from  cinchoniline. 

Chlor-ct-isocinchonine,  C19H23C1N.,O.  Anhydrous  colorless 
prisms  ;  melting-point,  172°. 

Absolute  alcohol c  =  1.868,     [a] Jf  ==  +  67.6°  s 

/?-IsociNCHONiNE  (Cinchonigine) ,  C19H22N2O.  Prisms; 
melting-point,  125°. 

Absolute  alcohol c=l,     [or]g  =   —  53.12°)* 

"      f=3,          "   =-55-io  j 

Colorless  prisms  ;  melting-point,  128°  (corr.). 

Alcohol  (97  p.  c.) f'=J,        [a]g  =   -6o.i°>|5 

^7  =  0.5,     [ajg  =  — 61.16  I 

2  mol.    HC1 -f  water c=i,  —40 

4     "         "     -r      "     c=i,  -38.21  -1 

Hydrochloride,  C19H,2N2O.HC1  -f  H2O.  Prisms;  melting- 
point,  201°. 

Water c=I,     [a]^  =     -    68.10°  -j  6 

44     f  =  2  -    71. < 

2  mol.  HC1  -f  water. . .  c  =  2 
2  "  "-r  "  —  ^=5 
5  •«  «  -f  »  ...  c=2 
Chloroform c  =  2 

Hesse. 

Jungfleisch,  L,£ger. 

Hesse  :  Ann.  Chem.  (Liebig),  276,  97. 

Hesse  :  Ibid.,  a6o,  215 

Jungfleisch,  I,6ger  :  Compt.  rend.,  106,  358. 

Hesse  :  Ann.  Chem.  (Uebig),  a6o,  216. 


684  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

As  distinguished  from  all  other  di-acid  cinchona  alkaloids, 
the  rotating  power  of  this  alkaloid  increases  with  the  concen- 
tration, but  decreases  with  increase  of  acid. 

C19H22N2O.HC1  +.2H2O.  Colorless,  prismatic  needles; 
melting-point,  213°  (corr.). 

Water c  =  i,     [a] 55  =   -65.41°' 

CINCHONIDINE,  C19H22N2O.     Needles. 

Alcohol  (97  p.  c. ) c—  0.75,     [a]-D  =  +  195.0°  2 

Alcohol £1=0.75,     [a]^  =  +  201.4°  -\  3 

2  HC1  +  water p  =  i,  =+228.9     I 

2HC1+      "      p  •=  1.5  "==  +  225.13! 

4HC1+      "      p=it  =+  226.3    J 

APOCINCHONINE,  C19H22N2O.     Prisms  ;  melting-point,  209°  ;4 

228°.5 

Alcohol  (97  p.  c.) r=i,          [a]$  =  +  160.0°  ^  6 

2  mol.  HC1  +  water-   •«  r  —  2,  "    =-(-212.5 

3  "        "    +      "     ....   c=  2,  "   ==  -f  212.3 
Chloroform  mixture....   c  =  3,  =+  197.5    1 
Absolute  alcohol c  =  1.56,     [or]£  —  +  159.7    8 

Hydrochloride,  C19H22N2O.HC1  +  2H8O.     Needles. 

Water c  —  0.006,     [or]g  =  +  139.0°  ;  alkaloid,  [a]1/;    =  -f-  171.9° 

c  =  o.oio,  =  +  138.5  ;  =+171.3 

f  =  0.015,  =  +  138.5;  =+171.3 

Hydrobromide,  C19H22N2O.HBr  +  H2O.     Needles. 
Water c  =  0.0076,   [a]£  =  +  126.2°  ;  alkaloid,  [a]g  =i  +  168.7° 

Hydroiodide,  C19H22N2O.HI  +  H2O.     Needles. 

Water c  —  0.006,     [a]g  =  +  117.2°  ;  alkaloid,  [a]1^  =  +  175.5° 

Sulphate,  (C19H22N2O)2.H2SO4  +  3H2O.     Needles. 
Water c  —  0.0048,   [or]^  =  +  130.0°  ;  alkaloid,  [a]'J  =  +  164.0° 

Chlorate,  C19H22N2O.HC1O3.     Needles. 
Water £==  0.0069,   [a]^  =  +  129.0°  ;  alkaloid,  [or]jf  =  +  166.2° 

Junjffleisch,  L6ger  :  Compt.  rend.,  106,  358. 

Jungfleisch,  I^eger  :  Ibid.,  105,  1257  ;  Bull.  soc.  chim.,  49,  747. 

JungfleiMh,  Mger:  Compt.  rend.,  118,  536. 

Hesse  :  Ann.  Chem.  (I^iebig),  205,  330. 

Hesse:  /hid.,  276,  115. 

Hesse  :  /hid.,  205. 

Hesse  :  /Wrf.,  276. 

iiians  :  Rec.  trav.  chim.  Pays- Has,  i,  175. 


ALKALOIDS  685 

Perchlorate,  C19H,,N2O.HC1O,  +  H,O.     Needles. 
Water £  =  0.0052,  [<*]£=  +  124.9°  \  alkaloid,  O]£  =  -|-  I75-301 

Oudemans1  studied,  further,  the  effect  of  acids  (HC1,  HBr, 
HN03,  HC103,  HC104,  CH.A,  C2H4O,,  H2SO4,  C2H2O4,  H3PO4, 
C6H8O.)  on  the  rotation  of  apocinchonine. 

Acetylapocinchonine,  C19H21(C2H3O)N2O.     Crystals. 

Alcohol  (97  vol.  p. c.) c  =  i,     M'J  =  +  71.4°  •>  - 

3  mol.  HC1  -f-  water **  =  2,  =  +  97.9    j 

Chlorapotinchonine ,   C19H,3C1N.,O.     Needles  ;  melting-point, 

i97°. 

Alcohol  (97  vol.  p.  c.)   ...  r  =  o.5,  M^  =  +  205.4 

3  mol.  HC1  —  water c  =  2,  =  +  208.0 

Alcohol  (97  vol.  p.  c.) c  —  0.4745,     [«]^  =  +  2i 

....     C  =  0.2655,       [«]XJ  =  +  2I 

Neutral  Hydrochloride,  C19H,3C1N2O.HC1  -f  H2O.  Needles. 
Water c  =  0.0045,  [«]^  =  +  l65-9°  ;  alkaloid,  [cr]^  =  -f  193.2° 

Add  Hydrochloride,  C19H23C1N20. 2HC1.     Prisms. 
Water ^  =  0.0197,  [or]1^  =+  185.0°  ;  alkaloid,  [a]£  =  +  226° 

Sulphate,  (C19H23C1N20),H2S04  +  3H2O.     Needles. 
Water c=  0.005,     C^Pj  =  +  156.6°  ;  alkaloid,  [a]^  =  -f  192.5° 

Nitrate,  C19H2SC1N2O.HNO3.     Needles. 
Water c=  0.005,     |>]£  =  +  173.5°  ;  alkaloid,  [a]^  =  +  194.8° 

Chlorate,  C19H33C1N2O.HC1O3.     Crystals. 
Water c  =  0.005,     [or]£  =  +  155.3°  ;  alkaloid,  [or]£  =  -f  I94-904 

On  the  effect  of  acids  (HC1,  HBr,  HNO3,  HC1O3,  HC1O4, 
CH202,  C2H402,  H2S04,  C2H204,  H3PO4,  C6H8O7)  on  the  specific 
rotation  of  chlorapocinchonine,  see  paper  of  Oudemans.4 

AcetylChlorapocinchonine,  C19H22(C2HSO)C1N2O.  Amorphous 
varnish. 

Alcohol  (97  vol.  p.  c.) c  —  2,     [a]g  =  +  108.0° 

3  mol.    HC1  -f-  water c  =  2,  =   f  118.8 

Oudemans :  Loc.  cit. 

Hesse  :  Ann.  Chem.  (Liebig),  305,  338. 

Hesse  :  Ibid.,  p.  349. 

Oudemans:  Rec.  trav.  chim.  Pays-Bas,  i,  182. 

Hesse  :  Ann.  Chem.  (Liebig),  205,  354. 


686  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

DIAPOCINCHONINE,  CMH44N4O2.     Amorphous. 

Alcohol  (97  vol.  p.  c.  )  .  .  .  .   c  =  2,     [«]  g  =  +  20.0°  •>  ' 
3mol.    HC1  +  water  .....  c  =  2,  =  +  23.6    J 

Jungfleisch  and  Leger2  look  upon  this  body  as  a  mixture  of 
several  bases,  Hesse,5  however,  not. 

Diacetyl&pocinchonine,  C^H^  (  C2H8O  )  2N4O2  .     Yellow  varnish- 
like  mass. 

Inactive  in  2  per  cent,  alcoholic  solution. 

3  mol.  HC1  -f  water  ............  c  =  2,     [«]}f  =  -f  26.1°  4 

ISOAPOCINCHONINE,   C19H22N2O.     Anhydrous  prisms  ;  melt- 
ing-point, 223°  to  224°. 

Absolute  alcohol  .......   c  =  3,     [crj^s  =  -f  186.2°  5 

APOISOCINCHONINE,  C19H,2N.2O.     Anhydrous  white  needles  ; 
melting-point,  216°. 

Absolute  alcohol  .......   r  =  3,     [«]$=  +  166.8°  6 

Chlorapoisocinchonine  ,      C19H23C1N2O.      Anhydrous      white 
needles  ;  melting-point,  203°. 

Absolute   alcohol  ......   c  =  3,     [or]$  =  +  189.8° 


Dihydrochloride,   C^H^ClNjO^HCl.      Anhydrous  crystals. 
Water  ............   c  =  3,     [ar]^5  =  +  172.5°  7 

HOMOCINCHONINE,  C19H2,N2O.    Prisms  ;  melting-point,  251  °. 
2  vol.  chloroform  •+•  i  vol.  absolute  alcohol.  .  .  c  =  3,     [«]^f  =  -f  208.9° 

Hydrochloride,  C19H22N2O.HC1  +  2H2O.     Needles. 

Alcohol  (97  vol.  p.  c.)  ...........  ^  =  3,     [«]}?  =  +  159-7° 

Dihydrochlori.de,  C19H22N,O.2HC1.     Prisms. 

Water  .........   £=2.528,     [a]'J  =  -f  198.5°  « 

PSEUDOCINCHONINE,  C^H.^NjO.     Anhydrous  white  needles  > 
melting-point,  252°. 
2  vol.  chloroform  -(-  i  vol.  absolute  alcohol.  ..  c  =  3,     [«"])f   =  -|-  198.4° 

1  Hesse:  Ann.  Chem.  (Uebig),  305,  333. 
*  Compt.  rend.,  114,  1192. 

Ann.  Chem.  (I^iebig),  376,  118. 

Hesse  :  Ibid.,  203,  339- 

Hesse:  Ibid.,  376,  117 

Hesse  :  Ibid.,  376,  100. 

Hesse  :  /*/'</.,  376,  102. 

Hesse:  Ibid.,  376,  104  and  105. 


ALKALOIDS  687 

Dihydrochloride,  C19H,.,NaO.2HCl.     Prisms. 

Water c  ------  3,     [<*]^  =  -f  189.3°  ' 

or-OxYCiNCHONixE,  C,9H22N2O2.     Colorless  flattened  prisms. 

Alcohol  (97  vol.  p. c.) c=?lt     [or]*  =  +  182.56° 

2  mol.  HC1  +  water f=i,     M$  =  -f  210.76 

Hydrochloride,  C,9HMN2O2.HC1.     Colorless  needles  ;  melting- 
point,  230°,  with  decomposition. 

i  mol.  HC1  —  water c=It     [a]g  =  -f  174.37°  * 

/?-OxYCiNCHONiNE,    C19H.,2N.,O.,.      Needles ;    melting-point, 

273°. 

Alcohol    (97vol.  p.  c.) c  =  i,     [«]^  =  +  187.14°  3 

[a\D  =  +  I8S.804 

CINCHOTENINE,  C18HaoN2Os  -f  3H2O(?).     Crystals  ;  melting- 
point,  197°  to  198°. 

Chloroform-alcohol  mixture . .  c  =  2,     [>]}=  =  -f  1 15.5°  -»  5 
2  mol.  H2SO4  -f  water c  =  2,  =  +  175.5    J 

CINCHOTENICINE,    C18H20N2O3.      Dark    brown    amorphous 
mass;  melting-point,  153°  (uncorr.). 

Water c  =  2.614,     M^  =  +  0.9°  6 

CINCHOTENIDINE,  C^H^N.O.,  +  3H2O.    Monoclinic  prisms  ; 
melting-point,  256°  (corr.). 

Water p  —  0.212  [«]/>=    -  189°  7 

3  mol.  HC1  -f  water. . .  c  =  5  (anhydrous),     [tt]g  =    -  201.4°  8 

CINCHONICINE,  CWH22N2O.     Tough  yellowish  mass. 

Alcohol  (95  vol.  p.  c. ) c  =  i,     [<*] 

Chloroform c  =  2, 

1  Hesse  :  Ann.  Chem.  (I,iebig),  276,  107  and  108. 
-  Jungfleisch,  l,£ger  :  Compt.  rend.,  108,  952. 

3  Jungfleisch,  I,€ger  :  Compt.  rend.,  105,  1257  ;  Bull.  soc.  chim.,  49,  747. 

4  Jungfleisch,  I,£ger  :  Compt.  rend.,  119,  1264. 
9  Hesse  :  Ann.  Chem.  (Liebig),  176,  233. 

6  Hesse  :  Ber.  d.  chem.  Ges.,  11,  1983. 

"  Skraup,  Vortmann  :  Ann.  Chem.  (Liebig),  197,  240. 

8  Heese  :  Ber.  d.  chem.  Ges.,  14,  1893  (note). 

»  Hesse  :  Ann.  Chem.  (Liebig),  178,  262. 


688  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Roques  obtained  it  in  crystalline  condition,  and  found  : 

Alcohol [a]/>  =  +  48.25°  P 

2  mol.  HC1  +  water "    s  =  +  28.72    ) 

Oxalate,  (C19H22N,O)2C2H2O4  +  3(?)H2O.     Crystals. 

Alcohol  (97  vol.  p.  c) c  —  2,  [rtr]^s  =  +  23.5°  -j a 

Chloroform-alcohol  mixture  c  =  i  to  3,          "    —  +  23.1 

Water    c  —-  2,  "   =  =  +  22.6 

2  mol.  H2SO4  +  water c  —  2,  "   =  =  +  25.75 

CINCHONIDINE,  C19HMN2O.     Crystals  ;  melting-point,  207.2 
(corr.)  ;3  200°  to  201°  ;*  210.5°." 

Alcohol  (97  vol.  p.  c.) c  —  i  to  5,     [«]^f  —    —  107.48  +  0.297  c 

(95    "       "    ) r  =  2,  "   =  —  113.53  +  0-426  c 

(80    "       "    ) r  =2,  -  119.5 

Chloroform-alcohol    mixture  <:  —  2,  "   =     -108.9 

Chloroform c  =  2,  "    =  83.9 

Absolute  alcohol  c •--    1.5  2  2.5          3  3.5  4 

/  =  15°          -110.0°       109.6°     109.2°     108.8°     108.4°       108.0° 
20  -  109.0        108.6        108.2     107.8      107.4        107.0 

Alcohol  (wt.  p.  c.)  loo.o          90.5      80.2        70.8          60.0 

For    r— 1.54,       [a]1^—    -109.6°         115.0     117.8       120.4        121. i 

Chloroform c=  1.545,     [<*]$  =     -77-3° 

<:  =  3.4i,  -  74.0 

Chloroform-alcohol  mixture...  p  =  i.i  to  2.1,     [a]^-2-18-*0  =     —  107.9°  8 

Chloroform c  —  4,  [a]/?  —      "    70.0° )9 

3  mol.  HC1  +  water £  =  5,  -174.6] 

Hydrochloride,    C19H22N2O.HC1  +  H2O.     Triclinic   crystals. 

Water c  —  i  to  3,     (>]£  =    -  105.34  +  0.76  c 

alkaloid,  -  123.98  +  1.05  c 

Water  +  2  mol.  HC1--  •  c  —  i  to  10,       "    =  —  154.07  +  1.39  c 
alkaloid,         "    =  —  181.32  +  1.925  c 

Alcohol  (97  vol.  p.  c. ) c  =  3,  [<*]}5  =    -  108.0° 

(80    "        "   )  ....   c=  2,  -  135.25 

Chloroform c  =  2.85  (anhydrous),         "    =  24.2 

2  mol.   HC1  +  water c  =  10,  [«]^J —  -- 142.1°  * 

1  Compt.  rend.,  120,  1170. 
*  Hesse  :  Ann.  Chem.  (I^iebig),  178,  263. 
l^enz  :  Ztschr.  anal.  Chem..  27,  565. 
Hesse:  Ber.  d.  chem.  Ges.,  14,  1891. 
Skraup,  Vortmann  :  Ann.  Chem.  (I,iebig),  197,  229. 
Hesse  :  Ibid.,  176,  219. 
Oudemans  :  Ibid.,  i8a,  44. 
I^nz  :  Loc.  cit. 

Hesse:  Ann.  Chem.  (I^iebig),  205,  196. 
>°  Hesse:  Ibid.,  176,  220. 


ALKALOIDS  689 

Salt,  C19H22N2O.HC1  -f  2H2O. 
Water c  =  1.54  to  1.62  (calculated  as  alkaloid),          ")  1 

[a]j7  —    —  104.6°  (anhydrous)  ;  alkaloid,  [<*]$  =    -  129.2° 
Absolute  alcohol c  =  1.54  to  1.62   (calculated  as  alkaloid), 

[or]^  =  —    99-9°  (anhydrous)  ;  alkaloid,  [a]jj  =  —  123.5° 
Alcohol  (89  wt.  p.  c.) . .  c  =  1.54  to  1.62  (calculated  as  alkaloid), 

[a]}]  =  —  119.6°  (anhydrous)  ;  alkaloid,  [a]^  ==  —  147.7° 
Alcohol   (80  wt.  p.  c.)  •  •  c  =  1.54  to  1.62  (calculated  as  alkaloid), 

[tt]1^  =    -  128.7°  (anhydrous)  ;  alkaloid,  [(*]%  =    ~  I59-°° 

Neutral  Sulphate,  (C19H22N2O)2H2SO4  -f-  6H2O.     Glistening 
prisms. 
Water <:  —  1.06,     [orpj  =    -  106.77  ,  alkaloid,  [«]}f  —    -142.31° 

Salt  with  j  Mol.   Water. 

Alcohol   (80  vol.  p.  c.) £=*,     O]^s  =    -  144.5°  2 

Absolute  alcohol c  —  1.54  to  1.62  (calculated  as  alkaloid),          ^  L 

[a]j7  —  -  118.7°  (anhydrous)  ;  alkaloid,  [or]^  =    -  157.5° 
Alcohol  (89  wt.  p.  c.).-  c  =  1.54  to  1.62  (calculated  as  alkaloid), 

[«]£  ==    -  128.7°  (anhydrous)  ;  alkaloid,  [ar]j7  —    -  171.8°  j 
Alcohol  (80  wt.  p.  c. ) . .   c  =  1.54  to  1.62  (calculated  as  alkaloid), 

[or]'/  —  —  131.2°  (anhydrous)  ;  alkaloid,  [«]^  =     -  175.1°  J 


Acid  Sulphate,    C19H2,N2O.H2SO4  +  5H2O.     Large   prisms. 

Water c  =  2,     [a]^  =    -110.5°;  ^i5 

alkaloid,  [a]g  =    -  1 77-95°  I 

Alcohol    (80  vol.  p.  c. ) c  =  2,     [a]^  =    -  109.0° 

Chloroform-alcohol  mixture  r  =  2,  -  101.0 

Disulphate,  C19H,2N2O.2H2SO,  -f  2H2O.     Small  prisms. 
Water,  c=  i  to  7,     [«])=—   —  105.96  —  1.0267 c  —  0.03376  c1  -f  0.00104^") 4 
Alkaloid,  —  185. 77  -f-  3. 1557  c  —  o.  18158  c~  -f  0.00981  r*  f 

Nitrate,  C19H22N2O.HNO:{  +  H2O.     Large  prisms. 
Water <:—  1.54  to  1.62  (calculated  as  alkaloid),          "j1 

[«]^  =      -    99-9°  (anhydrous)  ;  alkaloid,  [a]g  =  —  126.3° 
Absolute  alcohol c=  1.54  to  1.62  (calculated  as  alkaloid), 

[o:]^  =    -  103.2°  (anhydrous)  ;  alkaloid,  [a]1^  =    —  130.4° 
Alcohol  (89  wt.  p.  c.  )• ..  r=  1.54  to  1.62  (calculated  as  alkaloid), 

[a]^7  =    -  119.0°  (anhydrous)  ;  alkaloid,  [a]^  =    -  150.4° 
Alcohol  (80  wt.  p.  c.)...  c=  1.54  to  1.62  (calculated  as  alkaloid), 

[a]1^  =    -  127.0°  (anhydrous)  ;  alkaloid,  [>]$  =    -  160.4°  } 

1  Oudemans :  Ann.  Chem.  (I^ebig),  182,  46. 
'-'  Hesse  :  Ibid.,  176,  221. 

3  Hesse  :  Ibid.,  176,  222. 

4  Hesse  :  I^oc.  cit. 

44 


r  — 2,     [<*]^  =  —  38.4°  ^  5 
c  =  2,        "  —66.6    | 

c  =  2t       "          —81.3  ) 


690  CONSTANTS   OF    ROTATION   OF   ACTIVE    BODIES 

Oxalatc,  (C1!(H2,N,O),C2H.,O4  +  2H2O.     Prisms. 

Chloroform-alcohol  mixture,  c  =  i  to  3,     [a]$  =   —  98.7°  ' 

Oudemans2  has  made  observations  on  the  changes  which 
take  place  in  the  specific  rotation  of  quinine,  quinidine,  cin- 
chonine  and  cinchonidine  in  presence  of  variable  amounts  of 
HC1,  HNO3,  HC1O3,  HC1O4,  H.,SO4,  H3PO4,  HCHO,,  and 
H2C,,O4.  Also  similar  observations  on  quinamine  and  con- 
quinamine.3 

Wyrouboff4  has  published  numerous  observations  on  cinchon- 
idine salts,  which,  on  crystallizing  from  different  solvents,  com- 
bine with  varying  amounts  of  the  latter. 

Acetylcinchonidine,  C1,JH.,,(C,H3O)N2O.  Brittle  mass  ;  melt- 
ing-point, 42°. 

Alcohol  (97  vol.  p.  c.) 

i  mol.  HC1  +  water 

3    "         "    +      "      

Cinchonidine  Sulphonic  Acid,  C19H21N2O.HSO3  +  H,O. 
Needles  ;  melting-point,  225°. 

3  mol.  HC1  +  water c—  2  (anhydrous),     [<*]^  ==  —  I4°°  (i 

/^-CINCHONIDINE,  C19H22N2O.  Crystals  ;  melting-point, 
206°  to  207°. 

3  mol.  HC1  +  water c=  1.25,     |>]^    —  181.4°  7 

Melting-point,  244°. 

Alcohol  (d  —  0.7944) r—   0.5,     [a]=°  -— —  171.5°  * 

y-CiNCHONiDiNE,  C19H22N2O.   Crystals;  melting-point,  238°. 
Alcohol  (<f  — 0.7944).. £—   0.5,     [a]^—  —  164.6°  '•' 

APOCINCHONIDINE,  C19H22N2O.  Thin  plates  ;  melting-point, 
225°  (turns  brown). 

Alcohol  (97  vol.  p.  c.).  c  =  0.8,     [a]^=  — 129.2°  -.  10 

3  mol.  HC1  -f  water. . .  c  =  2  —  i6o.4(from  cinchonidine)  ' 

3     "       "-f      "...  r  — 2,  —160.2  (from    homocin-, 

chonidine) 

Hesse  :  Ann.  Chem.  (l,iebig),  176,  222. 

Ibid.,  182,  51. 

Rec.  trav.  chim.  Pays-Bas.  i,  18. 

Ann.  chim.  phys.,  [7],  i,  5. 

Hesse:  Ann.  Chem.  (Uebig),  205,  319. 

Hesse  :  Ibid.,,  267,  142. 

Hesse  :  Ibid.,  205,  328  (note). 

Neumann  :  Wien  Monatsh.  Chem.,  13,  660. 

Neumann. 

Hesse  :  Ann.  Chem.  (I^iebig),  205,  329. 


ALKALOIDS  691 

Acetylapotinchonidine,  C19H21  ( C,H3O )  N,O.      Crystals. 

Alcohol  (97  vol.  p.  c.) c  =  2,     [«]$=  —  6I.80)1 

3  mol.  HC1  -f  water <~  =  2,         "     =  —  87.9    ) 

Chlorapocmchonidine ,    C19H.,SC1N.,O.     Thin   plates  ;  melting- 
point,  200°. 

3  mol.  HC1  +  water r  =  2,     [<*]$  =  -  142.2°  * 

Left-rotating  in  alcohol  solution,  also. 

Acetylchlorapocinchonidine,    C19H22  ( C.2H3O )  C1N2O.       Prisms ; 
melting-point,  150°. 

3  mol.  HC1 -f  water £=a, 


HOMOCINCHONIDINE.  Skraup,4  also  Claus  and  Weller,5  con- 
sider this  alkaloid  as  identical  with  cinchonidine,  C19H2:!N2O. 
Melting-point,  205°  to  206°. 

Alcohol  (97  vol.  p.  c.) c=2t     [0-]^  = —  109.3°  6 

-107.31  7 

Chloroform 

3  mol.  HC1  -f  water 


c=2,         "  -107.31 

c=4,         "  -    7o.o^ 

f=5,         "     •  =  —  I67.9J 


Hydrochloride,  C^.H.^N.O.HCl  +  H2O.     Rhombic  octahedra. 
2  mol.  HC1  -r  water r  =  10,     [a]2/,  =  —  139.0°  8 

Sulphate,  (C19H.22N2O),.H2SO4  +  6H2O.     Prisms. 
Two  grams  of  the  anhydrous  salt  are  dissolved  in  20  cc.  of 
normal  hydrochloric  acid  and  diluted  to  25  cc.  with  water. 
r  =  8  (anhydrous),     [ar]g  =  -  137.96°  9 


Acetylhomodnchonidine ,    C19H.21(C2H3O)N2O.     Brittle  mass  ; 
melting-point,  42°. 

Alcohol  (97  vol.  p.  c. ) 

i  mol.  HC1  +  water 

3    "         M    +       "    


.   c=2t     [a]g=  -34-0°  )9 

.,=2;  -  .-fc« 

.     ^=2,  "        =  —  72.5     J 


CINCHOLEUPONIC  ACID,  C8H13NO4  -f-  H2O.     Crystals  ;  melt- 


1  Hesse  :  Loc.  cit.,  p.  338. 

-  Hesse  :  Loc.  oil.,  p.  346. 

a  Hesse :  Loc.  cit., p.  353. 

4  Ber.  d.  chem.  Ges.,  13,  Ref.  933. 

5  Ibid.,  14,  1921. 

6  Hesse:    Ibid.,  10,  2156. 

~  Hesse:  Ann.  Chem.  (lyiebig),  205,  203. 

8  Hesse  :  Ber.  d.  chem.  Ges.,  14,  1891. 

9  Hesse  :  Ann.  Chem.  (Uebig),  205,  320. 


692  CONSTANTS   OF   ROTATION   OF   ACTIVE    BODIES 

ing-point,  126°  to  127°  (hydrated);  225°  to  226°  '  (anhydrous), 

221°  to  222°  2  (anhydrous). 
Made  by  oxidation  of  : 

Cinchonine Water,  c  =  4,  [a]£  =  -f  30.00°  ) s 

Chitenine "  c  =  4,  "       =  +  30.25    j 

Cinchonidine "  <r=4,  "       -  +  30.17* 

Quinidine  "  ^—4,  "       =  +  30.9 5 

Hydrochloride,    C8H13NO4.HC1.     Triclinic   prisms  ;  melting- 
point,  193°  to  194°. 
Made  from  : 

Cinchonine Water,  £=4,  *  =  2O°,  [«]/>— -f  37. 75°\3 

Chitenine "       f  =  4,  ^  =  23                   =  +  34.0     j 

Cinchonidine  ...  "        c  =  4,  Y  =  2o                    =  +  40.2* 

Quinidine "       £=4,  t  =  2o                   =  -f  39.6 6 

Cinchonicine  • . .  "        <:—  4,  /—  20                    =  +  35-6|7 

Quinicine "        £—4,  t  =  2o                   =  +  35-6^ 

ARICINE,  C23H,6N2O4.     Crystals  ;  melting-point,  188°. 

Ether  (^=0.72) r^=  1102.5,     [«]^^  -  94-7°i 8 

Alcohol  (97  vol.  p.  c.)  ...  r=i,  —  54.1   -I 

No  rotation  in  hydrochloric  acid  solution. 

CUSCONINE,    C,3H26N2O4  -f-  2H2O.     Crystals;   melting-point, 
110°. 

Ether  0/^0.72)  r=i,     [or]g  =    -  27.1°  ]  9 

r  =  2,        "     =  —  26.8    I 

Alcohol  (97  vol.  p.  c.) r  =  2,        "  —54-3    j 

3  mol.  HC1  -f  water ^0.5,    "  -71.8   J 

CONCUSCONINE,   C23H26N2O4  +  H2O.      Monoclinic  crystals  ; 
melts  at  144°,  then  solidifies  and  melts  again  at  206°  to  208°. 

Alcohol  (97  vol.  p.  c.) c=2,     [>]$= -f  36.8° '" 

r---  2,         "    :  =  +  40.8°  " 

Skraup  :  Monatsh.  Chem.,  10,  46. 

Schniderschitsch  :  Wien.  Monatsh.  Chem.,  10,  60. 

Skraup. 

Schniderschitsch. 

Wiirstl :  Wien.  Monatsh.  Chem.,  10,  70. 

WML 

Skraup,  Wiirstl  :  Wien.  Monatsh.  Chem.,  10,  226. 

Ann.  Chem.  (Uebig),  185,  313. 
Hesse  :    /*/</.,  185,  303  ;  Ber.  d.  chem.  Ges.,  16,  61. 
Hesse  :  Ber.  d.  chem.  Ges.,  16,  61. 
11  Hesse  :  Ann.  Chem.  (Uebig),  325,  236. 


ALKALOIDS  693 

a-Concusconinemethylsulp hate,  (C23H26N2O4.CH3) 2.SO4  (at 
120°).  Amorphous. 

Water c  =  3.764  (anhydrous),     |>]^  =  +  73° 

fi-Concusconinemethylsulphate,      (  C23H26N2O4.  CH3),.  SO4      ( at 

120°). 

A  2  per  cent,  aqueous  solution  was  optically  inactive.1 

QUINAMINE,  C19H24N,O2.     Long  prisms  ;  melting-point,  172°. 

Alcohol  (96  (?)  vol.  p.  c. ) c  —  0.8378,  O]^s  =  +  106.8°  "- 

Alcohol  (97  vol.  p.  c.) c  =  2,  [a~\%  =  +  104.5°  1  3 

i  mol.  HC1  +  water £=2,  =  -}-  116.0     ] 

3     "        "+       "    ^=2,  "    =+117.2    J 

Chloroform c  =  2,  [al^  =  +    93-5°°  * 

Absolute  alcohol £  =  0.502,  [<*]^  =  +  104.6°     5 

"  "        r=i.oi6,  "   =4-103.9 

"        r  =1.494,  ^+102.8 

£=1.774,  .+  100.7 

Alcohol  (90  wt.  p.  c.) £=1.648,  =+101.5 

Absolute  ether c  =  0.458,  =  +  121.4 

14  £=1.024,  =+119.9 

Chloroform £  =  0.722,  =+  94.9 

£=1.512,  =+  94.0 

£=2.235,  "  =  +  93.3 

Benzene £  =  0.056,  =+  99.3 

"  c  =  1.489,  "  =+100.9 

The  influence  of  acids  (HC1,  HNO3,  HC1O3,  HC2H3O,, 
HCHO2,  H2SO4,  H2C2O4,  H3PO4)  on  the  specific  rotation  is 
discussed  in  these  papers. 

Hydrochloride,  C19H24N2O2.HC1  -f  H2O.     Prisms. 

Alcohol  (97  vol.  p.  c.) £  =  2,     [a]£  =  +  118.1°-*  3 

Water £  =  2,  =  +  100.0    } 

Hydrobromide,  C19H24N2O2.HBr  +  H2O.     Prisms. 
Water £  =  4,     OPj  =  +  88.2°  6 

Hydroiodide,  C19H24N2O2.HI.     Crystals. 

Absolute  alcohol £  =  1.068,     [a]^  =  +  92.5°  ^  7 

"      £=1.644,  =  +  94-4 

"      £=2.310,          "   =  +  95-8   ) 

1  Hesse  :  Ann.  Chem.  (I^iebig),  325,  241. 

2  Hesse  :  Ibid.,  166,  2^2. 

3  Hesse  :  Ibid.,  307,  307. 
•»  Hesse  :  Ibid.,  199,  337. 

'•>  Oudemans :  Ibid.,  197,  54  ;  Rec.  trav.  chini.  Pays-Bas,  I,  22  1024. 

G  Hesse  :  Loc.  cit. 

7  Oudemans  :  Ann.  Chem.  (I^iebig),  197,  60. 


694  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Nitrate,  C19H24N2O2.HNO3.     Monoclinic  crystals. 

Water c  =  0.997,     [«]*  =  +    96.8°  ^  l 

"  £=1.934,         =4-  97.0 

Absolute  alcohol c  =  0.9945,        ' '    -  =  +  109. 2 

"       c=  2.036,          "   ==  +  109.6 

Perchlorate,  C19H24N2O2.HC1O4.     Anhydrous  crystals. 

Absolute  alcohol c  =  0.709,       [«]$=+    99-3°  ^ 2 

"       £=2.1335,          "    =+  101.8    f 

QUINAMIDINE,    C19H24N2O2.     Wart-like   bunches ;    melting- 
point,  93°  (not  corr.). 

Alcohol   (97  vol.  p.  c.) c=2,     [a] J§  =  +  4.5°  * 

Hydrochloride,  C19H24N2O2.HC1  +  H2O.     Prisms. 
Inactive  in  2  per  cent,  aqueous  solution.4 

QUINAMICINE,   C19H24N2O2.     Crystals  ;   melting-point,   109° 
(uncorr.). 

Alcohol  (97  vol.  p.  c. ) c  =  2,     [a]  'J  =  +  38.  i  °  )  * 

3  mol.  HC1  +  water c  =  2,  =  +  47.0    / 

APOQUINAMINE,   C19H22N2O(at   100°).      Crystals;  melting- 
point,  114°  (uncorr.). 

Inactive  in  2  per  cent,  alcoholic  solution. 

i.i  mol.  HC1  +  water c  =  2,     [apj  =  —  28.4°  ^* 

3        "        "    +      "     •• 
10        "         "    +      "     .. 


c  =  2,     [a]'j  =   -  28.4°  ^ 
^  =  2,  -29-1 

C=2,  "    =  —  30.0    J 


Acetylapoquinamine,  C19H21(C2H3O)N:!O  (at  100°).  Amor- 
phous. 

Alcohol  (97  vol.  p.  c.) £^=2,     [a]jf  =         o° 

10  mol.  HC1  +  water c  ^=  2,          "    =  —  31.2 

HYDROCINCHONIDINE,  C,9H24N2O,  according  to  Forst  and 
Boehringer,5  is  identical  with  Hesse's  cinchamidine.  Crystals  ; 
melting-point,  229°  ;6  230°. ' 

Alcohol  (97  vol.  p.  c.) c=2,     Mjf  =    —  98.4°  8 

Oudemans  :  Loc.  cit.,  p.  58. 

Oudemans  :  Loc.  cit.,  p.  59. 

Hesse:  Ann.  Chem.  (lyiebig),  207,  307. 

Hesse :  Loc.  cit. 

Her.  d.  chem.  Ges.,  15,  520. 

Forst,  Boehringer. 

Hesse. 

Hesse :  Ber.  d.  chem.  Ges.,  14,  1683. 


ALKALOIDS  695 

The  specific  rotation  is  greater  in  acid  solution. 
On  fusing  the  acid  sulphate,  an  amorphous  modification  of 
hydrocinchonidine  is  formed,  which  melts  below  100°. 

3  mol.    HC1  +  water c  —  2,     [or]^  —    -  12°  ' 

Hydrochloride,  C19H24N2O.HC1  -f-  2H2O.     Prisms. 

Water £=2,     [a]**  =     -    80.4°  ]  2 

"     *  =  5,         "   =  —    66.0    I 

"     f  =  8,  -    60.4 

2  mol.    HC1  +  water £  =  5,  -109.4 

Alcohol    (97  vol.  p.  c.) £  =  5.  -    72-4    J 

Neutral  Sulphate,    (C19H24N2O)2.H2SO4  +  7H2O.     Needles. 

Water c  =  2,     [a]^  =    -  75.2°  -»3 

Alcohol   (97  vol.  p.  c.)..  £=2,  —93-8    j 

Add  Sulphate,  C19H24N,,O.H2SO4  -f-  4H2O.     Prisms. 
Water c  =  4,  .  [«]£  -    -  92-7°  3 

Acetylhydrodnchonidine,      C19H23N2O.C2H3O.       Amorphous; 
melting-point,  42°. 

Alcohol  (97  vol.  p.  c. ) £  =  2,     [a]^  =   -  29.5°  ~)  3 

3  mol.  HC1  —  water r  =  2,     [«]£--   —50.9    j 

CONQUINAMINE,    C19H,4N2O,.     Triclinic   crystals;  melting- 
point,  123°  (corr. ). 

Alcohol  (97  vol.  p.  c. ) c  =  2,  [or]]*  =  +  204.6°  ]  * 

Chloroform c=i,  M-5  J 

I  mol.  HC1  —  water £=2,  =  —  229.1 

3  "        "    +      "     ........   £=2,  =  +  230.0  | 

3     "        "    +      "     c  =  4,  --  +  230.0  J 

Absolute  alcohol c=  0.8025,     [a]«  =  +  205.1°  ^  * 

"  "          £  =  0.8195,  --  —  204.2 

c=  1.531,  203.5 

"  "  £  =  2.7II5,  =+202.6 

£=3.154,  "  =  +  203.0 

"  "  £  =  4.0l8,  =  +  204.1 

£=4.986,  "=-  +  203.5 

Alcohol   (91  wt.  p.  c. ) C=  1.7595,  r  +  2°4.3 

(80  Wt.  p.  C.) £  =  I.8I3,  =  +  205.5 

Absolute  ether £  =  0.7655,  =  +  192.7 

"    £=1.1515,          "         4    190.6 

"    £=1.522,  "    ==-fl88.1 

1  Hesse:  Ann.  Chem.  (Liebig),  314,  i. 

-  Hesse  :  Loc.  cit 
3  Hesse. 

*  Hesse  :  Ann.  Chera.  (I,iebig),  209,  68. 

5  Oudemans  :  Ibid.,  aop,  46  ;  Rec.  trav.  chim.  Pays- Bag,  i,  23  to  25. 


696  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Absolute  ether c  —  1.6155,  [«]g  =  -f  189.0° 

"    £  =  3-052,  =+190.7 

"    c  —  3-0585,  "==+190.5 

"    c=  4.6465,  "      -+190.3 

Chloroform £  =  0.7945,  "    ==+176.1 

^=1.531,  "=+173-8      , 

"        £  =  3.050,  =  +  171.2 

Benzene c  —  0.8955,  "    =  =+  180.1 

"      f=  1.540,  "   ==+179.1 

"      c  =  2.1285,  "   --=  +  178.6 

"      c  =  3.028,  "=  +  178.2 

"      £  =  3-477,  "==  +  178.0 

The  influence  of  different  acids  on  the  specific  rotation  of 
conquinamine  is  discussed  in  the  same  papers. 

Hydrochloride,  C19H24N2O2.HC1.     Octahedral  crystals. 

Water c  =  4,     [«]'j  =  +  205.3°)  2 

Alcohol    (97  vol.  p.  c.) £  =  4,          "    ==  +  206.4  ) 

Hydrobromide,  C19H24N2O2.HBr.     Monoclinic  crystals. 
Absol.  alcohol,  c  =  1.162,       [a]g  =  +  182.7°;  alkaloid,  [a]g=  +  230.0° 
"  "        £=1.9935,          "   =  + 181.0;  "   =-  +  228.1 

Hydroiodide,  C12H24N2O2-HI.     Crystals. 

Absol.  alcohol,  t  =  i.oii,       [<*]g  =  +  162.8°;  alkaloid,  [or]g=  +  229.6° 
^=2.213,  "    =  +  162.2;  "  =  +  229.5 

Nitrate,  C19H2,N2O2.HNO3.     Rhombic  crystals. 
Absol.  alcohol,  c  =  1.2685,     [«]£  =  +  190.0°;  alkaloid,  [«]£=+  228.6 

Chlorate,  C19Ha4N2O2.HClO:r     Monoclinic  needles. 
Absol.  alcohol,  c  —  0.915,       [a]g  =  +  184.0°;  alkaloid,  [«]fj  =  +  234.0° 

Perchlorate,  C19H84N2O2.HC1O4.     Monoclinic  needles. 
Absol.  alcohol,  c  —  0.710,       [or]»«  =  +  175.4°;  alkaloid,  [<*]$--+  231.8° 
£=1.4755,  =+i75.o;          "  "    =  +  231.4 

Formate,  C19H24N2OrCH2O2     Monoclinic  crystals. 

Absol.  alcohol,  c  =  0.884,       [«]£  =  +  195.8°;  alkaloid,  [or] £  =  +  224.7° 
r  -  1.785,  "    ==+193.0;  "  "   =  +  222.6 

Acetate,  C19H24N2O2.C2H4O2.     Tetragonal  crystals. 
Absol.  alcohol,  c  =  0.921,       [or]g  =  +  181.0°;  alkaloid,  [a]g  =  +  215.8° 
"       £  =  0.8395,  =+179.0;  "  -  +  213.5 

1  Oudemans:  Ann.  Chem.  (Uebig),  aop,  46;  Rec.  trav.  chim.   Pays-Bas,  i,  231025. 
8  Hesse :  Ann.  Chem.  (Uebig),  209,  68. 


ALKALOIDS  697 

Oxalate,    C19H24N2O2.C2H2O4  +  3H,O.       Rhombic  crystals; 
melting-point,  about  115°. 

Absol.  alcohol,  c  =  1.0315,     [a]£  =  -f  163.0°;  alkaloid,  O]'J  =  +  200.6° 
"  "        c=i.  525,  "    =+162.6;  "  "    =  +  200.6 

HYDROQUININE,    C20H26N2O2  -f  2H2O.      Crystals  ;    melting- 
point,  172.3°  (corr.). 

Chloroform-alcohol  mixture £=2.49,     [a]$-8—    —  160.25°  ' 

Melting-point,  168°. 

Alcohol  (95  vol.  p.  c. ) c=  2.4,     [<*]£  =  —  142.2° 

In  loo  cc.,  40  cc.  of  normal  HC1 : 

r=2.4,     O]-  =  — 227.1°* 

Neutral  Sulphate,  (C20H26N2O2)2H2SO4  -f-  6  or  8H2O.     Color- 
less needles. 

4  mol.  HC1  +  water c  =  4  (anhydrous),     [a]$  =    —  222.5°  3 

4     "         "    +       "     c  =  4  "  -I93.40)4 

alkaloid,  -  255.9°  j 

^/y     Hydroquinine,     C20H25N2O2(C2H3O) .      Varnish-like 
mass  ;  melting-point,  about  40°. 

3  mol.  HC1  -f  water c  =  3,     [«]g  =   -  73-9°  5 

HYDROQUINICINE,  C20H26N2O2.     Yellowish  varnish. 
3  mol.  HC1  +  water c  =  3,     [«]£  =    -  17°  6 

DICINCHONINE,  C19H22N2O.7  Amorphous  ;  melting-point,  40°. 

Alcohol  (97  vol.  p.  c.) c  =1.516,     [<*]$  = +  91. 7° 

3  mol.  HC1  -j-  water c  =  I,  =  +  80.4° 

Hydrochloride,  C19H22N2O.HC1.     Prisms. 

Water c  =  5,     M£  =  +  58-7°  • 

PARICINE,  C16H18N2O  +  iVaH2O.     Yellow  powder  ;  melting- 
point,  130°.     The  alcoholic  solution  is  inactive.9 

GEISSOSPERMINE,  C19HMN2O2  -h  H2O.     Small  prisms  ;  melt- 
ing-point, 1 60°,  with  decomposition. 
Alcohol  (97  vol.  p.  c.) c=  1.5  (anhydrous),  [a]^  =  —  93.4°  10 

I,enz  :  Ztschr.  anal.  Chem.,  27,  561. 
Hesse  :  Ann.  Chem.  (I^iebig),  341,  259. 
Hesse  :  Ber.  d.  chem.  Ges.,  15,  856. 
Hesse:  Ann.  Chem.  (Liebig),  241,  262. 
Hesse:  Loc.  cit.,  p.  278. 
Hesse  :  Loc.  cit.,  p.  274 
Hesse  :  Ann.  Chem.  (I^iebig),  276,  119. 
Hesse  :  Ibid.,  a»7,  153. 
Hesse  :  Ibid.,  166,  263. 
11  Hesse:  Ber.  d.  chem.  Ges.,  10,  2164.  • 


698  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

CINCHONAMINE,  C19H24N2O.  Glistening  needles  ;  melting- 
point,  184°  to  185°. 

Alcohol  (97  vol.  p.  c.) c=2,     [a]^s  = -f-  121.1°  l 

According  to  Arnaud,2  [<*]/?==  -f-  H7-90  in  alcoholic  solu- 
tion (93  per  cent.).  Melting-point,  195°. 

Neutral  Sulphate,  (C19H24N2O)2.H2SO4.     Prisms. 

Water c  =  2,     [or]'j  =  -f-  36.7° 

"     *=6,          "   =  +  39-8 

1  mol.  H2SO4  +  water.  . .  c  =  2,          "    =  =  -f  39.6 

2  "        "      +      "     ...  c  =  2,          "   =  =  +  35.7* 
i      "        »      +      "...  t  =  3,  =  +  43-S5 

Acid  Sulphate,  C19H24N2O.H2SO4.     Prisms. 

Water f  =  2,     [a]g  =  \  34-9°)  6 

^  =  6,  -  +  37-4   f 

CHAIRAMINE,  C22H26N2O4  -f-  H2O.     Crystals ;  melting-point, 

233°. 

[a~\D  =  about  -f  100°  ' 

CONCHAIRAMINE,  C22H26N2O4  +  H2O  +  C,H6O  (from  alco- 
hol). Prisms;  melting-point,  82°  to  86°  ;  120°  (anhydrous). 
Alcohol  (97  vol.  p.  c.),  c=  2,  (alcohol  and  water-free),  [<*]$  =  +  68.4°  8 

CHAIRAMIDINE,  C22H26N2O4  +  H,O.     Amorphous  ;  melting- 
point,  126°  to  128°. 
Alcohol  (97  vol.  p.  c.) c  =  3  (anhydrous),     [tt]js  =  -f  7.3°  9 

CONCHAIRAMIDINE,  C22H26N2O4  +  H2O.     Crystals  ;  melting- 
point,  114°  to  115°. 
Alcohol  (97  vol.  p.  c. ) c  =  3  (anhydrous),      C^]^  —    ~  60° 

Alkaloids  of  Coca  Leaves 

fl?-EcGONiNE,  C9H15NO3.     Crystals  ;  melting-point,  254°. 
The  constitutional,  formula  of  Einhorn  and  Tahara11  contains 

1  Hesse  :  Ann.  Chem.  (L,iebig),  335,  220. 

2  Compt.  rend.,  93,  593. 
Hesse  :  Loc.  cit.,  p.  224. 

Hesse  :  Ber.  d.  chem.  Ges.,  16,  62. 
Arnaud :  Compt.  rend.,  97,  174. 
Hesse :  Loc.  cit. 
Hesse. 

Hesse  :  Loc.  cit.,  p.  248. 
Hesse  :  Loc.  cit.,  p.  254. 
Hesse  :  Loc.  cit.,  p.  256. 
11  Ber.  d.  chem.  Ges.,  a6,  324. 


ALKALOIDS  699 

three  asymmetric  carbon  atoms    (compare  Einhorn1),   while 
that  of  Merling2  has  four  such  atoms. 

Hydrochloride,  C9H15NO3.HC1.  Monoclinic  hemimorphous 
crystals. 

Water p  =  4.4,     [or]^  =  -  18.2°  :i 

Methyl  Ester,  C9H14NO3.CH3.  Prismatic  crystals;  melting- 
point,  115°. 

Dilute  alcohol p  =  6.22,     [a]^  =  -f  22.5°  )  * 

"          /  =  6.25,  "     =    4-22.4     J 

Isovaleryl-d-Ecgonine   Methyl    Ester  Hydrochloride,    C5H9O 
C9HI3NO3.CHS.HC1.  •  Thin  leaves;  melting-point,  192°. 
Alcohol £=2.01,     [a]-D  =  +  25.4°  5 

Cinnamyl-d-Ecgonine    Methyl    Ester   Hydrochloride,    C9H7O 
C9H13NO3.CH3.HC1.     Needles  ;  melting-point,  186°  to  188°. 
Alcohol c  —  2. 1 1,     [a]9^  =  +  47.4°  6 

Deriva  fives  of  Benzoyl-  d-  Ecgon  in  e 

Methyl  Ester  (^-Cocaine).  Constitution  :  Einhorn,7  two 
asymmetric  C  atoms ;  Einhorn,  Tahara,s  three  asymmetric 
C  atoms,  C5H7N.CH3.CH3.CHO(CO.C6H5)CH2.COOCH3. 


Hydrochloride,  CnH21NO4HCl.     Monoclinic  plates  ;  melting- 
point,  205°. 

Alcohol  (d™  =  0.9353) ^=1.9,     O?£  =  +  39-47°  9 

Ethyl  Ester  Hydrochloride ,  C18H23NO4.HC1  -f  H2O.     Plates  ; 
melting-point,  215°. 

Water c  —  2,        [a] »,  =  +  40° 

Propyl Ester  Hydrochloride,  C19H25NO4.HC1  +  H2O.      Prisms ; 
melting-point,  220°. 

Water c=  2.6,     [«]£=  +  46.2° 

Ber.  d.  chem.  Ges.,  aa,  1495. 

Ibid.,  24,  3116. 

Einhorn,  Marquardt,  Koch  :  Ibid.,  23,  468. 

L,iebermann,  Giesel  :  Ibid.,  23,  926. 

Deckers,  Einhorn  :  Ibid.,  24,  7. 

Deckers,  Einhorn. 

Ber.  d.  chem.  Ges.,  21,  3029. 

Ibid.,  26,  324. 

Einhorn,  Marquardt  :  Ibid.,  33,  468. 


yoo 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Butyl  Ester  Hydrochloride,  C^H^NO^HCl  -f  H,O.  Fine 
matted  needles  ;  melting-point,  201°. 

Water c  =  2.5,     [a] -,=  +  46° 

Amyl  Ester  Hydrochloride,  C21HWNO4.HC1.  Fine  matted 
needles;  melting-point,  217°. 

Water C=  2.2,     [a]],  =  -f  38.6°  ! 

/-EcooNiNE  HYDROCHLORIDE,  C9H15NO3.HC1.  Triclinic 
plates  ;  melting-point,  246°. 

Water [a]/,  -    -  57°  2 

Cinnamyl-l-ecgonine  Methyl  Ester,  C9H.O.C9H13NO3.CH,. 
Crystals  ;  melting-point,  121°. 

Chloroform c  —  10,     [a]g  =    -  4.7°  :! 

Hydrochloride,  C19H23NO4.HC1  +  2H2O.  Crystals  ;  melting- 
point,  176°. 

Water r  =  66  (anhydrous),     [apj  =    -  104.1°  * 

Benzoyl-l-ecgonine  Methyl  Ester  (/-Cocaine  ordinary 
cocaine) ,  C5H7N. CH3. CHO ( CO.  C6H5)  CH2.  COOCHS.  Mono- 
clinic  prisms  ;  melting-point,  98°. 

Chloroform   p  =  10  to  20,     [tf]^  =   -  16.412  +  0.00585  />, 

from  the  following  observations  : 


MS; 

p. 

rf- 

Found. 

Calculated. 

9-925 

1.4480 

-  16.356 

-16.354 

25.484 

1.3971 

—  16.280 

-16.263 

15.643 

1.4293 

-16.319 

-  16.320 

18.793 

1.4190 

-16.299 

—  16.302 

20.242 

1.4126 

—  16.283 

-16.293      J 

The  specific  rotation  is,  therefore,  almost  constant. 

Hydrochloride,    C17H21NO4.HC1.       Crystals;    melting-point, 
181.5°.*     Five  preparations  from  different  factories,  when  dis- 


Kinhorn,  Marquardt  :  Ber.  d.  chem.  Ges.,  a3,  986-988. 

Einhorn  :  Ibid.,  aa,  1495. 

Hesse  :  Ann.  Chem.  (lyiebig),  371,  185. 

Hesse :  I<oc.  cit. 

Antrick  :  Ber.  d.  chem.  Ges.,  ao,  321. 

Antrick. 


ALKALOIDS  7OI 

solved  in  alcohol  (d™  =  0.9353  —  40  per  cent,  weight) ,  showed 
specific  rotations  at  t  —  20°,  and  for  concentrations  between 
c  =  5  and  25  which  may  be  expressed  by  the  following 
formulas : 

Preparation      I      m.  p.   181.5°,      [<*]£=    —67.904-^0.15654    f 

II          "       182.5,  -68.023  —  0.15898    c 

"  HI          "       185,  —  69.769  -f  0.174407  c 

IV          "      184,  "    --     -67.951  +0.15458    c 

V          "      181.5  "=  —  68.052  +  0.163        c 

from  which,  in  the  mean, 

[a]~  =  -  67.982  +  0.15827  c  l 

On  the  polarimetric  determination  of  cocaine,  see  §186,  p.  501. 

Isatropyl  Cocaine,  C19H23NO4  (at  45°).     Amorphous. 
Alcohol c  =  4,     [<*]y]  =   —  29-3°  2 

ANHYDROECGONINE   is  formed   from   d-    as   well   as    from 
/-ecgonine. 

Hydrochloride,  C9H1SNO,.HC1  +  H.,O.     Rhombic  hemimor- 
phous  crystals  ;  melting-point,  240°  to  241°. 

Water [«]/>  =    -  61.5°  8 

Melting-point,  238°  to  240°. 

Water,  c  =  3   (anhydrous) . .   [<*]^f  =    —  62.7°  4 

/-EcGONiNic   ACID,    C.HnNO3.       From   d-  and  /-ecgonine. 
Crystals;  melting-point,  117°. 

Water c  =  12.37,      [or]],  =   —  43.2°  5 

^-TROPINIC  ACID,    C6HHN(COOH)2.       Crystals;    melting- 
point,  247°  to  248°. 

Water p  =  11.76,     </=  1.036,     [ nr] ],-—-•-  14.8°  6 

Alkaloids  of  Opium 

MORPHINE,    C17H17(OH).,NO  -f-  H2O.     Small  rhombic  col- 
umns. 

1  Antrick  :  Ber.  d.  chem.  Ges.,  20,  310. 

2  lyiebermann :  Ibid.,  21,  2342. 

3  Einhorn  :  Ibid.,  22,  1495. 

4  Hesse:  Ann.  Chem.  (L,iebig),  371,  180. 

5  Iyiebermann  :  Ber.  d.  chem.  Ges.,  24,  612. 

6  lyiebermann,  p.  611. 


702  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

i  mol.  alkaloid  -f  i  mol.  Na.,O c  =  2,  [a]~-s  =   —  67.5°  ~\ l 

i     "            "       -f  5     "         "     c  =  2,  -70.2 

i     "            "       +2     "         "     f  =  5.  -71.0    J 

Absolute  alcohol c  —  i.oo  to  1.80,  [«]^—    -  140.5°  2 

Hydrochloride,  C17H19NO3.HC1  +  3H,O.     Crystals. 

Water r  =  i  to  4,     [or]^  -    —  100.67  +  1.14  f\ 5 

10  mol.  HC1  -f  water c  =  2,  "   =  94-3°  j 


Sulphate,  (C^H^NO.XH.SO,  +  5H2O.     Crystals. 

Water  ............   r  =  i  to  4,     [a]$  =  —  100.47  +  0-96  r  3 

Acetate,  C17H19NO3.C2H4O,  -f  3H8O.  Crystals. 

Absolute  alcohol  ..........   c=i.2,  [<*]/>  =    -100.4°]* 

Alcohol  (d  =  0.865)  .......  ^  =  0-97,         "  -    98.9 

Water  ....................   ^=2.5,  "  77 

"     ....................   r  =•  0.996,       "     =  —    72 

The  effect  of  acids  (HC1,  HNO3,  HCHO,,  HC2H3O,,  H2SO0 
H,C,O4,  H3PO4,  H,AsO4,  C6H8O.)  on  the  rotation  of  morphine 
has  been  investigated  by  Tykociner.5 

CODEINE  (Morphine  methyl  ether),  C17H17(OCH3)(OH)NO 
-f-  H2O.  Rhombic  crystals  ;  melting-point,  155°  ;(1  153°.  ~ 

Alcohol  (97  vol.    p.  c.  )  c  =  2  to  8,     [a]^f  -    —  135.8°  ~\  8 

"  (80      "         "     )    C=2t  -  137.8     | 

Chloroform  ...........  ^=2,  "   =     —  111.5    J 

Absolute  alcohol  ............   c  =  2.32  (anhydrous),  [a~\™  =  —  134.3°)  * 

"       ............   ^=2.97  "    =     -141.1   j 

Alcohol  ....................   £1=4.1,     [<x~\D  —    —  130.34°)  9 

Commercial  codeine,  alcohol,  c  =  4.1  "   =     -  133.18°} 

Hydrochloride,  C^H^NO^HCl  +  2H,O.     Short  needles. 
Water  ......................  c  =  2,     [or]^-s  =  —  108.2°  ")  s 

10  mol.    HC1  -f  water  .......  c  =  2,  "   =   -105.2 

Alcohol    (80  vol.  p.  c.  )  ......  £—2,  "   =  —  108 


:  Ann.  Chem.  (l,iebig),  176,  190. 
Tykociner  :  Rec.  trav.  chim.  Pays-  Has,  i.  147. 
Hesse  :  Loc.  cii. 

Oudemans:  Ann.  Chem.  (I.iebig),  166,  77. 
Loc  .  cit. 

Hesse  :  Ann.  Chem.  (Uebig),  333,  210. 
Grimaux  :  Compt  rend..  93,  1228. 
Hesse  :  Ann.  Chem.  (Uebig),  176,  191. 
Grimnux  :  I.»c.  cit. 


ALKALOIDS  703 

Sulphate,    (C,8H21NO3)2.H2SO4  +  5H.,O.     Rhombic   prisms. 

Water c  =  3,     [<*]^f  —    —  101.2° 

"     c  -—  3,     [»]/?        -100.9 

The  influence  of  acids  on  the  specific  rotation  of  codeine  has 
been  investigated  by  Tykociner  ;2  in  the  neutral  salts,  [<*]!?  = 
about  —  134°  (compare  morphine). 

Methylcodeine Sulphate,  (Cl7H18(CHs)NO3.CH3)2SO4-f-  4H2O. 
Rhombic  crystals. 

Water c  —  5  (hydrated),     [orj's  =    -  130.1°  3 

Methocodeine  (Morphine  dimethyl  ester),  C17Hn(OCH3)2. 
NO.  Crystals;  melting-point,  118.5°. 

Alcohol   (97  vol.  p.  c. ) c  =  4,     Mg  —    -  208.6°  * 

a- Methocodeine  (ar-Methylmorphimethine).  Melting-point, 
118.5°. 

Ether £=2.13,       [<*]$=    -^212° 

Methiodide.     Melting-point,  245°. 

Alcohol ^=1.4,        [<*]$  =  —94-56° 

Acetyl  Derivative.     Melting-point,  66°. 

Alcohol c=  2.698,     [a]/,  =    -96-3° 

Acetyl  Methiodide.     Melting-point,  207°. 

Alcohol c  =  0.586,     [a\D=    -73-87° 

fi-Methylmorphimethine  (does  not  crystallize). 

Ether c=  3-746,     [a]^  =  +  437.3° 

Methiodide.     Melting-point,  297°. 

Alcohol c  —  1.248,     \a\D  =  +  227.45° 

Acetyl  Derivative  (does  not  crystallize). 

Alcohol c=  0.798,     \O\D  ~  +  4I3-90 

Acetyl  Methiodide.     Amorphous. 

Alcohol c  —  0.59,       \_a]D  =  +  257.6°  5 

PSEUDOCODEINE,  C18H21NO3  +  H,O.  Needles  ;  melting- 
point,  178°  to  1 80°. 

Alcohol /=i.9i,     [a]D  =    -91. i°6 

1  Hesse  :  Loc.  cit. 

-  Loc.  cit. 

3  Hesse  :  Ann  Chem.  (I^iebig).  333,  215. 

*  Hesse  :  Loc.  cit..  p.  21 S. 

5  Knorr  :  Her.  d.  chem.  Ges.,  37,  1144. 
c  Merck  :  Arch.  Pharm.,  329,  161. 


704  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

THEBAINE,    C17H15NO(OCH3)2.      Crystals ;    melting-point, 

103°. 

Alcohol  (97  vol.  p.  c.) c  =  2,     [or]^    =      -  218.6°  -|  l 

(97    "       "    ) <~=2,     [a]£    =  —  215.5 

(97    "       M    ) *=l,     Ote'5  =    -216.4 

Chloroform  ^  =  5,         "  -229.5 

Hydrochloride,  C19H21NO3.HC1  +  H.,O.     Rhombic  prisms. 
Water c  =  2  to  4,     [a]£   =   -  168.32  -f-  2.33  c  i  - 

"     ^=2,  O]~-5=- 163.25 

10  mol.  HC1  -f  water c  =  2,  -  158.6° 

PSEUDOMORPHINE  (Oxydimorphine,  Dehydromorphine). 

Hydrochloride,  C34H:J6N2O6.HC1  +  H2O.:$ 

i  mol.  HC1  +  water c  =  0.8 to  1.6,   [a]^-s  =— 114.76 -f  4.96^* 

5»/2  mol.  Na2O  +  water c  =  2,  "  -198.9°  J 

C17H17NO3.HC1  (at  100°)  : 

p  =  cr.95i,         rf^  =  1.0044,        l>]^  =  —  103.13°  5 

LAUDANINE,  C20H.,4NO4.     Rhombic  crystals  ;  melting-point, 

166°. 

Chloroform c  —-.  2,  [«]^'5  =    -  i3-5°\ 6 

2  mol.  Na-jO  -j-  water ^  =  i,  —  11.4  j 

Chloroform ^  =  3-°35  [  a]/>  —  H~     °-°57° 

This  number  lies  within  the  limits  of  experimental  error, 
and  Goldschmidt,7  therefore,  considers  laudanine  inactive. 

Hydrochloride,  CWH25NO4.HC1  +  6H2O.     Inactive/ 
LAUDANIDINE,  C17H15N(OH)(OCH3)3.   Melting-point,  177°. 

[a]D  =  —  87.8°  9  ' 

LAUDANOSINE,  C21H27NO4.     Crystals  ;  melting-point,  89°. 

Alcohol  (97  vol.  p.  c. ) c  =  2.79,     [tfJ'J    :  =  +  103.2° 

"      (97    (<       "    ) c       2,          [<*]%*     -=  +  105.0 

Chloroform c       2,  "        =  +    56.0 

2  mol.    HC1  +  water c       i,  ^  +  108.4    J 

Hesse  :  Ann.  Chem.  (l,iebig),  176,  196. 
Hesse :  Loc.  «'/.,  p.  197. 
Hesse:  Ann.  Chem.  (I^iebig),  335,  229. 
Hesse  :  Ibid.,  176,  195. 
Donath  :  J.  prakt.  Chem.,  [a],  33,  562. 
Hesse  :  Ann.  Chem.  (I,iebig),  176,  201. 
Wiener  Monatsh.  Chem.,  13,  693. 
Hesse  :  Loc.  i  it. 

Hesse  :  Ann.  Chem.  (Uebig),  a8a,  208. 
»"  Hesse :  Ibid.,  176,  202. 


ALKALOIDS  705 

PAPAVERINE,  C20H,MNO4.  Triclinic  prisms;  melting-point, 
147°.  The  earlier  figures  of  Hesse1 

Alcohol  (97  vol.  p.  c. ) i-  :••-.:  2,     [or]  '*        —  4.0° 

Chloroform c  =  2.          "    =  —  5.7 

are  wrong,  according  to  Goldschmidt  ;-'  the  papaverine  formula 
contains  no  asymmetric  carbon  atoms,  in  consequence  of  which 
the  alkaloid  must  be  inactive,  as  Hesse  gives  for  the  hydrochlo- 
ride.  Goldschmidt  found  : 

Chloroform c  =  17.8,     [or]#  =  -f-  0.11° 

Tetrahydropapaverine,  C20H.,.NO4.  The  dextro  and  levo 
bases  have  been  obtained  by  Pope  and  Peachey3  by  resolution 
of  the  racemic  compound  by  dextro- o'-bromocamphorsulphonic 

acid. 

/-Base r  =  4.0032,     [<*]/>=    -143.4° 

rf-Base ^=4-3376>     [«]       =  +  153-7 

Because  of  difficulties  in  the  purification  of  the  separated 
bases,  the  rotations  are  probably  not  quite  accurate. 

CRYPTOPINE,  C21H23NO5.  Crystals;  melting-point,  217°. 
The  alkaloid  is  inactive,  dissolved  in  chloroform  or  hydrochlo- 
ric acid.4 

NARCOTINE  (Opianine),  C,,H.,3NO7.  Crystals;  melting-point, 
176°. 

Alcohol    (97  vol.  p.  c.) c  =  0.74,     [a]«-s :      -  185.0°  ^ 5 

Chloroform   mixture c  =  2,  —191.5 

Chloroform c  =  2  to  5,        "  -207.35 

2  mol.   HC1  -j-  vrater c  =  2,  =  +    47-° 

2     "         "     +      "     ^  =  5,  =+    46.4 

10       "  "       -f         "      C  =  2,  =  -f      50.0 

Alcohol  (80  vol.  p.  c.)  +  2  mol.  HC1-.  c  =  2,  =  +  145.5 

Benzene,  p  =  1.59,     [«]/>  =    -  229°  ;    dilute  oxalic  acid,  [or]/?  =-f6206 

PSEUDONARCEINE,  C23H27NO8.+3H2O.  Crystals  ;  melting- 
point,  about  175°.  Is  inactive  in  acetic  acid  solution.7 

Narceine,  inactive  in  neutral  or  acid  solution.8 

Ann.  Chem.  (Liebig),  176,  198. 

Wiener  Monatsh.  Chem.,  13,  691. 

J.  Chem.  Soc.,  73,  893. 

Hesse  :  Ann.  Chem.  (L,iebig),  176,  200. 

Hesse  :  Ibid.,  176,  192. 

Dott  :  Ber.  d.  chem.  Ges.,  17,  Ref.  77. 
'  Roser  :  Ann.  Chem.  (I,iebig),  347,  169. 
*  Hesse  :  Ibid.,  176,  198. 
45 


706  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

Strychnos  Alkaloids 

STRYCHNINE,  C21H22N2O._,.  Rhombic  columns  ;  melting- 
point,  284°. 

Alcohol  (d  =  0.865)  .....  £  =  0.91,  [CK]D=   -128°  I1 

Chloroform  .............  c  =  4,  -  130 

.............  ^=2.25,  "    =—137.7' 

.............  c=  1.5,  —  140.7 

Amyl  alcohol  ............  c  =  0.53  "    =  —  235 

Alcohol  (d  =  0.8543)....  r  =  0.25,  [«]*>  =    -  114.7°)  2 

"       (</  =  0.8543)  ----  r  =  o.io,  "    =  —  119.3  ) 

Other  constants  are  given  by  WyroubofF  on  strychnine, 
strychnine  sulphate,  and  selenate,  but  without  statement  as 
to  /,  c  or  t. 

The  effect  of  acids  (HC1,  HCHO2,  HC2H3O,>  H2SO4,  H2CrOt, 
H3PO4,  H3AsO4,  H3C6H5O7)  on  the  specific  rotation  of  strych- 
nine was  investigated  by  Tykociner.4 

Desoxystrychnine  Hydrochloride,  C21H26N2O.HC1  (at  100°). 
Crystals. 

Water  ............   c  =  10,     \_a]D  =  -  16.0°  5 

BRUCINE,  C23H26N2O4  -f  4H2O.  Monoclinic  crystals;  melt- 
ing-point, 178°. 

Alcohol  (d  =  0.865)  ........  c  =  5.4,     (anhydrous),  [<*]/>=      -    85°  i  6 

Chloroform  ................   £=1.9,               "  "     =  —  127    j- 

................  ^  =  4-9,  "           -  H9  J 

Absolute  alcohol  ............   £=2.129,           "  M/?  -=    -8o.i07 

Effect  of  acids,  see  under  strychnine/ 


Oxyethylbrudne      Chloride,       C23H26NO4.  N<'  CHa<  OH 


Colorless,  columnar  crystals;;  melting-point,  185°. 
Water  ............  £  =  4-5,     M 

Oudemans  :  Ann.  Chera.  (lyiebig),  166,  76. 

Tykociner:  Rec.  trav.  chim.  Pays-Bas,  i,  146. 

Compt.  rend.,  115,  832. 

Loc.  cil. 

Tafel  :  Ann.  Chem.  (I^iebig),  a68,  245. 

Oudemans  :  Ibid.,  166,  69. 

Tykociner:  Rec.  trav.  chim.  Pays-Has,  i,   148. 

Tykociner  :  Loc.  cit. 

MeulenhofT:  Centrbl.,  1893,  II,  761. 


ALKALOIDS  707 

Other  Alkaloids  and  Bases 

CORYDALINE,  C22H2.NO4.  From  Corydalis  cava.  Crystals  ; 
melting-point,  134°. 

Chloroform c  =  6.55,     [a]^  —  + 300.1°  J 

BULBOCAPNINE,  C19H19NO4.  From  Corydalis  cava.  Mono- 
clinic  columns  ;  melting-point,  199°. 

Chloroform c  —  4.48,     [a] £  =  -f-  237.  i  °  - 

CYTISINE  (Ulexine,  Sophorine),  CUHUN2O.  Colorless 
crystals;  melting-point,  150°  to  151.5°  (uncorr.). 

Water c  =  2,     [a]%  =    -120°     i3 

Alcohol  (90  vol.  p.  c.) c=z,  —  100.42  | 

Chloroform c  —  2,  -    65 .42  J 

Nitrate,  CUH16N2O.  NO3H  +  H2O.     Crystals. 

Water c  =  5,         M£  =  -  90.1?°)  * 

"     c=2.5  -89.33   i 

DELPHININE,  C22H35NO6  (at  100°).     Rhombic  crystals. 
DELPHINOIDINE,     C^H^NjO,.       Crystals ;     melting-point, 

110°  tO   120°. 

STAPHISAGRINE,  C22H33NO5.     Amorphous. 

The  last  three  alkaloids  are  inactive  in  alcoholic  solution.5 

ECHITAMINE,  C22H28N2O4  +  4H2O.     Crystals. 

Alcohol  (97  vol.  p.  c.) -  c  —  2,     [ar]^f  =   -288° 

According  to  Hesse,6  it  is  identical  with  Harnack's  ditaine.7 

IMPERI ALINE,  C^H^NO^?).     Needles  ;  melting-point,  254°. 
Chloroform p  =  5.262,     [<*]/>=    —  35-4°  8 

PILOCARPINE,  C23H34N4O4  -f  4H2O.  Tough  colorless  mass. 
(Solvent?)  c  =  7.24,  [«]/>  =  -f  101.6°  ;  r  =  25.89,  [_a]D  —  +  87.77°  9 

A  review  of  recent  determinations  on  pilocarpine  is  given  by 
Jowett,10  and  the  optical  rotation  of  the  base  and  salts  has  been 
measured.  The  formula  of  the  base  is  taken  as  CUH16O2N2. 

Freund,  Josephi :  Ann.  Chem.  (I^iebig),  277,  7. 

Freund,  Josephi  :  Ibid.,  277,  12. 

van  de  Moer  :  Arch.  d.  Pharra.,  229,  57. 

van  de  Moer  :  Loc.  cit. 

Marquis  :  Jahresbericht,  1877,  p.  896. 

Ann.  Chem.  (I,iebig),  203,  144- 

Ber.  d.  chem.  Ges.,  u,  2004. 
8  Fragner  :  Ibid.,  21,  3284. 
»  Poehl :  Jahresbericht,  1880,  p.  993,  1075. 
10  J.  Chem.  Soc.,  77,  473- 


708  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


For  the  salts,  the  solvent  used  appears  to  be  alcohol  or  water. 

Nitrate,  CnH16O2N2.HNO3,  £=9.572,  \ci\n  =  +  82.90° 

Hydrochloride,  c—   9.924,  =  +  91.74° 

Hydrobromide,  c  =  10.058,  =  +  77.05° 

Sulphate,  c  =    7.318,  ^  +  84.72° 

ISOPILOCARPINE,  CHH1$N2O2. 

Base £=11.652,  [<*]/>  =  +  42.91°  1 J 

Nitrate £=    6.586,          "   =  +  35.68    | 

Hydrochloride c=    4.974,  [or]       =  +  38.8 

Hydrobromide c=    2.288,  "         -  +  32.8     J 

PlLOCARPIDINE,  C10H14O2N2. 


Base  ................  ^=1-5374, 

Nitrate  .............  £= 


1-5374,     [«]/>  =  +  81.3°  "I2 
7.104,  =  +  73-2     \ 


PiPERiNE.     Inactive. 

SPARTEINE.  C15H26N2.  Thick  oil,  colorless  and  odorless, 
Boiling-point,  180°  to  181°  (20  mm.). 

Alcohol  (96  p.  (:.)•••••  .....   r=23.88,       [a]g  =    -  14.6°  3 

^-«-PiPECOLiNE  (or-Methylpiperidine),  C.H10N.CH3.  By 
resolution  of  the  racemic  synthetic  a-pipecoline  by  means  of 
rf-tartaric  acid.  Boiling-point,  118°  to  ngV 

do  =  0.860,    [a\D  =  +  21.73°  5 
Purest  preparation  :  [«]/>  =  -f  37-29  \  36-9  ',  37-2°  6 


(</-a'-jV-Propylpiperidine),  C5H10N.C3H7. 
i.  Natural  Conine.     From  Conium  maculatum. 

d*  =  0.873,  [or]/,  =  +  15.6°  ' 

d?  =  0.845,  [«]/>  =  -f  13-79  8 

d    i=  0.845,  b.  p.  166°  to  167°,     \_a]D  is  +  15.6°  9 

^•  =  0.8438,  b.  p.  165.710  165.9  (759  mm-).  O]#  -  +  15-7°  1(> 

Jowett  :  Loc.  cit.     Solvent  not  given. 

Jowett  :  Loc.  cit.     Solvent  not  clearly  given. 

Bernheimet  :  (ia/.z.  chini.  ital.,  13,  451. 

I^uletiliurg  :  Ann.  Chem.  (lyiebig),  347,  65. 

I^adenburg  :  Loc.  cit.  (1888). 

I«adenburg  ;  Her.  d.  chem.  Ges.,  37,  856,  3063  (1894). 

H.  Schiff:  Ann.  Chem.  (Uebig),  166,  94  (1873). 

I^adenburg:  Ibid.,  347,  86  (1888). 

I,.id<  nburg  :  Ber.  d.  chem.  Ges.,  37,  858  (1894). 

Wolffenstein  :  /hid.,  37,  2612. 


ALKALOIDS 


709 


2.  Artificial  Conine,  by  resolution  of  or-A^-propylpiperidine  by 
means  of  </-tartaric  acid.1 

d™  =  0.845,     O]/>  =  -f  13-87°  2 

rf«  ==  0.8438,  b.  p.  167.7°,    [>]/>  =  +  18.3°  ' 

The  following  data  on  the  specific  rotation  of  conine  and  its 
salts  are  given  by  Zecchini.* 


Name. 

Solvent. 

c. 

/. 

M*.  ' 

Conine 

Benzene 

13.094 

24.2° 

+  9-54° 

11 

20.464 

22.1 

+  9-77 

" 

" 

33-29° 

23-9 

+  11.14 

11 

Alcohol 

10.841 

24.4 

-f     8.12 

1  1 

<  i 

15.172 

22.7 

+   8.70 

" 

44.687 

26 

+  9-98 

<  < 

Water 

1.071 

25-7 

+     I.2I 

Acetate 

Benzene         22.854 

25-7 

+     3.63 

" 

Alcohol         21.904 

25.0 

-f   2-35 

.< 

Water          31-944 

26.6 

-|-    1.16 

Hydrochloride 

Alcohol           6.722 

25 

+   4.56 

(  4 

Water 

11.458 

26 

+  0.27 

Hvdrobromide 

Alcohol 

6.053 

23-4 

-f   4.28 

1 

Water 

11.890         25.6 

-j-   0.27 

Acetylconine,  C8HltN(C8H8O).     Liquid;   boiling-point,  125° 

(14  mm.). 

rf16  =  0.9616,    [«]*  =  +  34-2°  9 

Benzoylconine,  CSH16N(COC6H5),     Liquid. 
^  =  1.0623,     [a]g=  +  29.i°« 

I-  Conine.     Liquid. 

Absolute  alcohol  ......   c  =  50,     [a]*>  =  +  15.2°  7 

N-Methylconine,  C8H16(CH3)N.     Boiling-point,  173°  to  174' 

(757mm.). 

rf2*-3  =  0.8318,    t  =  24°,    [a]z>  =  +  81.33°  8 

ISOCONINE  (?),  C8H17N. 


Ladenburg:  See  §  33,  p.  112. 

Ladenburg:  Ann.  Chem.  (I^iebig),  247,  86  (1888). 

Ladenburg  :  Ber.  d.  chem.  Ges.,  37,  3066  (1894). 

Esperienze  sul  potere  rotatorio  della  coniina  e  dei  suvi  sali.     Roma,  1893. 

I^adenburg  :  Ber.  d.  chem.  Ges.,  26,  854- 

I^adenburg  :  Loc.  cit. 

I^denburg:  Ann.  Chem.  (Uebig),  247,  86. 

Wolffensteiti  :  Ber.  d.  chem.  Ges..  27,  2611. 

I^adenburg  :  Ibid.,  26,  854. 


710  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

According  to  Wolff enstein,1  this  is  a  mixture  of  ^/-conine 
with  inactive  conine. 

Benzoylisoconine,  C8H]6N(COC6H5).     Liquid. 
</16  =  1.0623,      M/>  =  +  29.1°  - 

/S-PROPYL  PIPERIDINE,   C5H10N.C3H..     The  synthetic  base 
has  been  resolved  by  means  of  tartaricacid  by  J.  D.  Granger.3 
d-Base,  d  —  0.8517,     |>]£  =  -f  6.39° 
I -Base,  d  =  0.8517,  -  6.39° 

a-IsoBUT YLPIPERIDINE  (Homoconine),  C5H10N.CH2. 
CH(CH3)r  Liquid  ;  boiling-point,  i8i°to  182°  ;  d\  =  0.8583. 
Inactive.* 

Homoconic  Acid,  C^H17NO2,  and  Amido  Valeric  Acid, 
C5HnNO2,  formed  by  the  oxidation  of  conine,  are  inactive  in 
5  per  cent,  solution.5 

PARACONINE,  C8H15N.  Liquid  ;  boiling-point,  168°  to  170°. 
Inactive.6 


E,  C8H15N.     Liquid  ;  boiling-point,  168°. 
d*i  =  0.8976,    [a]/,  =    -  7.8°  T 

£-CONICEINE,  C8H15N.     Liquid  ;  boiling-point,  150°  to  151°. 
[a]/?  =  about  -f  42°  s 

The  statement  of  Hesekiel9  that  /?-picoline  is  active  is  an 
error,  according  to  Landolt.10 

NICOTINE,    C10HUN.,.       Boiling-point,    246.7     (745    mm.). 
d™  -  -  i.oiioi. 

-  164.0  '- 

O]g  =  —  161.09  13 
[a]™  =    -  162.84, 

Ber.  d.  chem.  Ges.,  39,  1956. 

leaden  burg:  Loc.  cit. 

Ber.  d.  chem.  Ges.,  30,  1060. 

Jacobi,  Stoehr  :  Ibid.,  a6,  949. 

Schotten  :  Ibid.,  19,  503,  507. 

Michael  :  Ibid.,  14,  2105. 

I.t-llmann  :  Ann.  Chem.  (Uebig),  359,  199. 

I«ellmaiin,  p.  203. 

Ber.  d.  chem.  Ges.,  18,  3091. 

Ibid..  19,  157. 

"  Mndolt,  §52:  Ann.  Chem.  (Uebig),  189.  241. 
11  Hein  :  Inaug.  Diss.,  Berlin,  1896. 
13  N.-isini  and  Pezzolato  :  Ztschr.  phys.  Chem.,   12,  501. 
M  Gennari  :  Ibid.,  19,  130,  §  46. 


ALKALOIDS  yil 

Rotation  dispersion  of  nicotine.1 

Effect  of  temperature  between  10°  and  30 °.2 

Solutions  in  water.3 

Solutions  in  water,  great  dilution.4 

Solutions  in  water,  increase  of  rotation  on  standing.3 

Solutions  in  ethyl  alcohol.6 

Solutions  in  propyl  alcohol,  ether,  acetone.7 

Solutions  in  benzene/ 

NICOTINE  SALTS.     Right-rotating. 

Hydrochloride,  C10H14X,.HC1. 

Water,  [a]^  =  -f-  51.50  —  0.7931  q  —  0.004238  q',  for  q  —  57  to  90, 
from  which  for 

p  =  10  :  [a]»°  =  -  14.44  ;    p  =  3p:  [a]~  ==  +  16.75°  9 

Neutral  Sulphate,   (C10H14N,)2.H2SO4. 

Water,    [a]£  =  —  19.77  —  0.05911  q,     for  q  •=  30  to  90, 
from  which  for 

p'=  10  :  [or]-  =  +  14-52  ;    p  =  30  :  [«]£  -    -  15.64°  lft 

/4«/afc,  C10HMN2.C2H4<X 

Water,   [«]=£  =  —  49.680  —  0.6189  ^  4-  0.002542  ^2,  for  q  =  77  to  95, 
from  which  for 

/>  =  10 :  [or]»  =  +  14.57°  ;  /  =  30  :  [or]»  =  -  18.81°  10 
Water M£  =  +  13.204  —  0.11406  c  —  0.002073  <?,  to  c  =  65  u 

On  the  behavior  of  a  left-rotating  equimolecular  mixture  of 
nicotine  and  glacial  acetic  acid  on  dilution  with  water,  see 
§46,  p.  161.  For  solutions  of  nicotine  acetate  in  alcohol : 

C=  12.97:  [«]£=   -  65.27°  ;<:=  51.12  :[a]»=  -58.94° 

On  addition  of  water  to  the  alcoholic  nicotine  acetate  solu- 
tion, the  rotation  becomes  right-handed  ;  conversely,  aqueous 

Gennari,  §  46,  p.  160. 

L,andolt.  §  60,  p.  208. 

L,andolt.  §  52,  p.  181. 

Pribram,  Hein,  §  56,  p.  19^. 

Pribram,  §  76,  p.  282. 

Ivandolt,  §  52,  p.  182  ;  Hein,  §  62,  p.  229. 

Hein,  \  62,  p.  229;  Nasini  and  Gennari  :  Zt.schr.  phys.  Chem.,  19,  117  ;  §  46,  p.  163. 

Hein,  §  48. 

Schwebel :  Ber.  d.  chem.  Ges.,  15,  2850. 

Schwebel. 

Nasini  and  Pezzolato  :  Zt.schr.  phys.  Chem  .  12,  501. 


712  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

solutions  of  the  salt  become  left-rotating  on  addition  of  alco- 
hol. The  aqueous  solutions  of  the  sulphate  and  hydrochloride, 
which  are  right-rotating,  behave  in  the  same  manner. 

The  separation  of  nicotine  from  the  alcoholic  solutions  of 
its  salts,  by  means  of  triethyl  amine,  aniline,  and  ammonia, 
may  be  followed  by  the  polariscope  ;  a  method  of  determining 
nicotine  is  based  on  the  complete  displacement  by  solutions  of 
potassium  and  sodium  hydroxides.  The  decompositions  are 
not  absolutely  complete  in  aqueous  solutions.1 

Boric  acid  added  to  an  alcoholic  solution  of  pure  nicotine 
produces  a  slight  decrease  in  the  left  rotation. 

HYDRONICOTINE,  C10H16N,.  Boiling-point,  263°  to  264°. 
<*"  =  0.993. 

Water  ..............   ^  —  i3-7°>     [>]/>  =    -  i5-4<>  2 

</-CoPELLiDiNE,  C8H17N.  Boiling-point,  162°  to  163°. 
d  =  0.838. 

d    :=  0.8381,     IO]D  =  +  36.50°  3 
-        d*  =  0.8375,        "      =  +  36.93* 

/-CoPELLiDiNE.     Boiling-point,  162°  to  164°. 
d    =  0.8386,     [or]/)  =  —    7.91°  3 

rf19  =  0.8347,       "        -  16.26°  4 

dMsocoPELUDiNE,  C8H17N.     Boiling-point,  163°  to  166°. 
d™  =  0.8500,     [a\D  =    -  25.93°  4 

/-ISOCOPELLIDINE.     Boiling-point,  162.2°  to  162.5°. 

d     =0.8445,     [a]D  =    -  25.93°  ;1 
dr'    -  0.8435,  -  57-03  * 

TETRAHYDROQUINALDINE,  C10H1SN.  The  racemic  base  has 
been  split  by  Pope  and  Peachey5  by  the  dextrocamphorsul- 
phonic  acid  method.  They  give  for  the 


l-ffase,  rfM-s  =  1.02365,     [a]£  =   -  58.12 
d-Base,  d™  =  1.0192,       [<*]£  =  +  58.09 

Pezzolato  :  Gazz.  chim.  ital.,  10,  780. 

Etard  :  Compt.  rend.,  97,  1219. 

I<evy,  Wolffenstein  :  Ber.  d.  cherrf.  Ges.,  28,  2271. 

I^cvy,  Wolffenstein  .  Ibid.,  Ges.,  ap,  1960. 

J.Chem.  Soc..  75,  1066. 


GLUCOSIDES  713 

For  the  df-base,  Ladenburg1  found  nearly  the  same  value 
after  tartaric  acid  resolution.  In  their  paper,  Pope  and 
Peachey  give  the  constants  for  salts  and  other  derivatives. 

27.  Glucosides 
SALICIN,  C13H18O7- 

Water  ..........  p  =  i  to  3,       [a]%  =  —  65.17  +  0.63  />  2 

Water  ..........  p  =  4-938>     d™  =  i«oi35,     [<*]/°  =   -  62.56  3 

Water  ..........  p  =  2.78,     \OL\J  =    -  73-4°  * 

Alcohol  (  50  p.  c.  )  ,     [or]  />  —  —  50.30  —  0.05026  q>, 

t  =  22°  tO  26°,  ?  =  90  tO  96  5 

HELICIN,  C13H16O7  +  :!/4H,O. 

Alcohol  (50  p.  c.  )  ......   /  =  20°,  p  =3  to  9,   [<*]/>=    —  47-O3°  6 

WTater  ......  p  =  1.351  (anhydrous),     d™  —  1.0084,     [ar]*°  =    -  60.43°  3 

POPULIN,  C20H22O8- 

Water  ...............  p  =  I,     L<*L'  =    ~  53°  7 

PHLORIDZIN,  C21H30OU  +  2H2O. 
Alcohol    (97  p.  c.  )  ....  />  =  i  to  5,     [or]»-s  =   -  49.40  —  2.41  p  s 

Alcohol  ..............  />  =  4-6,     [a]/>  =    -52°19 

Wood  alcohol  ........  /  =  3.9,  —  52   )* 


AMYGDALIN,  C.,0H27NOU  +  3H..O. 

MD=    -35.5 


010 


APIIN,  C.,-H32O16.     Weak  alcoholic  solution. 


=4-173°" 


CONIFERIN,   C16H22O8  +   2H,O. 
Water  ......  />:=  0.621  (anhydrous),     ^  =  0.9998,     [a]£=  —66.90°  3 

GLUCOVANILLIN,  CUH1SO,  -f-  2H2O. 

Water  ........  /  =  0.896  (anhydrous),  rf»  =r  i.oon,   [a]^=—  88.63 


o  :t 


1  Ber.  d.  chem.  Ges.,  27,  75. 

2  Hesse:  Ann.  Chem.  (Uebig),  i76,  116. 

3  Wegscheider  :  Ber.  d.  chem.  Ges.,  18,  1600. 

4  Biot,  Pasteur  :  Compt.  rend.,  34,  607. 

5  Sorokin  :  J.  prakt.  Chem.,  [2],  37,  320. 

6  Sorokin  :  Ibid.,  [2],  37,  291. 
"  Biot,  Pasteur  :  Loc.  ctt. 

8  Hesse:  Ann.  Chem.  (I^iebig),  176,  117. 

9  Oudemans  :  Ibid.,  166,  69. 

10  Bouchardat  :  Compt.  rend.,  19,  1174. 

11  I,indenborn,  Gerichten  :  Ber.  d.  chem.  Ges.,  9,  1123. 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


CONVALLAMARIN,    C2SH44O12. 

Alcohol [<*]/>  =    -  55e  ' 

DIGITONIN,  C,7H46O14  +  5H..O. 

Acetic  acid  (75  p.  c.)  .-/>       2.8,     [a]/,       —  50°  2 

IVY  LEAF  GLUCOSIDE,  C3aH54On. 

Alcohol t=22°,     [>]/>        _  47.5°  » 

ISOHESPERIDIN,  C22H2gOI2  +  2H2O. 

Alcohol....".' [«]/)-  -89°* 

NARINGIN  (Aurantiin,  Hesperidin ) ,  C21H26On. 

Water c  =  20.46,     /  =  T7°,     [a]z>=  —  84.5°  j5 

Alcohol £  =    7-299,  *  =  17,       [a]z>=:— 87.6    j 

OUBAIN,  C^H^O,,  H-  7H,O- 

Water /  — 0.65,     [a]g  =  -3406 

PICEIN,  C14H18O7  -f  H2O. 

Water p  =  2.5,       [>]z>-    -84°" 

CONVOLVULIN,  C61H1W,O27.     Melting-point,  140°  to  148°. 
Alcohol [<*]z>—  —36.9°  s 

In  addition,  E.  Fischer  has  produced  a  series  of  simple  glu- 
cosides  synthetically  and  has  determined  their  constants  of  ro- 
tation : 


OOIVCI1V. 

V 

"  20' 

L"J/>. 

rv.nst.ner.' 

a-MethyW-glucoside 

Water 

5 

4-  157.6° 

28,   1152 

a-      "      -/- 

5 

156.9 

28,    II52 

a-Ethyl-rf- 

" 

9.002 

1.025 

-f  150.6 

28,   1154 

" 

8.897 

f  150-3 

28,  1154 

a-Methyl    galactoside 

« 

9.119 

1.026 

f  179-0 

28,   1155 

ft.          "                            "            10 

Borax  sol. 

8-5 

+        2.6 

28,   1155 

Ethyl 

Water 

9-47 

1.0273 

4-  178.75 

27,  2481 

Benzyl  arabinoside  •  .  . 

'« 

1.03 

I.OOI3 

-f  215.2 

27,  2482 

Methyl  glucoheptoside 
nr-Methyl  xyloside     .  . 

„ 

10.06 
9-32 

1.0338 
1.026 

-    74-7 
-f  153-2 

28,  1156 
28,  1158 

ft.       " 

<  c 

9.14 

1.024 

65-9 

28,  1157 

Methyl  rhamnoside.  •  . 

" 

9.68 

1.024 

—   62.2 

28,    1159 

"       sorboside   

" 

9.12 

1.028 

-    88.5 

28,  1160 

" 

8.19 

1.026 

—   88.9 

28,  1160 

Mandelnitrile     glu-  \ 
cosiclc                     i 

H 

8.25 

I.OI8 

-    26.9 

28,   1509 

Acetone  rhamnoside  .  . 

U 

9.16 

I.OI7 

+    17-4 

28,  1163 

Diacetone  arabinoside 

" 

2.41 

1.003 

H-     5-4 

28,   1164 

glucoside 

" 

4-93 

I.OOS 

-    18.5 

28,   1167 

fructoside- 

«' 

7-29 

I.OI4 

-  161.3 

28,    1165 

Triacetone  mannitol  .  . 

Alcohol 

9.58 

o.Sir 

4-    12.5 

28,  1168 

Tanret  :  Jahresbericht,  1882,  p.  1130. 
Vernet :  Jahresbericht,  1881,  p.  991. 
Will  :  Her.  d.  chem.  Ges.,  ao,  294. 
Tanret  :  Bull.  soc.  chim.,  [3],  n,  944. 
Her.  d.  chem.  Ges. 


-  Kiliani  :  Her.  d.  chem.  Ges.,  34,  339. 
4  Tanret  :  Bull.  soc.  chim.,  [2],  49,  ai. 
r>  Arnaud  :  Compt.  rend.,  107,  1162. 

*  Kromer  :  Chem.  Centibl.,  (1894),  I,  635. 
10  In  aqueous  solution  inactive. 


BITTER  PRINCIPLES  AND  INDIFFERENT  BODIES 


715 


Also  :  df-and  /-Methylmarmoside. 

Water  .......  />    -  S,     [a]D  =  ±  79.2  to  79.4 

d-lcrm  :  Water  . 


Alcohol 


i,  r  0^.5-  ) 

=  »,       "  79-2 

=!,          "        =4-87.3     ' 


28.  Bitter  Principles  and  Indifferent  Bodies 
Santonin  Group 

The  following  data,  unless  otherwise  stated,  are  from  Carne- 
lutti  and  Nasini.3  According  to  these  authors  the  concentra- 
tion is  without  effect  on  the  rotation  : 


Substance. 


Observer. 


Santonin Alcohol  97 

"        90    15 

11         "        80    15 

"          Chloroform   15 

' "             26 

Metasantonin 26 

Santonide 26.5 

"               "                  20 

lletasantonide 26 

Parasantonide 26 

"               "             20 

Santonic  acid 26.5 

Methyl  ester 26.5 

Ethyl  ester 26.5 

«-Propyl  ester 26.5 

Allyl  ester "             26.5 

z-Butyl  ester 27 

Parasantonic  acid 26 

Methyl  ester 26 

Ethyl  ester 26 

Propyl  ester 26 

Santonyl  chloride 26.5 

Santonyl  bromide 26 

Santonyl  iodide 26 


2 
2 
2 

2-IO 

6 

i-5 
1.5 

3.1-30.5 

i-5 

i-5 

2.6-50 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 

6 


175.4 

176.5 

I7I.5 

I7L37 

292.15 

744.6i 

754 

223.46 

897-25 

891.7 

70.31 

52.33 

45-35 


Hesse.  < 


xasini.-- 


Nasini.  « 


39-54 
41.63 

98-51 

108.91 

99.98 

91.27 

I3-I4 

100.53 
99.21 


1  Fischer,  Beensch  :  Ber.  d.  chem.  Ges.,  29,  2927. 
-  Ekenstein  :  Rec.  trav.  chim.  Pays- Has,  15,  221. 

3  Ber.  d.  chem.  Ges.,  13,  2208. 

4  Ann.  Chem.  (L,iebig),  176,  125. 

5  R.  Accad.  L,incei,  13,  1892. 

6  Loc.  cit. 


7i6 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


Substance. 

Solvent. 
Per  cent. 

t 

c 

[«]/>• 

Observer. 

Alcohol 

ij. 

2 

—  121  6 

ii 

1  i 

O  7 

4-      76  77 

Dehydrophotosantonic   > 
arid                                .    1 

" 

1o 
20 

1.4 

+     31-9 

Villavec- 
chia.i 

<( 

2  8 

1       20  A. 

Isophotosantonic  acid  •  •  • 
Monoacet  ylisophoto-  •» 

« 
<  i 

II 
'7 

2.4 

0.9 

+   124.17 
+     58.6 

v    Canniz- 
l  zaro,  Fa- 
\  bris.s 

'  '      Q7  % 

OC    S 

«             t« 

"     80  % 

22.5 

3 

2    1 

*o-° 
26  t; 

Hesse.^ 

Na  salt 

Water 

-"O 

*    O 

^"•D 

J 

Hyposantoninic  acid  
Dihydrosantinic  acid  

22.5 

J9-3D 
4.62 
•f    62.07 

+       ft  A    11 

I  Gucci 
and 

!  G  r  a  s  si- 

Santoninaminesulphate.  . 
Santoninamine    hydro-  ^ 
chloride  .  . 

.: 

•  • 

.... 

°4-37 
-  103.67 

-  136.83 

f  Cristal- 
di.< 

The  following  data  are  given  by  Nasmi5  for  the  specific  rota- 
tion of  some  bodies  of  the  santonin  group  for  light  of  different 
colors  : 


B 

C 
I) 
E 


1 

£ 

Santonin.                             Meta- 
s.-uitonin. 

Santonide. 

Para- 
santonide. 
Chlorof. 

Santonic 
acid. 
Chlorof. 
c  —  27  192 

Chloroform. 

cmoro- 
Alcohol.       form- 

Alcohol.  Chlorof. 

1 

q  =  75  to  96.5 
/  =  20°. 

sa^p^ 

/"t$* 

c  =  3  to  30 

t=20°. 

/  =  20°. 

/  =  20°. 

686.7 

—  I40.I      +0.2085? 

—110.4'  +  92 

+    442 

•   484 

+    580.5 

-    49 

656.2 

-149.3     +0.1555? 

—  118.8    +  104 

+    504 

+    549 

+    655-6 

-    57 

589-2 

—  202.7     +0.3086? 

-161.0,  +124    +    693 

:-    754   +    891.7 

-    74 

526.9 

—  285.6         ;     0.5820? 

—  222.6     +  167 

+     991 

+  1088 

+  1264 

-  105 

5^8.3 

-302.38+0.6557? 

-237.1      +  182 

+  1053 

+  1148 

+  1334 

—  112 

486.1 

—  365.55   +0.8284?    -261.7       +217 

+  1323 

+  1444 

+  1666 

-137 

438-3 

534.98    r  1.5240? 

—  380.0     4-257 

+  201  1 

+  2201 

+  2510 

-197 

422.6 



238l 

+  26lO 

+  2963 

230 

1  Her.  d.  chem.  Ges.,  18,  2859. 

»  Ibid.,  19,  2^60. 

*  Ann.  Chem.  (L,iebig),  176,  125. 

4  Gazz.  chim.  ital.,  aa,  i. 

<•  R.  Accad.  I^incei,  [3],  13,  1882. 


BITTER  PRINCIPLES  AND  INDIFFERENT  BODIES  Jl 

Andreocci1  gives  : 

^/-Disantonious  acid  .............  [<*]/>  =  "    85.9° 

/-  "  "    ..............         "    =-85.8 

^/-Santonious        "    ..............  =4-74.6 

/-  "  "    ..............         "    =  —  74-3 

Desmotropodisantonious  acid.--.  —64.5 

Desmotroposantonious   acid  ......          '   =  —  53.3 

Other  Vegetable  Substances 

ASEBOTOXIN  (Andromedotoxin),  CUH51O10. 

Water  ..................   c  =  2.8,       [<*]»  =     -    9.7°\2 

Chloroform  .............   c  =  0.41,  =  -f  10.1   j 

PlCROTtoxiN,  C,,H14O5. 

Alcohol  ..............  ^  =  3-125,     [<*]/  =     -  28.1°  3 

ECHICERIN,  CgoH^Oj. 

Ether  ................    c  =  2,  \_a]%  =  +  63.75°    * 

Chloroform  ..........    c  —  2,  =  +  65.75 


ECHITIN,  CS2H5,O,. 

[«]^  =  -f  72-5°l 
=  -f  75-3  ) 


Ether  ................    c  =  2,  -  5 


Chloroform c  =  2, 

ECHITEIN,  C4.,HTOO. 

Ether *  =  2,  [«]g  =  +  88 

Chloroform t  =  2,  "    =  -f  85 


ECHIRETIN,  CsjH^O^,. 

Ether c  =  2,  [a]g  =  +  54-8°  5 

EUPHORBON,   C15H24O. 

Ether *  =  4,  [a]g  =  +  «-7 

Chloroform £T  =  4,  '    =  +  l8-8 

ANTIARONIC  ACID,  C6H10O5  (from  Antiaris  toxicaria). 
Water [«]/>  =  +  3°°  7 

LUPEOL,  CMH42O?. 

Ether <:  =  9-97,       [«]^  =  +  27°  * 

Atti.  R.  Accad.   I*incei,  [5],  4.  164. 

Zaayer  :  Rec.  trav.  chim.  Pays- Has,  5,  313. 

Bouchardat  and  Boudet :  J.  pharm.  chim.,  [3],  33,  288. 

Jobst  and  Hesse  :  Ann.  Chem.  (Liebig),  178,  49- 

Jobst  and  Hesse  :  Loc.  cit. 

Hesse  :  Ann.  Chem.  (Liebig),  193,  195. 
:  Kiliani  :  Arch.  der.  Pharm.,  334,  438. 
«  Likiernik  :  Ztschr.  physiol.  Chem.,  15,  415 


7i8 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODI1 


PHASOL,  C15H,4O. 

Chloroform  . . . 


[a\D  =  +  30.6°  r 
[a]«3  =  +  76.2° 
MS-  +  38.20" 
f>]'/5  =    -29.3°* 

p  =  3.156,      M^  =    -37-5°* 

ClNCHOL,  CaoH34O. 

Chloroform />  ==  6,  [a]^f  =  —  34.6°  5 

29.  Biliary  Substances 
CHOLESTERIN,  C,6H44O(?)  (melting-point,  145°)  and  C26H44O 


OT-LACTACEROL,  C^H^O. 

Chloroform p       2.372, 

/?-L,ACTACEROL,  C^H^O. 

Chloroform p  =  4, 

QUEBRACHOL,  C^H^O. 

Chloroform p  =  4, 

CUPREOL,  C20H34O. 

Chloroform 


Anhydrous  ether 

chloroform 


c  =  2,       ^/>  =    —31.12  > 

£  =  2  5  8 

.  _  > 

«J^5  =  -  37-02,      -  37.8i,     -  38.63°  f 

from   which  .....       [<*]$=    —  36.61  —  0.249  r 

Solutions  of  the  anhydrous  substance  in  ether  (c  =  7.941), 
and  in  petroleum  spirit  (c  =  10)  gave,  in  agreement  with  each 
other,  the  following  numbers  :  7 


tight. 

B. 

C. 

D. 

E. 

fe 

F. 

£. 

[*]  = 

—  20.63 

-25-54 

-31-59 

39.91 

-41.92 

-48.65 

—  62.37 

°  =   ~  l8'8° 


Cholesterin  Ester  of  Oleic  Add,  CMH43O.(CWHMO).     From 
dog  serum.     Melting-point,  41°  to  45°. 

Equal  parts  of          ) 
alcohol  4   chloroform  j  c  "  7'«4' 

Ukiernik  :  Ztschr.  physiol.  Chem.,  15,  430. 

Hesse  :  Ann.  Chem.  (Uebig),  234,  248. 

Hesse  :  Ibid.,  an,  272. 

Hesse:  /bid.,  aa8,  291. 

Hesse  :  Ibid.,  228,  294. 

Hesse  :  /£<</.,  193,  178. 

7  Ifindenmeyer  :  ].  prakt.  Chem.,  [ij,  90,  323. 
•  Hiirthle  :  /tschr.  physiol.  Chem.,  ai,  337. 


BILIARY    SUBSTANCES 


719 


PHYI    STERIN,  C,6H44O.     Melting-point,  132°  to  133°. 
Chloroform p  =  1.636,     [«]^  =  —  34.2°  l 

PARAPHYTOSTERIN,  C^H^O. 

Chloroform c  =  3.45,       [«]z>  =    —  44-l°  ' 

ISOCHOLESTERIX,  C,6H44O.       Melting-point,  138°  to  138.5°. 

Ether c=  7-344,     [<*]/>  =  +  60°  ' 

11       ^  =  6.435,         "       =  +  59.1°* 

PARACHOLESTERIX,  C26HUO.    Melting-point,  134°  to  134.5°. 
Chloroform p  —  2.7,     d  —  1.4717,     [a]»  =   -  28.88°  5 

CAULOSTERIN,  C26H44O.     Melting-point,  158°  to  159°. 

Chloroform c  —  5.0905,   [<*]z>  =  —  49.6°  6 

ERGOSTERIN,  C.^H^O. 

Chloroform c  —  3.33,       [a]/?  =  —  114°  7 

KOPROSTERIX,     C.,5H44O.       From    human    feces.     Melting- 
point,  95°  to  96°. 
Ether f=  13.2  (1.581  gram  subst.  in  12  cc.  ether),  [or]/)  =  4-  24°  8 

GLYCQCHOLIC  ACID,  C,6H43NO6. 

Alcohol c  —  9.504.     Rotation  independent  of  the  concentration. 

Light.  C.  D.  E.  t>*.  F.  G. 

! ^ 

[or]  =  21.6       -  29.0       +  37.9       +  40.0      +  48.7       +  56.8 » 

Sodium  Salt,  NaC,6H4,NO6. 

Alcohol c  =  20.143,     [<*]/?  =  +  25-7°)  9 

Water c  =  24.928,  "   =  +  20.8  } 

The  concentration  is  without  influence. 
TAUROCHOLIC  ACID,  C26H45NSO7. 

Sodium  Salt,  NaC26H44NSO.. 

Alcohol £-.=  9.898,    \_a-]D  =  -f-  24.5°,       [ajyr^  +  390)10 

Water c  =  8.856,         "    =  =  +  21.5  "   =  +  34  ) 

1  Hesse:  Ann.  Chem.  (Liebig),  192,  177. 

-  Ivikiernik  :  Ztschr.  physiol.  Chem.,  15,  430. 
3  Schulze  :  Ber.  d.  chem.  Ges.,  12,  149. 

*  Schulze,  Barbieri  :  J.  prakt.  Chem.  [2],  25,  170. 

•'•  Reinke,  Rodewald  :  Ann.  Chem.  (t,iebig),  207,  229. 
«  Schulze,  Barbieri:  J.  prakt.  Chem.,  [2],  25,  166. 
7  Tanret  :  Ann.  chim.  phys.,  [6],  20,  289. 

s  Bondzynski  and  Humnicki :  Ztschr.  physiol.  Chem.,  22,  396 ;  Bondzynski  :  Ber. 
d.  chem.  Ges.,  29,  476. 

9  Hoppe-Seyler :  J.  prakt.  Chem.,  [ij,  89,  261. 
1(>  Hoppe-Seyler  :  Loc.  cit.,  p.  263. 


720  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

The  concentration  is  without  influence. 

CHOLAUC  ACID,  CMH40O6(+  H,O)  and  (  +  2V,H,O). 

a.  Anhydrous  Cholalic  Add. 

From  ox  gall :  Alcohol,  c  ==  3.338,     [a]/?  =  +  50.2°  ) J 
"     dogfeces:       "       £—2.942,          "    —-[-47.6    j 

b.  Cholalic  Acid  with  21/,  mols.  water  of  crystallization.- 


c. 
Anhydrous. 

M* 

Anhydrous. 

[*]/>. 

Hydra  ted. 

6.070 

+  35.4° 

+  31.9° 

4-433 

+  34.8 

+  31-4 

Solutions 

2.707             +35-2 

+  31.7 

in  alcohol 

2.659 

+  33-9 

+  30.4 

2.030 

+  34-5 

+  3I-I 

1.804 

+  34-2 

+  30.8 

Cholalic  acid  with  2!/8  mols.  water.  Alcohol,  c  =  2.962  (2.659  anhydrous)  : 3 


Une. 

B. 

C. 

D. 

E. 

b*. 

F. 

G. 

M 

For  hydrated  ) 
substance  ) 

+  25.3 

+  27.0 

+  30.4 

+  40.1 

+  42.2 

+  47-3 

-f  60.8 

-f 

w 

For  anhydrous  ) 
substance  I 

+  28.2 

4-30.1 

+  33-9 

+  44-7 

+  47-0 

+  52.7 

-f67.7 

+ 

78.0 


c.   Cholalic  Add  Alcoholate,  C,4H40O5  -f  C2Hr>OH.4 
Solution  in  alcohol  of  97  volume  per  cent. 


p 

l«K 

with    crystal 
alcohol. 

pure  acid. 

pure  acid. 

1.9207 

1.7262 

0.81518 

l6.4 

15 

+  3L30° 

\    34.83° 

16.2 

1-3340 

1.1989 

0.81050 

23.4 

23.4 

+  31.12 

+  34.63 

23 

I.I525 

1.0358 

0.81006       20.4 

20.4 

+   3L30 

+  34.83 

21. 

2.9204 

2.6246 

0.81493        21.  1 

21.  1 

+  3r-72      +35.29 

21.2 

0-9559 

0.8591 

0.81502        14.2 

15 

+  32.02 

+  35.63 

12.2 

0-4794 

0.4309 

O.8l26o 

13.4 

15 

+  31.85 

+  35-44 

14 

1  Hoppc-Seylcr  :  Loc.  cit.,  p.  266. 

1  Hoppe-Scyler  :  IMC.  cit.,  p.  267. 

3  Hoppc-Seyler  :  J.  prakt.  Chem.,  [i],  89,  267. 

«  Vahlen  :  Xtschr.  physiol.  Chem.,  ai,  253. 


BILIARY    SUBSTANCES 


721 


Potassium  Salt,  KC.,4H3,,OV 
a.   Aqueous  solutions. 


c  = 
c  = 
c  = 
c  — 

C  — 

c  = 

6.004,    \_ai\D  =  4-  28.2°  i  J 
7.000,         "  =  -f-  27.5 
12.562,         "  ==  -f  25.9 
16.749,               -4-24.6 
22.332,                  -24.1 
29-775,               =  +  24.9  } 

P.              d  .                         [a]*,. 

1-0433 

3-4940 
« 

5-4570 

i  < 

6.6825 
b.  Alcoholic  solutio 
P 

I.OO2O              15             4~  29.10°       -|  -1 

0-9993          30         +  30.79 
1-00975          5         4-  27.23 

1.00923           20             4-  26.89 

1.01498       ii        4-  27.69 
1.00695       40        4~  27.06 
1.01843       24        -f  26.51 

ns. 

d'2b  =  0.81027,    [a]^  =  4-  31.60°  i3 
d1'  =  0.81875,    [ajg  =  4-  31-27  j 

I.ight.                 C. 

D.                          E.                           b.                          F. 

O]  =  |      +23.7               30.8           +38-5           4-40.9          4-47-5°  * 

I                                          i                     i 

Sodium  Salt,  NaC24H39O5. 

a.  Aqueous  solutions.5 
c  =  19.049. 

Ught.                R.                   C.                  D.                  E.                   b.                    F. 

[a]  =          -  19.7 

21.0         -f  26.0         +33-1         4-34-0         4-42.0° 

Hoppe-Seyler  :  J.  prakt.  Chem.,  [i],  89,  270. 

Vahlen :  Ztschr.  physiol.  Chem.,  21,  253. 

Vahlen. 

Hoppe;Seyler :  Loc.  cit.,  p.  269. 

Hoppe-Seyler  :  Loc.  cit  ,  p.  271. 

46 


722 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


p.      d<. 

<• 

wi. 

7.5888 

1.01969 

22.5° 

+  27.46°  1 

4.9450 

1.01298 

24 

+  28.19 

4.0419 

1.00826 

20 

-f  27.65 

2.2920 

1.00595 

23 

+  30.61 

From  this,   the  specific  rotation   appears  to  be  increased  by 
lowering  the  concentration. 

b.  Alcoholic  solution. 

c  =  2.230,     [a]/?  =  +  31.4°  - 

Cholalic  Add  Methyl  Ester,  CH3.C24H39O5.     Crystals. 
Alcohol c=  4-59,     l»  =  +  31-9° 

Cholalic  Add  Ethyl  Ester,  C2H5.  C24H39O5.     Crystals. 8 
Alcohol c  =  18.479. 


Ivight. 

B. 

D. 

E. 

b. 

[a]  =        +  25.4 

+  32.4 

+  40.5 

-f  42.3° 

CHOLEINIC  ACID,  CJH^O4(?).--C25H42<V 

Alcohol. 


p- 

d'. 

/. 

Mi. 

2.469 

0.8110 

24° 

+  48.87° 

1.786 

0.8105 

22 

+  49-52 

0.862 

0.806  I 

24 

+  48.60 

0.694 

0.8050 

21 

+  52.49 

CHOLANIC  ACID,  C^H^O,  +  V4H2O. 

Barium  Salt,  Ba3C25H35O7  +  '/4H2O(?). 

Water  ........  ^^3.638,     d=  1.017,     [(*]D  =  -f  49-37°  4 


49.86°  ' 


DESOXYCHOLIC  ACID,  C24H40O4. 

Alcohol,  p  =  1.968,     d™'4  as  0.81142, 

>  Vahlen  :  Aor  .  «/. 

*  Hoppe-Seyler  :  Loc.  cit.,  p.  271. 

*  Hoppe-Seyler:  Loc.  cit.,  p.  272. 

«  I^atschinoff  :  Ber.  d.  chem.  Ges.,  19,  475. 


GELATINOUS   SUBSTANCES  723 

LITHOFELLINIC  ACID,  C20H36O4.     Melting-point,  205°. 

Alcohol [or]/,  —  -f  13.76°  l 

30.  Gelatinous  Substances 
a'-GLUTiN  (ordinary  gltitin,  gelatine). 

Water,,  =  6.ia|'  =  24t025°'       W»  =    ~  ^^ 

(t  =  35  to  40,  '   =  —  123.0 

Water,  ,^  3-06  S^24t°25'  ~  ^5 

f/  =  35,  '   =-125-0 

The  rotation  decreases,  therefore,  with  the  temperature  ;but, 
on  the  other  hand,  it  does  not  appear  to  be  much  influenced 
by  the  concentration. 

The  effect  of  acids  and  alkalies  is  shown  by  the  following 
experiments  : 

Glutin  solution  with  c  =  3.06 : 

Mixed  with  equal  vol.   of  ammonia [a]/>  =  —  130.5°  i  * 

"         "     a  few  drops  of  sodium   hydroxide "    =  —  130.5    | 

"         "     the  same  volume  of  hydroxide "    = — 112.5    ( 

"         "      "       "  "        "  acetic   acid "    =     -114.0    j 

The  specific  rotation  of  aqueous  glutin  solutions  is  decreased 
by  long  boiling.3 

/?-GivUTiN.  Obtained  by  heating  i  part  of  gelatine  with  2 
to  3  parts  of  water,  in  a  pressure  bottle,  for  several  days  to 
100°,  until  the  liquid  no  longer  solidifies  on  cooling.4 

On  account  of  lack  of  uniformity,  the  products  showed  dif- 
ferences in  the  rotating  power  : 

Product  with  1.40  p.  c.  ash.     Water,  c  =  5,      [«]^5'5  =    —  130.6° 
"     1.96    "       "  "     <r  =  5.      M#    =-125.8 

Multirotation  was  not  detected. 

The  following  observations  were  made  on  variations  in  the 
rotation. 

i.  The  rotation  of  aqueous  solutions  decreases  with  in- 
creasing dilution  : 

f=          5  43  2  r 

[a]£=    -120.7     •-  118.1      -II7-5      -114-0    —113.7° 
1  Roster:  Gazz.   chim.  ital.,   9,364;  Hoppe-Seyler    and  Thierfelder :  "  Handb.  d. 
phys.  u.  path.-chem.  Analyse,"  6  Aufl.,  p.  209. 

-  de  Bar>-  :  Hoppe-Seyler's med.-chem.  Untersuch.,  i,  71. 

9  Nasse  :  Maly's  Jahresbericht,  1889,  p.  29. 

4  Framm  :  Arch,  fur  die  ges.  Physiol.,  68,  144  (1897). 


724  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

2.  The  addition  of  methyl  and  ethyl  alcohols  in  amount  too 
small  to  produce  precipitation,  decreases  the  rotation. 

3.  Alkali  chlorides  (and  also  KI),  and  also  alkali  nitrates, 
bring  about  a  decrease  in  the  rotation  which  is  independent  of 
time  and  temperature,  but  a  chemical  change  in  the  glutin  is 
not  produced.     Alkali  sulphates  have  no  similar  action. 

4.  Acids  diminish  the  rotation,    and  in  greater  degree  the 
larger  the  amount  used  and  the  higher  the   temperature.     The 
intensity  of  the    action    follows  in   the   order  :  HC1,    H.2SO4> 
HC.HgO.,,  H3PO4.     The  change  does  not  increase  with  time. 
On  neutralization  of  the  acid  the  original  value  of  the  rotation 
is  not  restored. 

5.  Alkalies  and  ammonia  (the  last  in  concentrated  condition 
only)  diminish  the  rotation.     The  decrease  becomes  greater 
with  time,  and  is  not  altered  by  neutralization  of  the  alkali  ; 
a  chemical  change  in  the  glutin  is,  therefore,  produced.1 

CHONDRIN.     c  •=  0.957. 

Water  with  a  few  drops  of  sodium  hydroxide  solution  [<*]/  —   —  213.5°  1  2 
The  liquid  mixed  with  an  equal  volume  of  sodium 

hydroxide  solution "    —  —  552.0 

The  latter  mixed  with  the  same  volume  of  water "    =  —  281.0 

31.  Protein  Bodies 
SERUM  ALBUMIN. 

1.  Neutral  aqueous  solution [#1^  —  —  5^° 

Aqueous  solution,  saturated  with  NaCl "  =      -  64 

acetic  acid  added "  =  —  71 

"        hydrochloric  acid  added  until  pre- 
cipitate formed  redissolves "=    —78.7 

2.  [O]D  =    -  62.6  to  -  64.6°  * 

3.  Serum  albumin  crystals  : 

Third  crystallization p  .._  2.07       \ct\D        —  62.6°  )  » 

Still  further  purified />  =  2.345          "    =  —  60. 1    ) 

4.  Serum  albumin  crystals  : 

Water p  =  3.92,     [a]/,         -61.2° 

"      P       3-2  -61 

Third  crystallization  :          "  =     —  64 
1  Framm  :  Loc.  cit. 

-  de  Bary  :  Hoppe-Seyler's  med.-chem.  Untersnch.,  i,  71. 
»  Hoppe-Seyler :  Ztschr.  fur  Chem.  u.  Pharm.  v.  Erlenmeyer,  1864,  p.  737. 
4  Starke  :  Jahresbericht  fiir  Thierchemie,  1881,  p.  18. 
4  Sebalien  :  Ztschr.  physiol.  Chem.,  9,  439. 
«  Michel :  Verh.  d.  physik.-med.  Ges.  zu  Wiirzburg,  29,  No.  3. 


PROTEIN    BODIES 


725 


LACTALBUMIN. 


Water,  />  2  20, 

"     p  3-32, 

/»  4.23, 

"     p  -3.12, 


[«]/>     -36.6' 
-36.4 

"    =  —  37-0    [ 
"          -38.0    J 


Another  preparation  : 

EGG  ALBUMIN. 
i .   Aqueous  solution  : 
Independent  of  the   concentration [<*]/>  =    —  35-5 


By  addition  of  hydrochloric  acid  . 
2.   Dilute  hydrochloric  acid  : 


35-50)2 
37-7  J 


["]*=    -37-803 

3.  White  of  egg,  fractionated  by  its  solubility  in  ammonium 
sulphate  solutions,  gave 

Fraction  i  soluble  in  concentrated  salt  solution,  3.75 

per  cent   albumin  ............................    [a]/,  =  —  42.90° 

Fraction  2  soluble  in  half-saturated  salt  solution,  8.59 

per  cent,  albumin  ............................         "  —  34-30 

Fraction  3  soluble  in  dilute  salt  solution,  6.48  per 

cent,  albumin  ................................         "          —  25.  13 

4.  Ash-free  egg  albumin,  wheat  albumin  and  pea  albumin 
made   by    the    process   of   Harnack.'     The   specific  rotations 
refer  to  \a\  D.  6 


Ash-free 
albumin  from 

In  ico  cc. 
solution. 
Gram. 

In  acid  solution. 

In  alkaline  solution. 

The  acid  solution  treated 
with  XaOH 

Not 
dialyzed. 

Dialvzed 
to  turbidi- 
ty and  then 
cleared 
with  HC1. 

until   it 
became 
clear. 

-69.90 
-66.8 

to  alkaline     and  fur- 
reaction      ther  addi- 
\vith        tion  of  sec. 
phenol-     cone.  NaCl 
phthalein.     solution. 

Piep. 

f  A 
Eggs      '   B 
1    '• 

\A 
Wheat  \    B 

(    •• 

0.1365 
0.326 
0.265 

-57-0° 

-54-6° 
-46.2 

"77-5° 
-52.5 

-97-6° 
-  55-9 

0.287                   

0.188         —  93.0 

0.102                     

-88.7 
-72.6 

—  99-3 

—  54-6 

-31.0 

60.2 

Peas-  • 

0.534 

8?  7 

.... 

—  62.0 

°o-/ 

1  Sebalien  :  Ztschr.  physiol.  Chem.,  9,  457,  459- 

-  Hoppe-Seyler :  Ztschr.  fur  Chem.  u.  Pharm.,  18^4,  p.  737. 

3  Starke:  Jahresber.  f.  Thierchemie,  1881.  p.  18. 

4  Bondzynski  and  Zoja  .  Ztschr.  physiol.  Chem.,  19,  n. 
•''  Ber.  d.  chem.  Ges.,  22,  3046  ;  23,  3745  :  25,  204. 

''  Billow  :  Pfluger's  Arch.  f.  d.  ges.  Physiol.,  58,  219. 


726 


CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 


ALBUMOSES  (  Propeptones ) . 1 
Protoalbumose : 


! 

Dissolved  in  hydrochloric  acid 
of  o  04  to  0.08  per  cent. 

Dissolved  in  sodium  carbonate  solution 
of  o.i  2  per  cent. 

A 

c*  =  1.588    [<*]/>  =    -  72.6° 

(*  =  2.198 

/  =  2o°    [a]/, 

-81.2° 

B 

"   =2.277          "             -  79.1 

"   =  2.223 

t  =  21              " 

—  70.6 

C 

"   =  1.925                         -  77.9 

"   =  1.87.3 

i  =  23-5       " 

-80.1 

11 



11  =  2.361 

/=22.5         " 

-79-2 

D 

«   =  1.366          "             -  73.2 



.... 

.... 

E 

"  =  I.68I                         -  71.4 

"   =  1.904 

'=24.5          " 

-76.3 

....                                 .... 

11  =  2.494 

^=24.5       " 

=  —  75-3 

Deuteroalbumose  : 

Hydrochloric  acid 

with  0.06  p.  c.  HC1                          c*  =  i .680  (>]z)  =  -  74.4° 

"    0.04     "  "                             "  =  1.517  "  =  --79.1 

Sodasol.   "     0.12     "  Na^Oa.    Prep.  A  "  =  2.537  "  =  -74.3(77.6) 

"      "     "    0.12     "  "       B  "=1.765  "  =  —75.3 

Salt     "     "     0.5       "  NaCl            "       A  "  =  1.287  "  =  -77-7(77.o) 

"      "     "     0.5      "  "      B   "  =  1.916  "  -  —72.0 

Heteroalbumose  : 

Hydrochloric  acid  of  0.07  p.  c.  HC1 c=  1.748     [or]/>=  —  68.65° 

Soda  solution c  --.--  1.584         "   =     —60.6 

FlBRINOGEN. 

i.  Dissolved  in  2  to  3  per  cent.  NaCl  solution: 

NaCl  +  ash. 
fc  =  0.426      i. 362  p.  c.       [»  =    -  35-2°  \* 

From  ox  blood U  =  o.4i4  1-752  -36.2! 

1*  =  0.318      1.415  -36.5    I 

[^  =  0.263      1.819     "  -37-7    i 

Mean  "    =     -   36.8    | 

From  horse  blood <:=  0.808      3.744  p.  c.  "         —50.5    J 

Solutions  with  more  than  0.5  per  cent,  of  fibrinogen  can  not 
be  polarized  on  account  of  the  marked  opalescence. 

*c  ash-free. 

1  Kiihne  and  Chittenden  :  Z.  f.  Biologie  von  Kiihne  u.  Voit.,  ao,  (n.  F.  2).  25  1048. 
*  Cramer :  Ztschr.  physiol.  Chem.,  23,  83. 


PROTEIN    BODIES  727 

2.  Dissolved  in  NaCl  solution  : 

XaCl  -•    ash. 
(-£---0.205      i. 045  p.  c.       [«]/>•      —  50.6°  ]  » 

From  horse  blood -j 

i  £  =  0.532      2.251  =-53-9 

L£  =  0.291      2.409     "  —54-1 

Mean          '•   =  —  52.5 

3.  Dissolved  in  o.  i  per  cent,   solution   of  sodium  carbonate  : 

Na2C03  +  ash. 

C  2=  0.481   1.788  p.  C.   [a]z>  =  —  46.7°  i  * 

£  =  0.225   1.341  "  -44-5 

£  =  0.400   1.611  "  —45-7 

£  =  0.592   2.284  "      "  —45-1 

SERUMGLOBULIN. 

Salt  solution WD  =    —  47.8°  3 

CRYSTALLIN. 

From  the  crystalline  lens  : 

or-Crystallin  :  Water,  p  =  3.29,  [<*]/>  '-=  —  46.9°  ^i  4 
/3-Crystallin  :         "       p  =  3.12  "    :      —43-3 

"       p=i.Bo          "  -43-1 

Albumoid  from  the  crystalline  lens  : 

Water ^  =  2.33,     [a]D  =    -  5°-9°)  5 

"       P=2.$l,  "     =  —  52.2    j 

VlTELLIN. 

"   =     -43-35 

SYNTONIN. 

From   the  myosin    of  muscles  by    solution    in  very   dilute 
hydrochloric  acid,  or  by  action  of  strong  hydrochloric  acid  on 
albumin.     Solution  in  very  dilute  hydrochloric  acid : 
[or]z>  =  —  72°  (Independent  of  the  concentration.) 

Almost  the  same  rotation  is  found  in  weak   alkaline  solution. 

1  Mittelbach  :  Ztschr.  physiol.  Chem.,  19,  289. 

*  Cramer:  Ibid.,  23,  86. 

3  FrexJericq :  Arch,  de  Biolog.,  i,  17. 

*  Morner  :  Ztschr.  physiol.  Chem.,  18,  91,  99. 

5  Morner  :  Ibid  .,  18,  77,  88. 

6  Chittenden  and  Mendel :  Jahresher.  f.  Thierchemie  von  Maly,  1895,  pp.  29.  33. 


728  CONSTANTS  OF  ROTATION  OF  ACTIVE  BODIES 

On  heating  the  hydrochloric  acid  solution  in  a  closed  vessel  to 
about  100°,  the  rotation  is  increased  to  : 

Wi>  =   -  84.8°  i 

ALBUMINATES. 

Formed  by  the  action  of  strong  potassium  hydroxide  solution 
on  albumins.     As  maxima  there  were  found  : 

Albuminate  from  serum  albumin [&]D ~  —  86°   1  - 

"     uncoagulated  egg  albumin "       —  47 

"     coagulated         "  "       "=  —  58.5! 

"     casein    (solution    in    strong    KOH. 
Rotation  variable  with  amount  of  alkali) "  =  —  91 

CASEIN. 

In  magnesium  sulphate  solution [<*]/>       —  80°     1  :l 

In  water  containing  4  cc.  of  fuming  hydrochloric  acid, 

per  liter * "  =    -  87        |- 

In  the  smallest  possible  amount  of  sodium  hydroxide 

solution "  =  —  76 

In  aqueous  solution,  as  strong  as  possible [<*]>  =  —  1*7-7°  * 

HEMIELASTIN. 

Water p  —  2.509,     [a]D  =  -  92.7°  (approx. )  5 

Elastinpeptone  : 

Water p  ^  6.14,       [a]/,  =  -  87.9°  6 

I  Hoppe-Seyler :  Ztsch.  f.  Chem.  u.  Pharm.  von  Erlenmeyer  1864,  p.  742. 
-'  Hoppe  Seyler :  Ibid.,  1864,  p.  757. 

*  Hoppe-Seyler  :  Loc.  <-/'/. 

4  Bechamp  :  Bull.  soc.  chim.,  [3],  n,  152. 

5  Horbac/ewski :  Ztschr.  physiol.  Chem.,  6,  337,  343.. 

II  Horbaczewski  :  Loc.  cit. 


GENERAL  INDEX 


Absolute  rotation  for  quartz 413 

Accuracy  of  Laurent  polarizer ...    348 

Action  of  molybdates  and  tungstates  on  malic  acid 250 

tartaric  acid 

Active  bodies,  definition  of i 

formed  in  vegetable  cell 137 

crystals 13 

isomers 130 

from  active  materials 132 

transformation  of 238 

modifications 2 

Addition  of  inactive  bodies 243 

Alkaloids,  determination  of 49^ 

used  in  resolution 103 

Allowance  for  earth's  magnetism 364 

Analysis  of  celluloid 497 

chocolates 487 

cinchona  alkaloids 49s" 

confectionery 4^7 

grape  sugar 491 

milk  sugar 4^8 

sugars 463 

tobacco 503 

Analyzer 311 

Andrews,  observations  of 3S4 

Anomalous  rotation  dispersion 157 

Antimonyl  tartrates 22^> 

Antipodes,  electrical  conductivity 68 

physical  differences 

physiological  differences 72 

refraction 63 

taste 76 

toxicity ?6 

transformation  of *3S 

Apparatus  and  methods 3°6 

for  exact  measurements 361 

Applications  of  optical  rotation 463 

Arons-L,ummer  lamp 433 

Arsenyl  tartrate 226 

Artificial  preparation  of  active  compounds 13° 

Aspergillus  glaucus I23 

Asymmetric  atoms,  definition 44 

carbon '       47 

nitrogen 38  and    52 

sulphur 38  and    53 

Asymmetry,  Pasteur's  theory 44 

Beet  juice  saccharimeter 389 

Behavior  of  antipodes 

a- Benzyl-phenyl-allyl-methyl  ammonium  iodide,  resolution  of 115 

Biot's  determination  of  specific  rotation  .  .  ....    170 

formulas J46 

proof  of 176 

2 


730  GENERAL  INDEX 

Birotation 257 

Bodies  resolved  by  fungi 127 

Boltzmann's  formulas 147 

Bon-bons,  sugar  in 487 

Boric  acid  and  tartrates 246 

Boryl  tartrates 225 

Brix  table  for  sugar  solutions 474 

Broch's  method  for  rotation  dispersion 419 

Bromcamphorsulphonic  acid  in  resolution 113 

Calculation  of  optical  modifications 55  to  65 

sensitiveness 340 

Camphor,  determination  of 497 

oxime,  resolution  of 114 

specific  rotation 191 

Candy,  sugar  in 487 

Cane  sugar  and  alkalies 251 

determination  of 463 

specific  rotation 166 

and  temperature  effect 383 

Caramels 487 

Causes  of  multirotation 273 

Celluloid,  camphor  in 497 

Change  in  specific  rotation  by  dilution 203 

Changes  in  specific  rotation,  various 215 

Chlorcamphorsulphonic  acid  in  resolution 113 

Cinchona  alkaloids '. 498 

Cinnabar,  crystal  rotation 13 

Circular  polarization,  theory  of 41 

Classification  of  active  bodies 7 

Clerget's  formula 484 

Cocaine,  determination  of 501 

specific  rotation 168 

Complex  polymerized  molecules • 23^ 

Compounds  with  several  asymmetric  carbon  atoms 296 

Concentration  and  specific  rotation 203 

of  solutions 458 

effect  on  rotation 169 

Conditions  of  racemization 96 

Confectionery,  analysis  of 487 

Constants  of  rotation 505 

Construction  of  I^ippich's  polarizer 358 

polariscopes 316 

polarization  tubes 436 

Copellidine,  resolution  of 112 

Cornu's  polarizer 344 

Crum-Brown's  hypothesis  on  rotation 299 

Crystalline  form  and  rotation 7 

mixtures 1 1 

Crystals,  rotation  dispersion  of 148 

Crystal  sugar  and  raffinose 482 

Cultures  for  resolution 117 

Density  of  racemic  compounds ' 79 

Dependence  of  rotary  power  on  masses  of  radicals 299 

Determination  of  alkaloids 498 

camphor 497 

cane  sugar 463 

cocaine 501 

concentration 458 


GENERAL  INDEX  731 

Determination  of  galactose 496 

glucose 491 

maltose 495 

milk  sugar 488 

nicotine 503 

percentage  strength 444 

rotation  dispersion 419 

specific  gravity 449 

specific  rotation 165 

Dextrorotation i 

Dextrose  and  calcium  chloride 253 

determination  of 491 

in  diabetic  urine 493 

Diabetic  urine,  sugar  in 493 

Dilute  solutions,  specific  rotation  of 196 

Directions  for  making  polarizations 467 

Dispersion  formulas  of  Boltzmann  and  Trommel 147 

Dissociation  of  active  salts 225 

Double  field  instruments * 351 

wedge  compensation 368 

Earth's  magnetism,  effect  of 364 

Effects  of  errors  of  observation 461 

linkage 293 

temperature  in  saccharimetry 383 

on  specific  rotation 441 

Electric  light 394 

Electrolytic  dissociation 215 

Errors  of  observation,  effect  of 461 

saccharimeters 380 

Esterification,  resolution  by 115 

Esters  of  lactic  acid 284 

malic  acid 283 

Ethyl  dextrotartrate.  specific  rotation     185 

Ethyl  piperidine,  resolution  of 112 

Filtration  of  solutions,  change  of  strength  by 448 

Formation  of  active  bodies  in  vegetable  cell 137 

active  isomers 130 

racemic  bodies 90 

Formula  of  Clerget 484 

Formulas  for  rotation 3  to      6 

of  reduction 175 

French  saccharimeter  scale 372 

Fresnel's  theory 41 

Fric's  saccharimeter 392 

Fungi,  resolution  by 117 

Galactose,  determination  of 496 

Gas  lamps 393 

General  formulas 3  to      6 

Glan's  prism ...  310 

Glucose,  determination  of 491 

Grape  sugar,  determination  of 491 

Gumlich,  rotation  of  quartz 152  and  415 

Guye's  hypothesis 299 

Half-shadow  instruments 335 

by  Cornu 344 

Fric 392 

Heele 34» 

Jellett 342 


732  GENERAL  INDEX 

Half-shadow  instruments  by  Landolt 358 

Laurent 344 

Lippich 351  and  354 

Lunimer 356  and  365 

saccharimeters 387 

Hartnack  prism 310 

Heele's  half-shadow  polarizer 348 

Hemihedry 46 

Kinks'  petroleum  lamp 394 

Historical  remarks 6 

Homologous  series,  rotation  in 290 

Hydrolysis 236 

Hydrolytic  dissociation 223 

Iceland  spar  prism 308 

Illuminating  lamps 393 

Incandescent  light 394 

Influence  of  boric  acid 246 

source  of  light 338 

Inorganic  salts  and  tartrates  ....'. ' 244 

Intense  sodium  light 398 

Isocopellidine,  resolution  of 112 

Isomers.  formation  of 130 

rotation  of 285 

Jellett's  polariscope 342 

lactic  acid  esters 284 

specific  rotation 281 

Lactones.  multirotation  of 275 

Lamps 393 

electric 394 

Kinks'    .   . 394 

Landolt's 397 

mercury 433 

Pribram's 396 

sodium 395 

Welsbach 394 

Landolt's  apparatus 358 

lamp , 397 

large  polariscope 361 

method  for  rotation  dispersion 429 

v.  I  .a  n  ii  rotation  dispersion 423 

of  quartz 415 

Laurel  camphor 15 

Ivaurent's  polarizer 344 

Laws  of  polarization 146 

LeBel  theory 47 

Length  of  tube,  measurement 443 

Levorotation i 

Light,  purification  of 399  and  405 

spectral  purification 405 

Lindner,  data  on  fungi  for  resolution 117 

Linkage  of  carbon  atoms 293 

Lippich's  light  filters 399 

method  for  rotation  dispersion 425 

polarizer 351 

Liquid  racemic  compounds 86 

Lomniel's  method  for  rotation  dispersion 427 

Lumim-r  s  instruments 356  and  365 

Magnetism,  earth's,  effect  on  rotation 364 


GENERAL  INDEX  733 

Malic  acid,  esters 283 

rotation  dispersion 159 

Maltose,  determination  of 495 

Matico  camphor 14 

Measurement  of  angle  of  rotation 306 

length  of  tube 443 

Measuring  flasks 459 

Melting-point  of  compounds 83 

Mercury  lamp 433 

Milk  sugar,  determination  of 488 

specific  rotation 167 

Mitscherlich  apparatus 313  and  326 

Mixture  of  two  active  liquids 240 

Modifications  of  inactive  configuration 140 

Mohr  cubic  centimeters 373 

Molecular  aggregation 227 

asymmetry 44 

rotation 6  and    39 

weight  of  racemic  compounds 77 

Molybdates,  effect  on  rotation 248 

Multirotation 257 

Nature  of  rotating  power 39 

Nicol's  prism 309 

Nicotine,  determination  of 503 

rotation  dispersion 161 

specific  rotation 168  and  181 

Nitrogen  compounds,  asymmetric 38 

Normal  sugar  solution 373 

Number  of  optical  modifications 55  to    65 

Numerical  values  for  specific  rotation 165 

Observations,  errors  in 461 

with  homogeneous  light 327 

Optical  center  and  brightness 407 

of  gravity 399 

constitution  of  active  liquids 43 

modifications 54 

superposition 296 

rotation,  applications 463 

Oxy-acids,  multirotation  of 275 

Parasantonide,  specific  rotation 167 

Pasteur's  theory  of  asymmetry 44 

Patchouli  camphor • 15 

Path  of  rays  in  polariscope 319 

Penicillium  glaucum  in  resolution .121 

Percentage  strength  of  solutions ....  444 

Peters'  saccharimeter 391 

Petroleum  lamp 394 

Phenyl  ethyl  amine,  resolution  of 113 

Physical  and  chemical  behavior  of  optical  modifications 67 

laws  of  polarization 146 

Physiological  differences  in  antipodes 71 

Pipecoline,  resolution  of m 

Polariscopes,  construction  of 3J6 

Polarizer 3" 

Polarization  by  reflection 307 

refraction 3°8 

in  quartz 41 

tubes 436 


734  GENERAL  INDEX 

Polymerized  molecules , ;  .  233 

Pope  and  Peachey,  asymmetric  nitrogen  and  sulphur 53 

Position  isomerism 286 

Powdered  crystal?,  rotation  of n 

Practical  applications  of  rotation 463 

directions 314 

Preparation  of  sugar  scale 369 

Pribram's  lamp 396 

Prisms 308 

Production  of  racemic  bodies 97 

Proof  of  Biot's  formulas 176 

Propylene  diamine,  resolution  of 112 

Propyl  piperidine,  resolution  of 112 

Pure  cultures  for  resolution 117 

Purification  of  light 399 

Pycnometer 451 

Quadruple  field  instrument 356 

Quartz,  rotation  dispersion  of 149 

specific  rotation 151 

Quotient  for  sirups 476 

Racemic  bodies,  production  by  heat 93 

compounds,  distinction  from  active  forms 76 

Racemically  and  structurally  inactive  isomers 144 

Racemization  by  heat 94 

Raffinose 482 

Rate  of  change  in  rotation 266 

Ray  filters 429 

Rays,  path  of,  in  polariscope 319 

Reciprocal  transformation  of  isomers 140 

Reduction  formulas 175 

Relation  of  angles  Q(D  and  a  j 4!5 

Resolution  by  active  compounds 102 

alkaloids ' 103 

crystallization 99 

esterification  and  saponification 115 

fungi 117 

stronger  organic  acids 113 

tartaric  acid no 

of  racemic  compounds 99 

Reusch's  mica  plates 42 

Reversal  of  direction  of  rotation 201 

Rhamnose,  specific  rotation 167 

Ring  structure  molecules 66 

Robiquet's  polariscope 328 

Rochelle  salt,  rotation  of 243 

Rotating  power 2 

Rotation  and  chemical  constitution 282 

crystalline  form 7 

length  of  column 146 

wave  length  of  light 146 

change  in 266 

dispersion 146  and  419 

Broch's  method 419 

l..-in<lolfs  method 429 

v.  I^ang's  method 423 

Lippich's  method 425 

I/nniii'-]  s  method 427 

Seyffart's  method 427 


GENERAL  INDEX  735 

Rotation  despersion,  Wiedemann's  method 421 

in  crystals 148 

in  liquids 154 

of  isomers 285 

powders n 

sodium  light  by  quartz 413 

Rubidium  tartrate 16 

Saccharimeters 366 

Saccharimeter  of  Fric 392 

Peters 391 

Schmidt  and  Haensch 388 

Soleil-Ventzke 385 

Stammer  for  beet  juice 389 

sugar  scale  for 371 

wedge  compensation 366 

Saccharimetry 463 

and  temperature 383 

Saccharose,  determination  of 463 

in  presence  of  raffinose 482 

Santonide,  specific  rotation 168 

Saponification.  resolution  by 115 

Savart's  polariscope 331 

Schmidt  and  Haensch  control  tube 441 

double  wedge  compensation 368 

half-shadow  saccharimeter 388 

simple  wedge  compensation 366 

Schonrock,  rotation  of  quartz 415 

Seyffart's  method  for  rotation  dispersion 427 

.Signs  of  rotation i 

Simple  wedge  compensation 366 

Sodium  chlorate,  rotation  dispersion 153 

flame  lamp 395 

light,  center  of  gravity 402 

Soleil  double  plate 329 

Soleil-Ventzke  saccharimeter 385 

Solubility  of  active  and  racemic  modifications 81 

antipodes 68 

Solutions,  determination  of  percentage  strength 444 

Solvent,  effect  on  specific  rotation 206 

Soret  and  Guye,  rotation  of  quartz 415 

Specific  gravity  and  temperature 456 

determination 449 

rotation 2  and  165 

and  electrolytic  dissociation 215 

effect  of  solvent 206 

temperature 441 

minimum  value  for 197 

of  active  solids 190 

complex  systems 237 

dilute  solutions 196 

Spectral  purification  of  light t 405 

Spontaneous  resolution 99 

Stammer's  beet  juice  saccharimeter 389 

Stereoisomers,  rotation  of 289 

.Strontium  dithionate n 

Strychnine  sulphate 17 

Sugar  in  cakes,  determination 488 

caramels 487 


736  GENERAL  INDEX 

Sugar  in  chocolates 487 

other  products 484 

scale 369  and  371 

sirups,  analysis  of 473 

Sugars,  multi rotation  of , 257 

showing  multirotation 259 

Sulphur  compounds,  asymmetric 38 

Summation  of  rotating  power 296 

Synthetic  conine,  resolution  of 112 

Tables,  calculation  of  cane  sugar 479  and  485 

invert  sugar 481 

correction  for  Brix  readings 474 

expansion  of  water 455 

optical  centers  of  gravity 404 

solutions  for  ray  niters 432 

Tartaric  acid  in  resolution no 

rotation  dispersion 157 

specific  rotation 243 

Temperature  and  saccharimetry,  effect ;>>s 

effect  on  specific  rotation 207 

of  transition 90 

Testing  the  saccharimeter  scale 376 

Tetrahydronaphthylenediamine,  resolution  of 113 

Tetrahydropapaverine,  resolution  of 114 

Tetrahydroquinaldine,  resolution  of 113 

The  100  point  on  saccharimeters 374 

Theory  of  Soleil  double  plate 329 

Tobacco,  nicotine  in 503 

Transformation  of  active  isomers 138 

Transition  temperature 90 

Triple  field  instrument 354 

True  specific  rotation 170 

Tubes  for  polarization 436 

Tungstates,  effect  on  rotation  of  tartaric  acid 248 

malic  acid 250 

Turpentine,  specific  rotation  of 177 

Van't  Hoff,  calculation  of  active  modifications 55 

Van't  Hoff-IveBel  theory 47 

Variable  specific  rotation 169 

Variations  in  specific  rotation 194 

Vegetable  cell,  formation  of  active  bodies  in 137 

Ventzke  sugar  scale 372 

Water  jacket  tubes 438 

specific  gravity  tables 455 

Wave  length  of  light  and  rotation 146 

Wedge  compensation 366 

Weighing  solutions 446 

Welsbach  lamp 394 

White  light  lamps ^ 393 

optical  center " 416 

Wild's  polaristrobometer    .  .  •. 331 

Zirconium  light 394 


INDEX  OF  ACTIVE  SUBSTANCES 


Abietinic  acid 666 

Acetyl  cinchonine 682 

coiiine 709 

quinine 677 

Achrodextrine 608 

Aconine 668 

hydrochloride 668 

Aconitine 667 

hydrochloride 667 

Adonitol 511 

structure 61 

Albumin 72^ 

Albuminates 728 

Albumoid  from  crystalline  lens 727 

Albumoses 726 

Alcohol,  /-amyl «o6 

Aldehyde  sugars 574 

Aldoses 574 

Aliphatic  terpenes 612 

Alkaloids. 667 

aconite  species 667 

cinchona  . 671 

coca  leaves 698 

opium 701 

strychnos  varieties 706 

Alkyl  oxypropionic  acids 518 

Allocinnamic  acid  dibromide,  resolution     109 

Allomucic  acid,  structure 63 

Aminoterebenthene  hydrochloride   .   .   .    640 

/-Ammonium  antimonyl  malate 533 

d-  hydromalate .      535 

/-  hydromalate 531 

d-  hydrotartrate 548 

/-  malate 531 

d-  tartrate 551 

/-  tartrate 563 

Amygdalin 713 

Amyl  acetate 506,  508,  509 

Amyl  acetate,  sec 508 

d-Amylacetic  acid 515 

/-Amyl  alcohol 506,  509 

derivatives 506 

amine 509 

hydrochloride 509 

amylacetate 297,  507,  509 

r-amylmalonate 509 

(/-amylmalonate 509 

benzoate 508 

bromide 506,  509 

brom-w-butyrate 506 

brom-isobutyrate 506 

butyrates 506,  508 

47      . 


/-Amyl  chloracetates 

chloride 

cinnamate 

crotonate 

diamylacetate 

esters,  effect  of  linkage.  . 
Guye'9  hypothesis, 

rotation 

ethers  

formate 

hydrocinnamate 

iodide 

isobutyrate 

lactates  

malonic  acid 

mandelates 

inethacrylate 

a-  and  /3-naphthoates  .  .   . 

oxybutyrates 

palmitate 

phenylacetate 

phenylcarbaminate.  .  .  . 
phenylchloracetate  .  .  . 
phenylpropiolate  ..... 
phenylpropionate  .... 

piperidine 

propionates 

tartrate     

tolylcarbaminates,  o-  ,  ;«-, 

valerate  

Amylodextrine 

rf-a-Amyrilene 

derivatives  .... 

/-a-Amyrilene 

/3-Amyrilene 

derivatives 

a-Amyrin 

acetate     

Audropogon  oil 

Angelica  oil 

Anhydroecgonine. 

hydrochloride 

Anise  oil .( 

Antiaronic  acid  .  .   .   .' 

Antimonyl  tartrate,  dissociation 

Apiin 

Apocinchonidine 

acetyl  derivative 
chlor  derivatives 
chloracetyl  deriv 

Apocinchonine 

chlorate   . 


506,509 
.  506 
.  508 

.   .    508 

•  507 

•  293 
302 
290 

•  509 
508 
508 

506,509 
506,508 

297,  50? 

•  •  507 
298,507 
.  -  508 

.  508 
297 

•  508 
.  -  508 
.  -  508 

298,  507 

-  .  508 

-  -  508 

•  •  507 

-  .  508 

•  -  507 


....  297 

.  ...  608 

....  659 
.  -  659,660 

.  ...  660 

.  ...  660 
.660 

....  659 

.  ...  660 

.  ...  662 

.  ...  662 

.  ...  701 

...  701 

.  ...  662 

.  ...  717 

...  225 

...  713 

.  ...  690 

....  691 

...  691 

ative  .  691 

.  ...  684 

.  ...  684 


INDEX  OF  ACTIVE  SUBSTANCES 


Apocinchonine  chlor  derivative 685 

hydrobromide 684 

hydrochloride 684 

hydroiodide 684 

perchlorate 685 

sulphate 684 

Apoquinamine 694 

acetyl  derivative 694 

Apoquinidine 680 

chloride 680 

diacetyl  chloride 680 

diacetyl  derivative 680 

Apoquinine 677 

chloride 677 

Arabic  acid 611 

Arabin 611 

Arabinose,  d-  and  /- 574 

multirotation 259 

7-Arabinose 575 

Arabinosazone 575 

Arabitol 511 

structure 61 

Arabonic  acid 544 

anhydride 544 

multirotation 279- 

strontium  salt 544 

Arginine 668 

salts.  .   .       668 

Aribine 668 

Aricine 692 

Arsenyl  tartaric  acid 552 

tartrate,  dissociation 225 

Artificial  conine 709 

dextrine 609 

Asafetida  oil 662 

Asebotoxin 717 

Asparagin,  if- and  /-ft 541 

resolution 102 

Aspartic  acid 58,  540 

racemization 94 

rotation 211 

Aspidospermatine 669 

Aspidospermine 668 

Asymmetric  nitrogen  compounds  ....  52 

sulphur  compounds 53 

Atisine 668 

salts 668 

Atropine 669 

salts 669 

Aurantiin 714 

Aurantiol 612 

Australene 629 

Barium  ethyl  tartrate 556 

malate 533 

Basil  icum  oil 662 

Bcbirine 670 

Benzoyl  carvoxime 618 


Benzoyl  conine 709 

rf-ecgonine 699 

amylester  hydrochlor- 
ide     700 

butylester  hydrochlo- 
ride       700 

ethylester  hydrochlo- 
ride       699 

hydrochloride  ....  609 
methyl  ester  ....  699 
propyl    ester     hydro- 
chloride    699 

/-ecgonine,  methyl  ester 700 

h  y  d  ro- 

chloride  700 

-tartaric  acid  esters 559 

Benzyl  amyl  ether 509 

camphor  bromides 648 

valerate 514 

Berberine 670 

Bergamot  oil 661 

Betel  oil 662 

Biliary  substances 718 

Bioses 596 

Bitter  principles 715 

rf- Borneol 633 

acetate 633 

benzoate 634 

carbonate 634 

phenylurethanej 634 

phthalate 634 

succinate   .   .        634 

/-Borneol 634 

acetate 635 

benzoate 635 

carbonate 635 

phenylurethane 635 

phthalate 635 

succinate 635 

rf-Bornylamine 638 

derivatives 638 

chloride 633 

Boryl  tartrate,  dissociation 225 

rf-Bromal  borneol 633 

/-Bromal  borneol 635 

Brom-a-amyrin 660 

Brombenzoyl  carvoxime,  (>-,  m-  and  p-  .    .  618 

Bromcamphoric  acid 657 

Bromnitrocamphor 646 

Bromphenylcystein 526 

Bromphenylmeicapturic  acid 525 

Brompropionic  acid  esters 517 

Bromsuccinic  acid 540 

density   of  active   :in<l 

racemic  forms  .       ,  80 


esters  .   .   . 

inoiiainick- 


540 


INDEX  OF  ACTIVE  SUBSTANCES 


739 


Brucine  . 


used  in  resolution. 

Bulbocapnine 

Butylacetyl  malates 

nialates  

valeratej. 

Cadinene 

dihydrobromide.  .    .    . 

dihydrochloride.  .    .    . 

dihydroiodide  .... 

Cajaput  oil 

Calamus  oil 

Calcium  lactate 

Camphan  group 

</-Camphanic  acid 

ACamphanic  acid 

^-Camphene 


...  706 

...  706 

•  -    •  103 
...  707 

•  -    -  535 

•  •    •  5?5 

•  •    •  5'4 
...  658 

•  •    •  659 
...  658 
...  659 
...  662 
...  662 
.    -    .  516 
...  627 
...  649 
...  657 
...  627 


hydrochloride. 628 

/-Camphene 628 

a-  and  /3-Camphene  phosphoric  acid  .    .    .  629 

rf-Camphenol 6^7 

/-Camphenol ...  638 

Camphiiiic  acid .  649 

d-Camphocarboxylic  acid. 649 

derivatives  .  .   .  650 

/-Camphocarboxylic  acid  - 657 

Canipholic  acid 649 

Campholytic  acid 655 

Camphonitrophenol 646 

<f-Camphor 640 

and  terpenes 612 

detertnination 497 

dichloride 648 

leaf  oil 662 

oxime  and  derivatives.  ....  648 

resolution 114 

pinacone  and  derivatives  .    .    .  647 

rotation   in  different  solvents.  191 

sulphochloride 646 

sulphonamide 646 

/-Camphor 656 

oxime  and  derivatives  ....  656 

pinacone  

</-Camphoric  acids  .......          ...  651 

density 80 

esters 652,  653 

melting-point 83 

racemization 94 

salts 652 

solubilitv xi 

/-Camphoric  acid 

rf-Camphoroiiic  acid    .    .    . 
/-Camphoronic  acid.  . 

Cane  sugar -    59^  to  599 

constant  specific  rotation.  .    .  166 

determination 463 


Cane  sugar,  determination  in  presence  of 

raffinose    .  .    482 

Cane  sugar,  dispersion  coefficient  ....  155 
in  acetone  and  alcohol  ....  207 
influence  of  temperature  on 

rotation 598 

in  presence  of  invert  sugar.  .    476 
in  water,  dependence  on  con- 
centration .   .    195 
dilute  solutions.  .   .    196 
effect  of  temperature  598 
influence  of  alkalies 

and  salts 251 

rotation  dispersion  . 

155.  156 

Caproic  acid 514 

Caraway  oil 662 

Carbanilidocarvoxime 618 

Carbohydrates 607 

Carbo-0-w-,  and  /-.toluido  carvoximes  .   .    618 

Cardamom  oil 662 

Carone 658 

Carvene  • 614 

Carvol. 626 

rf-Carvone 626 

density 80 

hydrogen  sulphide  compound.  627 

oxime 627 

tetrabromide,  density 80 

/-Carvone 627 

hydrogen  sulphide  compound  .    627 

oxime 627 

</-Carvoxime 616 

/-Carvoxime 617 

Cascarilla  oil 662 

Casein 728 

Caulosterin 719 

Cedar  leaf  oil 662 

Cedar  wood  oil -662 

Celery  oil .    663 

Cellulose 610 

Cetylamyl  ether 509 

Chairamidine 698 

Chairamine 698 

Changes  in  rotation  of  tartaric  acid  ...    561 

Chelerythrine 671' 

Chitenine 678 

Chloral  alcoholate  camphor 648 

borneols 633,  635,  637 

camphor 648 

hydrate  camphor 648 

Chlorapocinchonine 685 

acetyl  derivative  .   .    685 
acid  hydrochloride  .    685 

chlorate 685 

neutral  hyd'chlor'de  685 

nitrate 685 

sulphate 685 


740 


INDEX  OF  ACTIVE  SUBSTANCES 


Chlorbromcamphor 645 

Chlorisocinchonine 683 

Chlornitrocamphor 646 

Chlorpropionic  acid 517 

rf-Chlorsuccinic  acid 539 

anhydride 539 

esters.  .   .  539 

chloride 540 

esters  of  chlo- 
ride ....  540 
density  of  active  es- 
ters and  racemic  form  Fo 

esters 291 

/-Chlorsuccinic  acid 540 

Cholalic  acid 720 

alcoholate '.   .   .  720 

esters 722 

potassium  salt 721 

sodium  salt 721 

Cholanic  acid 722 

barium  salt 722 

Cholecamphoric  acid 655 

Choleinic  acid 722 

Cholesterin 718 

esters 718 

Chondrin 724 

Cinchol 718 

Cincholeuponic  acid 691 

hydrochloride  .   .   .  692 

Cinchona  alkaloids 671 

determination     .   .   .  498 

Cinchonamine 698 

acid  sulphate 698 

neutral  sulphate 698 

Cinchonicine 687 

oxalate 688 

Cinchonidine 688 

acetyl  derivative 690 

acid  sulphate 689 

disulphate 689 

hydrochloride 688 

-f  2H2O  ...  689 

neutral  sulphate 689 

-r  3H20.  .  689 

nitrate 689 

oxalate 690 

sulphonic  acid 690 

used  in  resolution 103 

^Cinchonidine 690 

•y-Cinchonidine 690 

Cinchonifine 684 

Cinchonigine 683 

Cinchonine 680 

acetyl  derivative 682 

acid  hydrochloride 681 

chloride 682 

neutral  hydrochloride  ....  681 


Cinchonine  neutral  sulphate  .... 

oxalate 

used  in  resolution .... 

/3-Cinchonine 

g-Cinchonine 

Cinchotenicine 

Cinchotenidine 

Cinchotenine 

Cinnamic  acid  dichloride 

CinnamyW-ecgonine,  methyl  ester. 


681 
103. 
682 
682 
687 
687 
687 
524 
700 
hydro- 
chlo- 
ride   700 

Citrene 614 

Citronellal 613.  614 

rf-Cocaine 699 

/-Cocaine  (ordinary) 700 

constant  specific  rotation  ...    168 

determination 501 

Coca  leaves,  alkaloids  in 698 

Codeine 702 

derivatives 703 

hydrochloride 702 

sulphate 703 

Conchairamidine 698 

Conchairamine 698 

Concusconine 692 

a-methyl  sulphate  .  .       .    .    693 

/3-methyl  sulphate 693 

C-Coniceine 710 

5-Coniceine 710 

Conifer  oils 663 

Coniferin 713 

rf-Conine 708,  709 

acetate 709 

acetyl  derivative 709 

benzoyl  derivative 709 

hydrobromide 709 

hydrochloride 709 

resolution 112 

/-Conine 709 

Conquinamine 695 

acetate 696 

chlorate 696 

formate 696 

hydrobromide 696 

hydrochloride 696 

hydroiodide 696 

oxalate 697 

perchlorate 696 

Conquinine 678 

Convallamarin 714 

Convolvulin 714 

Convolvulinic  acid 667 

Copellidine,  resolution 112 

rf-Copellidine 712 

/-Copellidine 712 


INDEX  OF  ACTIVE  SUBSTANCES 


741 


Coriander  oil 663 

Coriandrol 612 

Corydaline 707 

Creeping  thyme  oil 663 

Cresol  aniyl  ether 510 

Cryptopine 705 

Crystallin 727 

Cupreine 671 

ethyl  ester 676 

formate 673 

isopropyl  ester,  sulphate  ....    676 

neutral  sulphate 673 

propyl  ester,  sulphate 676 

quinine 677 

quinine  sulphate 677 

salts 671,  672 

Cupreol 718 

Curled  mint  oil 663 

Cusconine 692 

Cyancamphor 646 

derivatives 647 

Cyclamose 604 

Cystin 525 

Cytisine 707 

nitrate 707 

Dehydromorphine 704 

Delphinine 707 

Delphinoidine 707 

Desoxycholic  acid 722 

Desoxystrychuine  hydrochloride   ....    706 

Deuteroalbumose 726 

Dextran 609 

Dextrines 608 

Dextropimaric  acid 666 

Dextrose 582 

determination 491 

rate  of  change  of  rotation  ...    267 

Dextrotartaric  acid,  salts 548 

Diacetylapoquinine 677 

Diacetyl  tartaric  acid 556 

anhydride 556 

compound  with  eth- 
ylene  diamine  .  557,  558 
dibutyl  ester  ...  557 
diethyl  ester  ....  557 
diisobutyl  ester  .  .  557 
dimethyl  ester  ...  557 
dipropyl  ester  ...  557 

Diamyl 505 

acetate 5^7 

amine 509 

amylmalonate 298 

antidimethylsuccinate 5°7 

bromfumarate 507 

brommaleate 5°7 

chlorfumarate 5°6>  5°8 

chlormaleate 5°6.  507 


Diamyl  chlorsuccinates 298,  507,  508 

citraconate 507 

divaleryl  tartrates 298 

fumarate 506,  508 

itaconate 507 

malates 298,  507,  534 

maleate 506,  507 

mesaconate 508 

mesotartrate 507 

methylsuccinate 508 

oxalate 506 

paradimethylsuccinate 507 

phthalate 506 

racemate 507 

succinate 508 

tartrate 298,  507 

Diapocinchonine 686 

diacetyl  derivative  ...    686 

Dibenzoylglyceric  acid  esters 250 

Dibtnzoylmethyl  tartrimide 561 

Dibenzoyltartaric  acid 558 

anhydride  ....  558 
diethyl  ester  .  558,  559 
diisobutyl  ester  .  .  559 
dimethyl  ester  558,  559 

Dibrommenthone 625 

Dicaniphor 655 

derivatives 656 

resorcin 649 

Dicaprylmalate 534 

Dichlorcamphor 643 

Dicinchonine 697 

hydrochloride 697 

Diethyl  acetylmalate 534 

amylmalonate 507 

amylnitrobenzylmalonate .  .   .   .    507 

bromacetylmalate 534 

brombut3-n-lmalate 534 

bromisobutyrylrnalate 534 

brompropionylmalate 534 

diamylmalonate 507 

dibenzoyltartrate 539 

di-o-, m-,p-,  toluyltartrates  ....    560 

isobutyrylmalate 534 

isovalerylmalate 534 

malate 534 

monobenzoyltartrate 559 

mono-r>-  »/-,/>-,toluyltartrates  .559,  560 

propionylmalate 534 

tartrate 555 

Digitalonic  acid 546 

Digitonin 7*4 

Dihydroxycyancampholytic  acid 655 

photosantinic  acid 716 

esters .   .   .  ^716 
Diisobutyl  acetylmalate 534 


742 


INDEX  OF  ACTIVE  SUBSTANCES 


Diisobutyl  broinacetylmalate 534 

»-butyrylmalate 534 

cinchonine  hydrobromide   .   .    682 

isovalerylmalate 534 

malate 534 

tartrate 556 

Diisopropyl  malate 534 

tartrate 556 

Dill  oil 664 

Dimethyl  acetylmalate 534 

bromacetylmalate 534 

«-butyrylmalate  .  ....    534 

chloracetylmalate 534 

dibenzoyltartrate 559 

di-o-.Jw-^-.toluyltartrates.  .    .   .    560 

isobutyrylmalate 534 

malate 534 

nitromalate 534 

propionylmalate 534 

tartrate 555 

Diphellandrene 619 

Diphenyl  acetyltartaric  acid  anhydride  .    559 
ethylene  diamine   ....  510 

propionyltartaricacidanhy'ri'e  559 

Dipropyl  acetylmalate 534 

bromacetylmalate 534 

w-butyryl  malate 534 

chloracetylmalate 534 

isovalerylmalate 554 

malate 534 

tartrate 556 

Diquinine  sulphate 675 

Disaccharides 596 

Diterpenes 659 

Diterpilene • 659 

Dog  fennel  oil 664 

Dulcitol 512 

Dwarf  pine  oil 663 

rf-Ecgonine 698 

derivatives 699 

hydrochloride 699 

methyl  ester 699 

/-Ecgonine  hydrochloride 700 

Ecgoninic  acid 701 

Echicerin 717 

Echiretin     717 

Echitein 717 

Echitatnine 707 

Kchitin 717 

Egg  albumin 725 

Elastin  peptone 728 

Elemi  oil 664 

Ergosterin 719 

Esters  of  rf-amylacetic  acid 515 

brompropionic  acid 517 

chlorpropionic  acid 517 

glycericacid 523 


Esters  of  lactic  acid 516,  517 

/-mandelic  acid 520 

methoxysuccinic  acid 537 

oxybutyric  acid 518 

phenyl  bromacetic  acid    ....  522 

chloracetic  acid    ....  521 

dichlorpropionic  acid    .  524 

tartaric  acid 554 

valeric  acid 514 

Ethereal  oils     660 

Ethoxysuccinic  acid,  resolution 106 

rf-Ethoxysuccinic  acid 538 

acid  am'onium  s'lt  538 

barium  salt    .   .    .  538- 

calcium  salt    .   .   .  538 

esters  of 538 

normal     ammoni- 
um salt 538 

/-Ethoxysuccinic  acid 539 

acid  ammonium  salt  539 

esters 539 

Ethyl  acetylmalate 535 

amyl     505 

amylacetate 507 

amylacetoacetate 507 

amylether 509 

benzoylmalate 535 

borneol 633 

camphene 628 

dextrotartrate 185,  555 

diamylacetate 507 

diamylacetoacetate 507 

malate 535 

o-,  «/-,/>-, toluylmalates 535 

piperidine,  resolution 112 

tartaric  acid 555 

barium  salt 555 

calcium  salt 555 

lithium  salt 555 

potassium  salt   ....  555 

sodium  salt 555 

tartrimide 561 

valerate 514 

Ethylene  diamine  ditartrate     554 

Eucalyptus  oil 664 

Euphorbon     717 

/-Fenchene 633 

Fenchol 637 

rf-Fenchone 657 

oxime 657 

density 80 

/-Fenchone 658 

oxime 658 

rf-Fenchyl  alcohol 637 

/-Fenchyl  alcohol 637 

rf-Fenchyl  amine 639 

l>en/.ylidene  compound  659 


INDEX  OF  ACTIVE  SUBSTANCES 


743 


.-Fenchyl  amine 639 

acetyl  compound  ....  639 

benzylidene  compound  639 

Imtyryl  compound  .   .   .  639 
derivatives,    change    in 

rotation 292 

formyl  compound    .   .   .  639 
methoxybe  nzylidene 

compound 640 

oxybenzylidene    c  o  in  - 

pound 640 

propionyl  compound     .  639 

Fennel  oil 664 

Fermentation  gum     609 

lactic  acid,  resolution  ...  101 

Fibrinogin 726 

Fir  needle  oil 663 

Frankincense  oil      664 

<f-Fructose 589 

multirotation 265 

Fruit  sugar 589 

Fucose 577 

multirotation 264 

£-Galactan 607,  609 

•y-Galactan 609 

a-Galactin 609 

Galactonic  acid,  resolution 107 

rf-Galactomc  acid 566 

calcium  sail 567 

multirotation 279 

d-  Galactose 579 

anilide 581 

carboxylic  acid 569 

determitiation 496 

multirotation      262,  580 

oxime 581 

multirotation     ....  262 

pentacetate 581 

phenylhydrazone 581 

structure 62 

/-toluide 581 

/-Galactose 581 

Galaheptilol 513 

/3-Galaheptose 588 

Galaoctonic  acid 572 

Galaoctose 589 

Galbanum  oil 664 

Gallisin 604 

Geissospermine       697 

Gelatinous  substances 723 

Gentianose 607 

Geraniol 613 

Geranium  oil     664 

Ginger  oil 664 

Globulin 727 

a-Glucoheptonic  acid ^69 

structure 64 


/3-Glucoheptonic  acid     569 

multirotation    .    .    .  280 

structure 64 

'  a-Glucoheptose 588 

multirotation 265 

structure 64 

0-Glucoheptose     588 

structure 64 

rf-Gluconic  acid 565 

anhydride 565 

calcium  salt 565 

multirotation 279 

structure 62 

/-Gluconic  acid 566 

anhydride 566 

calcium  salt 566 

a-Gluconononic  acid 573 

a-Glucooctitol 513 

a-Glucooctonic  acid 572 

/3-Glucooctonic  acid 572 

a-Glucooctose 588 

multirotation 265 

/3-Glucopentoxypimelic  acid,  structure    .  65 

Glucoronic  acid 568 

anhydride 568 

potassium  salt 568 

Glucosaccharinic  acid  anhydride    ....  545 

rf-Glucose 582 

amine  hydrobromide 585 

hydrochloride 584 

anilide 586 

derivatives 584 

determination 491 

ethyl  mercaptal 586 

in  presence  of  inactive  bodies  .  584 

monochlorhydrin  tetracetate    .  585 

multirotation 260 

oxime 585 

multirotation  ......  261 

paratoluide 586 

phenylhydrazone 586 

multirotation  261 

structure 62 

tetrasulphuric  acid  chloride  .   .  585 

trisulphuric  acid 585 

/-Glucose 586 

multirotation 262 

Glucosides 713 

synthetic 714 

Glucovanillin 713 

rf-Glutamine 543 

Glutaminic  acid,  density  of  active  and  ra- 

cemic  forms 80 

rf-Glutaminic  acid 542 

calcium  salt 542 

hydrochloride    ....  542 

/-Glutaminic  acid 543 


744 


INDEX  OF  ACTIVE  SUBSTANCES 


r-Glutaminic  acid,  resolution 102 

a-Glutin 723 

0-Glutin 723 

d-Glyceric  acid 523 

esters,  rotation 290 

salts,  solubility 81 

Glycocholic  acid 719 

sodium  salt 719 

Glycogen 609 

Gossypose 605 

Graminin 610 

Grape  sugar 582 

determination 491 

Gulonic  acid  lactone,  resolution 101 

rf-Gulonic  acid 566 

anhydride 566 

structure 62 

Gulose,  structure 62 

Gurjon  balsam  oil 664 

Helicin 713 

Hemicamphor  phenol 649 

Hemielastin 728 

Hemlock  oil 663 

Hemp  oil 6^9 

Heptitols 512 

Hesperidene 614 

Hesperidin •. 714 

Heteroalbumose 726 

Hexitols 511 

rf-Hexylalcohol 510 

rf-Hexylcaproate 514 

Homoaspartic  acid,  resolution 102 

cinchonidine 691 

acetyl  derivative    .   .  691 

hydrochloride     .   .   .  691 

sulphate 691 

cinchonine 686 

dihydrochloride   ...  686 

hydrochloride  ....  686 

Homoconic  acid 710 

Homoquinine 677 

Hop  oil 664 

Hydrastine 671 

salts 671 

Hydrastinine 671 

Hydrocarbons 505 

Hydrochlorcinchonine  dihydrochloride  .  682 

Hydrocinchonidine 694 

acetyl  derivative     .   .  695 

acid  sulphate    ....  695 

hydrochloride  ....  695 

neutral  sulphate     .   .  695 

Hydronicotine 712 

Hydroquinicine 697 

Hydroquinine 697 

acetyl  derivative 697 

neutral  sulphate 697 


Hydroshikimic  acid 544 

dibromide 544 

Hyoscine 670 

Hyoscyamine 669 

salts 670 

Hyposantonic  acid 716 

Iditol,  structure 63 

rf-Idonic  acid 567 

/-Idonic  acid 567 

structure 62 

Idose,  structure 62 

Imides  of  tartaric  acid 561 

Imperialine 707 

Indifferent  bodies 715 

Inositol 50,  81,  512 

Inulein 610 

Inulin 610 

Inversion  of  sugar 593 

Invert  sugar 591 

and  inactive  bodies    ....  594 

composition 595 

effect  of  temperature  on  ro- 
tation    213 

influences  affecting  rotation  592 

Irisin 61 1 

rf-Iroue 627 

Isaconitine 667 

hydrobrottiide 667 

hydrochloride 667 

hydroiodide 667 

Isatropylcocaine 701 

Isoamylamyl  ether 509 

Isoapocinchonine 686 

chlor  derivative  ....  686 

dihydrochloride     ...  686 

Isoborneol 637 

Isobutylamyl 505 

camphene 628 

ether 509 

a-Isobutyl  piperidine 710 

Isobutyl  valerate     514 

Isocamphenol 638 

Isocampholic  acid,  ethyl  ether 649 

Isocamphoric  acid 654 

density 80 

esters 655 

Isocholesterin 719 

a-Isocinchonine 682 

hydrochloride 683 

/3-Isocinchonine 683 

hydrochloride 683 

Isoconine 709 

benzoyl  derivative 710 

Isocopellidine,  resolution       112 

rf-Isocopellidine 712 

/-Isocopellidine 712 

Isodulcite 577 


INDEX  OF  ACTIVE  SUBSTANCES 


745 


Isodulcite,  multirotation 263 

Isodulcitan 578 

Isodulcitonic  acid 546 

Isohesperidin 714 

Isomaltose 604 

Isopilocarpine 708 

h3rdrobromide 708 

hydrochloride 708 

nitrate 708 

rf-Isopropylphenylchloracetic  acid     ...  522 

Isopropylphenylglycolic  acid,  resolution  no 

tf-Isopropylphenylglycolic  acid 522 

racerniza- 

tion    .   .  94 

/-Isopropylphenylglycolic  acid 522 

Isopulegol 622 

Isorhamnonic  acid,  lactone 546 

Isosaccharic  acid 571 

dianiide 571 

diethyl  ether 571 

Isosaccharin 545 

Msoterebentheiie 632 

rf-Isoterpene 632 

/-Isoterpene 632 

Isotrioxystearic  acid 544 

Ivy  leaf  glucoside 714 

Juniper  oil 664 

Ketoses 589 

Koprosterin 719 

a-Lactacerol 718 

£-Lactacerol 718 

Lactalbumin      725 

(/-Lactic  acid 515 

/-Lactic  acid 516 

esters 284,  516,  517 

multirotation 280 

resolution 107 

Lactobiose 599 

Lactoglucose 579 

Lactose 599,  601 

determination 488 

multirotation 265 

Lactosin 612 

Laudanidine 704 

Laudanine 704 

hydrochloride 704 

Laudanosine 704 

Laurel  camphor 640 

determination 497 

rotation  of  solid  ....  15 

I^avender  oil 664 

Lavendol 612 

Lemon  oil 661 

dispersion  coefficient 155 

Leucin,  solubility 81 

rf-Leucin 518 

/-Leucin 519 


Levosin     

Levulan 

Levulose  

carboxylic  acid 
multirotation  . 

Licarene 

Licareol,  d-  and  /-    .   .    .   , 


.  611 

.  611 

•  589 

•  569 
.  6*6 
.  612 
.  612 


Licarhodol 613 

acetate 613 

Lime  oil 664 

Limonene 49 

rf-Limonene 614 

benzoylnitrosochloride   .   .  .  615 

hydrochloride 614 

hydrochlor-nitrolbenzylam- 

ine 615 

a-  and  /3-nitrolanilides  .  .  .  615 
a-nitrolbenzylamine  ....  615 
a-  and  /3-nitrol  piperidine  .  616 
a-  and  /3-nitrosochlorides  614,  615 

/-Limonene 616 

benzoyl  compound 618 

nitrosochloride  .   .   .    617 

hydrochloride 616 

a-  and  jS-nitrolanilides  ....    617 

nitroso  compounds  ......    617 

a-  and  /3-nitrol  piperidines  .   .    617 

a-nitrosochloride 616 

/3-nitrosochloride 617 

tetrabromide 616 

/-Linalool 612,  613 

Lithium  lactate 516,  517 

malate 531 

Lithofellinic  acid 723 

L«peol 717 

Lupeose 607 

Lycaconitine 668 

Lyxonic  acid 545 

structure 60 

!   Lyxose,  structure 60 

!   Mace  oil 665 

/-Malamide 564 

Malic  acids 212,  526,  535 

action  of  molybdates  and 

tungstates 250 

density  of  different  forms  .   .      80 

diamide 534 

dianilide 534 

di-o-  and  -/-toluides 534 

direction  of  rotation,  reversal 

of 201 

esters,  constitution  and  rota- 
tion     282 

rotation 291 

in  different  solvents 528 

melting-point 83 

naphtimide 534 


746 


INDEX  OF  ACTIVE  SUBSTANCES 


Malic  acid,  resolution  of 106 

rotation  dispersion 159 

Maltodextrine 608 

Maltose 601,  603 

determination 495 

multirotation 266 

Maltosaccharinic  acid  anhydride   ....  545 

Mandarin  oil 665 

Mandelic  acid,  density 80 

resolution 108 

rf-Mandelic  acid 520 

racemization 94 

/-Mandelic  acid 520 

esters 520 

rf-Mannitol 5" 

/-Mannitol 512 

Mannitol  group,  action  of  molybdates  .  .  256 

action  with  borax    .   .   .  253 

me'ting-point 83 

structure 63 

Mannoheptitol 5" 

melting-point 83 

rf-Mannoheptonic  acid •  .  569 

anhydride    ....  570 

/-Mannoheptonic  acid 570 

rf-Mannoheptose 265,  588 

/-Mannoheptose 588 

Mannonic  acid  anhydride 566 

resolution 107 

rotation 566 

structure 62 

rf-Mannonononic  acid 574 

Mannononose 589 

Mannooctonic  acid 572 

rf-Mannooctose     588 

Mannosaccharic  acid 571 

structure 63 

rf-Mannose 587 

oxime 587 

multirotation 263 

structure 62 

/-Man  nose 587 

Mastic  oil 665 

Matezitol 512 

Matico  camphor 658 

rotation  of  solid   ....  14 

Matricaria  camphor 656 

Melezitose 606 

acetate 606 

Melibiose 604 

Melitose 605 

Melitriosc 605 

Melting-point  of  active  and  racemic  forms  83 

</-Menthene 619 

/-Menthene 620 

structure 49 

/-Menthol  .  .  .620 


/-Menthol,  ben  zoic  acid  ester 621 

carbonate 620 

phenylcarbamic  acid  ester    .   .  621 

phthalic  acid  esters 621 

succinic  acid  esters 620 

tolylcarbamic  acid  esters  .    .    .  621 

urethane 620 

rf-Menthone 625 

dibrom  compound 625 

oxime 625 

hydrochloride    ....  625 

/-Menthone 625 

oxime 626 

hydrochloride    ....  626 

rf-Menthylamine 622 

acetyl  compound    .   .   .  623 

butyryl  compound  .  .    .  624 

formyl  compound  .    .   .  623 

hydrobromide 623 

hydrochloride 623 

hydroiodide 623 

propionyl  compound    .  623 

/-Menthyl  amine 624 

acetyl  compound ....  624 

butyryl  compound  .   .    .  625 

formyl  compound  .   .    .  624 

hydrobromide 624 

hydrochloride 624 

hydroiodide 624 

propionyl  compound   .  624 

Menthyl  esters,  table  of 621 

Mesotartaric  acid 60 

Metasaccharin 546 

Metasaccharinic  acid  anhydride 546 

Metasantonin 715 

Methocodeine 703 

derivatives 703 

Methoxysuccinates,  solubility 81 

Methoxysuccinic  acid,  resolution  of  ...  106 

rf-Methoxysuccinic  acid 536 

esters 537 

salts 536,537 

/-Methoxysuccinic  acid 537 

esters 537 

salts 537 

Methyl  acetylmalonate 535 

amylether 509 

benzoylmalate 535 

camphor 642 

codeine,  sulphate 703 

conine 709 

ester  of  methoxysuccinic  acid  .   .  537 

hexose 587 

hexyl  carbinol 510 

hexyl  ketone 510 

malate 535 

piperidine 708 


INDEX  OF  ACTIVE  SUBSTANCES 


747 


Methyl  propyl  phenyl  amyl  ethers.    .    .    ;io 

tartaric  acid 554 

salts 555 

tartrimide 561 

i>-,  ///-,  and  />-toluylmalate   ....    535 

valerate 514 

Milk  sugar 599,  601 

birotation 600 

constant  specific  rotation  .  .    .    167 

determination 488 

multirotation 265 

octoacetate 601 

a-Monobronicamphor 643 

sulphochloride  .   .    644 

sulphonamide    .   .    644 

sulphonic  acid  .   .    644 

salts  644 

/3-Monobrom  camphor 645 

•y-Monobrom  camphor 645 

Monocamphor  phenol 649 

Monocamphor  resorcin 649 

o-Monochlorcamphor 642 

sulphochloride  .  .  643 
sulphonamide .  .  .  643 
sulphonates  ....  643 

/3-Monochlorcaraphor 643 

y-Monochlorcamphor 643 

Monoiodo  camphor 645 

Monomethyl  tartrate 554 

Morphine 701 

acetate 702 

hydrochloride 702 

sulphate 702 

used  in  resolution 104 

Mucic  acid  .   .    . 571 

My  cose 604 

Napeliine 667 

a-  and  /3-Naphthol  camphor 649 

Narceine 705 

Narcotine 705 

Naringin 7J4 

Natural  conine 708 

malic  acid 526 

Nicotine 710 

acetate 711 

anomalous  dispersion 161 

constant  specific  rotation  ....    168 

determination 503 

hydrochloride 711 

minimum  specific  rotation  ...    197 

neutral  sulphate 711 

rotation  in  different  solvents  .  .    181 

salts 7" 

Nitrobenzoylcarvoximes 618 

Nitrocamphor 645 

derivatives 645,  646 

quinine 677 


Nitromannitol 511 

Xitrosocamphor 646 

Norisosaccharic  acid 571 

Octacetyl  diglucose 585 

maltose 603 

melibiose 604 

Oils,  ethereal 660 

Onion  oil 665 

Opianine 705 

Opium  alkaloids 701 

Orange  flower  oil 665 

oil 661 

Ordinary  milk  sugar 599 

Oubain 714 

Oxyacanthine 670 

hydrochloride 670 

Oxyacids,  multirotation 275 

Oxyaldehydes 574 

Oxy-a-aniyrin 659 

a-Oxybutyric  acid,  resolution  of 107 

/3-Oxybutyric  acid 518 

Oxycamphocarboxylic  acid 650 

esters  ....  650 

a-Oxycinchonine 687 

hydrochloride 687 

/3-Oxycinchonine 687 

Oxydimorphine 704 

Oxyethylbrucine  hydrochloride 706 

Oxygluconic  acid 568 

Oxyketones 589 

Oxypropionic  acids 518 

Palma  rosa  oil 665 

Papaverine 705 

Paracholesterin 719 

i  Paraconine 710 

Paracotol 659 

Paralactic  acid 515 

Paraphytosterin 719 

Parasaccharinic  acid 546 

Parasantonic  acid 715 

esters 715 

Parasantonide,  constant  specific  rotation  167 

Parasorbic  acid 515 

Paricine 697 

Patchoulene 659 

Patchouli  camphor 658 

rotation  of  solid  ...  15 

Paytine 669 

Pea  albumin 725 

Pennyroyal  oil 665 

Pentitols 511 

Pentoxypimelic  acids,  a-  and  ft- 572 

Peppermint  oil 665 

Phasol 718 

Phellandrene 619 

nitrate 619 

Phenacetylcarvoxime 618 


748 


INDEX  OF  ACTIVE  SUBSTANCES 


Phenolamylether 510 

Phenoxacrylic  acid 49 

Phenyl  bromacetic  acid 522 

a-bromlactic  acid,  resolution    .   .  no 

chloracetic  acid 521 

dibrombutyric  acid,  resolution    .  109 
a-  and  0-dibrompropionic    acid, 

resolution 108 

dichlorpropionic  acid .524 

a-  and  ^-dichlorpropionic    acid. 

resolution 109 

ethylamine,  resolution 113 

mercapturic  acid 525 

Phlein 611 

Phloridzin 713 

Photosantoniu 716 

Phytosterin 719 

Picien 714 

Picrotoxin 717 

Pilocarpidine 708 

nitrate 708 

Pilocarpine 707 

hydrobromide  .       708 

hydrochloride 708 

nitrate 708 

sulphate 708 

Pine  needle  oil 663 

rf-Pinene 629 

dibromide 630 

hydrochloride 630 

/-Pinene 631 

hydrobromide 632 

hydrochloride 632 

Pinitol 512 

Pinol  hydrates,  d-  and  /- 638 

Pipecoline 708 

resolution  of  a-  and  ft-  forms  . 

in,  112 

Pipecolinic  acids,  d-  and  /- 515 

Pipeline 708 

Podocarpinic  acid 666 

Polei  oil 626 

Polyterpenes 658 

Populin 713 

Potassium  antimonyl  tartrate 553 

arsenyl  tartrate 553 

ethyl  tartrate 556 

hydromalate 531 

malate 531 

tartrates 548 

Propeptones 726 

Propionylquinine 677 

d-Propoxysuccinic  acid 539 

salts 539 

/-Propoxysucctnic  acid 539 

salts  and  esters  .   .  539 

Propyl  acetylmalate 535 


Propyl  amyl 505 

ether 509 

malate 535 

a-piperidine 708 

resolution 112 

/3-piperidine 710 

tartrates  in  different  solvents   .   .  206 

valerate 514 

Propylene  diamine,  resolution 112 

glycol 58 

oxide 49 

Protein  bodies 724 

Pseudo  cinchonine 686 

dihydrochloride   .   .    .  687 

codeine 703 

hyoscyamine 670 

inulein 610 

morphine 704 

hydrochloride 704 

narceine 705 

Pulegone ;  626 

bromide 626 

oxime 626 

oxime 626 

hydrochloride 626 

Ptyalose 601 

Pyroaconine  hydrochloride 667 

Pyroaconitine 667 

hydrobromide 667 

Pyroglutaminic  acid,  d-  and  /- 543 

Pyrotartaric  acid,  resolution 106 

Quebrachine 669 

Quebrachitol 512 

Quebrachol 718 

Quinamicine • 694 

Quinamidine 694 

hydrochloride 694 

Quinamine 693 

hydrobromide 693 

hydrochloride 693 

hydroiodide 693 

nitrate 694 

perchlorate 694 

Quinic  acid 565 

salts 565 

Quinicine 678 

oxalate 678 

Quinidine 678 

acetyl  derivative 680 

acid  hydrochloride 679 

acid  sulphate 679 

neutral  hydrochloride    ....  678 

neutral  sulphate 679 

nitrate 679 

oxalate 680 

used  in  resolution 103 

Quinine 673 


INDEX  OF  ACTIVE  SUBSTANCES 


749 


Quinine,  acetyl  derivative 677 

anhydride 673 

determination 498 

disulphate 675 

hydrochloride 674 

nitrocamphor  derivative  ....  677 

oxalate 676 

propionyl  derivative 677 

sulphate 675 

sulphonic  acid 676 

used  in  resolution 103 

Racemic  acid,  resolution 104 

Raffhiobiose 604 

Raffinose 605 

Resin  acids 666 

Rhamiiitol 511 

Rhamnodulcite 577 

Rhamnoheptonic  acid 570 

Rhamnoheptose 588 

Rhamnorexitol 512 

Rhamnohexonic  acid  .  .    . 567 

anhydride 567 

Rhamnohexose 587 

multirotation 265 

Rhamnooctonic  acid 572 

Rhamnonic  acid 546 

multirotation 278 

Rhamnose 577 

constant  specific  rotation  .  .   .  167 

multirotation 263 

oxime 579 

multirotation 264 

phenyl  hydrazone 579 

Rhodinol,  d-  and  /- 613 

acetate 613 

Ribonic  acid 545 

anhydride 545 

cadmium  salt 545 

structure 60 

Ribose,  structure 60 

Ricinelaidic  acid 519 

Ricinoleic  acid 519 

Ricinstearoleic  acid 519 

Rochelle  salt 550 

Rosemary  oil 665 

Rubidium  tartrate,  rotation  of  solid  ...  16 

Russian  oil  of  turpentine 629 

Saccharic  acid 570 

ammonium  salt 570 

multirotation 278 

structure 63 

Saccharimetry 463 

Saccharin «45 

multirotation 280 

Saccharinic  acid,  multirotation 280 

Saccharonic  acid  and  anhydride 568 

Saccharose 596,  597,  598 


Saccharose,  determination 463 

Saccharoses 596  to  604 

Salicin 713 

Salicylic  acid  camphor 649 

Salts  of  /-glyceric  acid 523 


d-  and  /-isopropylphenyl  glycolic 

acid .    .  522 

lactic  acid 516 

malic  acid 531 

d-  and  /-mandelic  acid 520 

£-oxybutyric  acid 518 

oxypropionic  acid 518 

rf-tartaric  acid 548 

/-tartaric  acid 563 

Sandalwood  oil 665 

Santinic  acid 716 

Santonic  acid 715 

esters 715 

Santonide 715 

constant  specific  rotation  .   .    .  168 
Santonin    bodies,    specific    rotation    for 

different  colors 716 

dispersion  coefficient 155 

group 715 

Santonious  acid 717 

Santonyl  bromide 715 

chloride 715 

iodide 715 

Sarcolactic  acid 515 

Sassafras  oil 665 

Savin  oil       665 

Scopolamine 669 

Semmose 587 

Serum  albumin 724 

globulin 727 

Sesquiterpenes 658 

Shikimic  acid 543 

ammonium  salt 543 

bromide 544 

derivatives 543 

Silver  fir  oil 663 

Sinistrin 611 

Sobrerol,  density  of  active  and  racemic 

forms 80 

Sodium  ammonium  tartrates  ....  552,  563 

arsenyl  tartrate 553 

malate  and  hydromalate  ....  531 

tartrates 548 

Soluble  starch 607 

Sorbin 582 

Sorbinose 582 

Sorbitol 512 

structure 63 

Sorbose 582 

Sparteine 708 

Spike  oil 666 

Staphisagrine 707 


750 


INDEX  OF  ACTIVE  SUBSTANCES 


Star  anise  oil 666 

Starch,  soluble 607 

sugar 582 

Storax  oil 666 

Strychnine 706 

salts 706 

sulphate,  rotation  of  solid  .   .  17 

used  in  resolution 103 

Strychnos  alkaloids 706 

Sugar 596 

cause  of  multirotation 273 

changes  in  rotation 194 

directions  for  tests 467 

formulas  for  specific  rotation  .   .   .  195 

in  confectionery 487 

rotation  in  presence  of  alkalies  .   .  251 

temperature  effect  ....  598 

Sweet  marjoram  oil 666 

rf-Sylvestrene 618 

dihydrobromide ......  618 

dihydrochloride 619 

nitrolbenzylamine 619 

tetrabromide 619 

/-Sylvestrene 619 

Synthetic  conine,  resolution  . 112 

glucosides  ...."?. 714 

Syntonin 727 

Talitol 512 

structure 63 

Talomucic  acid 62,  571 

Talon  ic  acid 567 

structure 62 

Talose,  structure 62 

Tanacetone 626 

Tannic  acid ...  37.; 

Tannin 573 

Tansy  oil 666 

Tarragon  oil 666 

Tartar  emetic 553,  563 

action  of  alkali  salts  ....  245 

d- Tartaric  acid 546,  547 

action  of  molybdates  and 

tungstates 248 

density  of  active  and  ra- 

ctrmic  forms 80 

effect  of  boric  acid  on  ro- 
tation    246 

esters 554  to  563 

melting-point 83 

rotation  dispersion  ....  157 

solubility 81 

specific  rotation  of  dilute 

solutions 196 

structure 60 

/-Tartaric  acid 562 

ammonium  salt 563 

calcium  salt 564 


/-Tartaric  acid,  potassium  antimonyl  salt  563 

sodium  salt 563 

Tartrates,  acid  ammonium 548 

boryl 552 

lithium 548 

potassium 548 

sod  iu  in 548 

thallium 549 

ammonium 551 

— potassium  .  .    .    .  551 

—sodium 552 

lithium 551 

magnesium 552 

potassium 549 

—antimonyl  ....  553 

—boryl 552 

sodium 550 

— potassium 550 

—boryl 552 

thallium 553 

— ammonium   ...  554 

—antimonyl 554 

—lithium 554 

— potassium 553 

—sodium 554 

and  malates.  combinations  .    .  564 

dissociation 225 

formation  of  racemic  bodies   .  91 
influence  of  alkali  sails  on  ro- 
tation    243 

transition  temperatures  ....  91 
water  of  crystallixation  of  dif- 
ferent forms 79 

'  Tartrimides 561,  564 

Tartromalamides 564 

Taurocholic  acid 719 

sodium  salt      719 

-  Temperature,    influence    cm   rotation  of 

sugar 598 

Terebenthene    629 

Terecamphene 628 

acetate 629 

formate 629 

hydrochloride 628 

Terpan  group 614 

r/-Terpineol 622 

ATerpineol 622 

formate 622 

Tetrahydronaphthylene  diamine   ....  511 

resolution  113 

Tetrahydropapaverine,  resolution  ....  114 

Tetrahydroquinaldine 712 

resolution  .   .    .  1 13,  114 

Tht-baine 704 

hydrochloride 704 

Thuja  oil 666 

Thujone    ...           626 


INDEX  OF  ACTIVE  SUBSTANCES 


751 


Toluy  Icarvoximes,  o-,  «/-,  and  p- 
Toluyltartaric  acid  esters 

Trehalose 

Trehalum 

Triacetylshikimic  acid  .    . 

Triamylaconitate 

Triamyltricarballylate  .   . 

Trichlorcamphor 

Triisobutyrylshikimic  acid 
Trioxyglutaric 

potassium  salt 

structure 
Tripropionylshikimic  ac 

Triterpene 

Triticin 

Tropic  acid,  d-  and  /- .  . 
resolution  . 

Tropinic  acid 

Turpentine 

oil 

dispersio 

rotation  i: 

rotation  c 
Turpethinic  acid  .... 

Tyrosin 

Valeraldehyde 509,  513 


559 

d-  Valeric  acid 

•y,  D  4 

604 

/-Valeric  acid  

.--.    5M 

607 

Valeric  acid  esters  

...    514 

543 

rotation  .  .   . 

290 

508 

resolution  of    ... 

....    107 

508 

Valerion  oil  

....    666 

643 

Venetian  turpentine  

....    631 

544 

Viscose  

....    609 

567 

Vitellin  

727 

t   567 

Volemitol  

•       •   •    513 

61 
544 

Wheat  albumin    
AiVoocl  cru  ni 

....     725 
611 

659 

Xylan  

611 

611 

Xylitol  

5" 

522 

structure  

61 

108 

Xvlonic  acid 

_^ 

701 

multirotation  .   .   . 

280 

629,  631 

strontium  salt 

545 

663 

Xylosazone  

576 

efficient.  .   .    155 

Xylose   

575 

"erent  liquids  177 

multirotation  

260 

ixed  oils    .   .    240 

structure 

60 

667 

Ylang-ylang  oil 

666 

-    525 

Zinc  lactate  .   . 

.    .  Sl6.    SI7 

ERRATA. 

On  page  60,  half  the  structural  formula  for  xylose  and  xylonic  acid  is  missing. 
On  page  684,  read  cinchonifine  for  cinchonidine. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
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REC'D  LD 

DEC  2  7  1956 


TER-LIBRARY 
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MAY  2  5  1964 


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